Contents

List of Examples

List of Figures

List of Tables

Title and Copyright Information

Preface

Audience

Documentation Accessibility

Related Documents

Conventions

1 Using Java with Oracle Database

1.1 Using Java to Connect to Oracle Database

1.1.1 Oracle JDBC Thin Driver

1.1.2 Oracle JDBC OCI Driver

1.1.3 Oracle JDBC Packages

1.2 Using JDeveloper to Create JDBC Applications

1.2.1 JDeveloper User Interface

1.2.2 JDeveloper Tools

1.3 Overview of Sample Java Application

1.4 Advanced Application Development Using Developer Frameworks

2 Getting Started with the Application

2.1 What You Need to Install

2.1.1 Oracle Database Server

2.1.1.1 Modifying the HR Schema for the JDBC Application

2.1.2 Oracle Database Client

2.1.3 J2SE or JDK

2.1.4 Integrated Development Environment

2.1.5 Web Server

2.2 Verifying the Oracle Database Client Installation

2.2.1 Checking Installed Directories and Files

2.2.2 Checking the Environment Variables

2.2.3 Determining the JDBC Driver Version

2.3 Installing Oracle JDeveloper

2.3.1 JDeveloper Studio Edition: Base Installation and Full Installation

2.3.2 Steps to Install JDeveloper

2.3.3 Starting JDeveloper

3 Connecting to Oracle Database

3.1 Connecting to Oracle Database from JDeveloper

3.1.1 JDeveloper Database Navigator

3.1.2 Creating a Database Connection

3.1.3 Browsing the Data Using the Database Navigator

3.2 Setting Up Applications and Projects in JDeveloper

3.2.1 Using the JDeveloper Application Navigator

3.2.2 Creating an Application and a Project

3.2.3 Viewing the Javadoc and Source Code Available in the Project Scope

3.3 Connecting to Oracle Database from a Java Application

3.3.1 Overview of Connecting to Oracle Database

3.3.2 Specifying Database URLs

3.3.2.1 Using the Default Service Feature of the Oracle Database Client

3.3.3 Creating a Java Class in JDeveloper

3.3.4 Java Libraries

3.3.4.1 Overview of the Oracle JDBC Library

3.3.4.2 Overview of the JSP Runtime Library

3.3.5 Adding JDBC and JSP Libraries

3.3.6 Importing JDBC Packages

3.3.7 Declaring Connection-Related Variables

3.3.8 Creating the Connection Method

4 Querying for and Displaying Data

4.1 Overview of Querying for Data in Oracle Database

4.1.1 SQL Statements

4.1.2 Query Methods for the Statement Object

4.1.3 Result Sets

4.1.3.1 Features of ResultSet Objects

4.1.3.2 Summary of Result Set Object Types

4.2 Querying Data from a Java Application

4.2.1 Creating a Method in JDeveloper to Query Data

4.2.2 Testing the Connection and the Query Methods

4.3 Creating JSP Pages

4.3.1 Overview of Page Presentation

4.3.1.1 JSP Tags

4.3.1.2 Scriptlets

4.3.1.3 HTML Tags

4.3.1.4 HTML Forms

4.3.2 Creating a Simple JSP Page

4.3.3 Adding Static Content to a JSP Page

4.3.4 Adding a Style Sheet to a JSP Page

4.4 Adding Dynamic Content to the JSP Page: Database Query Results

4.4.1 Adding a JSP useBean Tag to Initialize the DataHandler Class

4.4.2 Creating a Result Set

4.4.3 Adding a Table to the JSP Page to Display the Result Set

4.5 Filtering a Query Result Set

4.5.1 Creating a Java Method for Filtering Results

4.5.2 Testing the Query Filter Method

4.5.3 Adding Filter Controls to the JSP Page

4.5.4 Displaying Filtered Data in the JSP Page

4.6 Adding Login Functionality to the Application

4.6.1 Creating a Method to Authenticate Users

4.6.2 Creating a Login Page

4.6.3 Preparing Error Reports for Failed Logins

4.6.4 Creating the Login Interface

4.6.5 Creating a JSP Page to Handle Login Action

4.7 Testing the JSP Page

5 Updating Data

5.1 Creating a JavaBean

5.1.1 Creating a JavaBean in JDeveloper

5.1.2 Defining the JavaBean Properties and Methods

5.2 Updating Data from a Java Class

5.2.1 Creating a Method to Identify an Employee Record

5.2.2 Creating a Method to Update Employee Data

5.2.3 Adding a Link to Navigate to an Update Page

5.2.4 Creating a JSP Page to Edit Employee Data

5.2.5 Creating a JSP Page to Handle an Update Action

5.3 Inserting an Employee Record

5.3.1 Creating a Method to Insert Data

5.3.2 Adding a Link to Navigate to an Insert Page

5.3.3 Creating a JSP Page to Enter New Data

5.3.4 Creating a JSP Page to Handle an Insert Action

5.4 Deleting an Employee Record

5.4.1 Creating a Method for Deleting Data

5.4.2 Adding a Link to Delete an Employee

5.4.3 Creating a JSP Page to Handle a Delete Action

5.5 Exception Handling

5.5.1 Adding Exception Handling to Java Methods

5.5.2 Creating a Method for Handling Any SQLException

5.6 Navigation in the Sample Application

5.6.1 Creating a Starting Page for an Application

6 Enhancing the Application: Advanced JDBC Features

6.1 Using Dynamic SQL

6.1.1 Using OraclePreparedStatement

6.1.2 Using OracleCallableStatement

6.1.3 Using Bind Variables

6.2 Calling Stored Procedures

6.2.1 Creating a PL/SQL Stored Procedure in JDeveloper

6.2.2 Creating a Method to Use the Stored Procedure

6.2.3 Allowing Users to Choose the Stored Procedure

6.2.4 Calling the Stored Procedure from the Application

6.3 Using Cursor Variables

6.3.1 Oracle REF CURSOR Type Category

6.3.2 Accessing REF CURSOR Data

6.3.3 Using REF CURSOR in the Sample Application

6.3.3.1 Creating a Package in the Database

6.3.3.2 Creating a Database Function

6.3.3.3 Calling the REF CURSOR from a Method

6.3.3.4 Displaying a Dynamically Generated List

7 Creating a Master-Detail Application Using JPA and Oracle ADF

7.1 Overview of the Master-Detail Application

7.2 Using Java Persistence API (JPA) with Oracle ADF

7.2.1 Java Persistence API (JPA)

7.2.2 Oracle ADF Faces

7.2.3 ADF Data Controls

7.3 Building the Data Model with EJB 3.0 Using the EJB Diagramer

7.3.1 Creating an Application and Project

7.3.2 Creating the Persistence Model

7.3.3 Creating the Data Model

7.3.4 Running the Java Service outside Java EE container

7.4 Create a New Project for the User Interface

7.5 Creating the Page Flow

7.6 Creating a Master-Detail JavaServer Faces Page

7.7 Creating a Query and Edit Page

7.8 Running the Application

8 Getting Unconnected from Oracle Database

8.1 Creating a Method to Close All Open Objects

8.2 Closing Open Objects in the Application

9 Building Global Applications

9.1 Developing Locale Awareness

9.1.1 Mapping Between Oracle and Java Locales

9.2 Determining User Locales

9.2.1 Locale Awareness in Java Applications

9.3 Encoding HTML Pages

9.3.1 Specifying the Page Encoding for HTML Pages

9.3.2 Specifying the Page Encoding in Java Servlets and JSP Pages

9.4 Organizing the Content of HTML Pages for Translation

9.4.1 Strings in Java Servlets and JSP Pages

9.4.2 Static Files

9.4.3 Data from the Database

9.5 Presenting Data by User Locale Convention

9.5.1 Oracle Date Formats

9.5.2 Oracle Number Formats

9.5.3 Oracle Linguistic Sorts

9.5.4 Oracle Error Messages

9.6 Localizing Text on JSP Pages in JDeveloper

9.6.1 Creating a Resource Bundle

9.6.2 Using Resource Bundle Text on JSP Pages

Index

List of Examples

2-1 Determining the JDBC Driver Version

3-1 Specifying the url Property for the DataSource Object

3-2 Default Service Configuration in listener.ora

3-3 Importing Packages in a Java Application

3-4 Declaring Connection Variables and the Connection Object

3-5 Adding a Method to Connect to the Database

4-1 Creating a Statement Object

4-2 Declaring a Scroll-Sensitive, Read-Only ResultSet Object

4-3 Using the Connection, Statement, Query, and ResultSet Objects

4-4 Implementing User Validation

5-1 Skeleton Code for a Basic Java Bean with Accessor Methods

5-2 Method for Updating a Database Record

5-3 Method for Adding a New Employee Record

5-4 Method for Deleting an Employee Record

5-5 Adding a Method to Handle Any SQLException in the Application

6-1 Creating a PreparedStatement

6-2 Creating a CallableStatement

6-3 Calling Stored Procedures

6-4 Creating a Stored Function

6-5 Calling a Stored Function in Java

6-6 Creating a PL/SQL Stored Procedure to Insert Employee Data

6-7 Using PL/SQL Stored Procedures in Java

6-8 Declaring a REF CURSOR Type

6-9 Accessing REF Cursor Data in Java

6-10 Creating a Package in the Database

6-11 Creating a Stored Function

9-1 Mapping from a Java Locale to an Oracle Language and Territory

9-2 Determining User Locale in Java Using the Accept-Language Header

9-3 Explicitly Specifying User Locale in Java

9-4 Specifying Page Encoding in the HTTP Specification

9-5 Specifying Page Encoding on an HTML Page

9-6 Specifying Page Encoding in Servlets Using setContentType

9-7 Difference Between Date Formats by Locale (United States and Germany)

9-8 Difference Between Number Formats by Locale (United States and Germany)

9-9 Variations in Linguistic Sorting (Binary and Spanish)

9-10 Creating a Resource Bundle Class

List of Figures

1-1 JDeveloper User Interface

1-2 Web Pages in the Sample Application

3-1 Specifying Connection Details

3-2 Accessing Database Objects in the Database Navigator

3-3 Viewing the Table Structure and Data

3-4 Selecting the Class to View the Javadoc in JDeveloper

3-5 Javadoc Display in JDeveloper

3-6 Creating a Java Class

3-7 Java Source Editor

3-8 Importing Libraries

3-9 Java Code Insight

4-1 Test Output for Query Method in Log Window

4-2 Adding Content to JSP Pages in the JDeveloper Visual Source Editor

4-3 Adding Static Content to the JSP Page

4-4 useBean Representation in the employees.jsp File

4-5 Scriptlet Representation in a JSP Page

4-6 Viewing Errors in the Structure Window

4-7 Importing Packages in JDeveloper

4-8 Table in a JSP Page

4-9 HTML Form Components in the JSP Page

4-10 Using the Scriptlet Properties Dialog Box

4-11 Login Page

4-12 Login Page for Sample Application in the Browser

4-13 Unfiltered Employee Data in employee.jsp

4-14 Filtered Employee Data in employee.jsp

5-1 Generate Accessors Dialog Box

5-2 Link to Edit Employees in employees.jsp

5-3 Creating a JSP Page to Edit Employee Details

5-4 Editing Employee Data

5-5 Form to Insert Employee Data

5-6 Inserting New Employee Data

5-7 Inserting Employee Data

5-8 Link for Deleting an Employee from employees.jsp

6-1 Adding a Link to Provide the Stored Procedure Option

6-2 Using Stored Procedures to Enter Records

6-3 Structure View of Dropdown ListBox Options

6-4 Dynamically Generated List in Browser

7-1 Master Detail Application Pages

7-2 Persistence Model

7-3 Creating Java Service Facade

7-4 JSF Navigation

7-5 Master-Detail Application Viewed in a Browser

7-6 Editing the Master Detail Application Content

List of Tables

2-1 Directories and Files in the ORACLE_HOME Directory

3-1 Standard Data Source Properties

4-1 Key Query Execution Methods for java.sql.Statement

9-1 Locale Representation in Java, SQL, and PL/SQL Programming Environments

Oracle® Database

2 Day + Java Developer's Guide

11g Release 2

E12137-02

February 2012

Oracle Database 2 Day + Java Developer's Guide, 11g Release 2

E12137-02

Copyright © 2007, 2012, Oracle and/or its affiliates. All rights reserved.

Primary Authors: Deepa Aswani, Rosslynne Hefferan, Maitreyee Chaliha

Contributing Authors: Kathleen Heap, Simon Law

Contributors: Kuassi Mensah, Chris Schalk, Christian Bauwens, Mark Townsend, Paul Lo, Venkatasubramaniam Iyer

This software and related documentation are provided under a license agreement containing restrictions on use and disclosure and are protected by intellectual property laws. Except as expressly permitted in your license agreement or allowed by law, you may not use, copy, reproduce, translate, broadcast, modify, license, transmit, distribute, exhibit, perform, publish, or display any part, in any form, or by any means. Reverse engineering, disassembly, or decompilation of this software, unless required by law for interoperability, is prohibited.

The information contained herein is subject to change without notice and is not warranted to be error-free. If you find any errors, please report them to us in writing.

If this is software or related documentation that is delivered to the U.S. Government or anyone licensing it on behalf of the U.S. Government, the following notice is applicable:

U.S. GOVERNMENT RIGHTS Programs, software, databases, and related documentation and technical data delivered to U.S. Government customers are "commercial computer software" or "commercial technical data" pursuant to the applicable Federal Acquisition Regulation and agency-specific supplemental regulations. As such, the use, duplication, disclosure, modification, and adaptation shall be subject to the restrictions and license terms set forth in the applicable Government contract, and, to the extent applicable by the terms of the Government contract, the additional rights set forth in FAR 52.227-19, Commercial Computer Software License (December 2007). Oracle America, Inc., 500 Oracle Parkway, Redwood City, CA 94065.

This software or hardware is developed for general use in a variety of information management applications. It is not developed or intended for use in any inherently dangerous applications, including applications that may create a risk of personal injury. If you use this software or hardware in dangerous applications, then you shall be responsible to take all appropriate fail-safe, backup, redundancy, and other measures to ensure its safe use. Oracle Corporation and its affiliates disclaim any liability for any damages caused by use of this software or hardware in dangerous applications.

Oracle and Java are registered trademarks of Oracle and/or its affiliates. Other names may be trademarks of their respective owners.

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This software or hardware and documentation may provide access to or information on content, products, and services from third parties. Oracle Corporation and its affiliates are not responsible for and expressly disclaim all warranties of any kind with respect to third-party content, products, and services. Oracle Corporation and its affiliates will not be responsible for any loss, costs, or damages incurred due to your access to or use of third-party content, products, or services.

Preface

This Preface introduces you to Oracle Database 2 Day + Java Developer's Guide, by discussing the intended audience and conventions of this document. It also includes a list of related Oracle documents that you can refer to for more information.

Audience

This guide is intended for application developers using Java to access and modify data in Oracle Database. This guide illustrates how to perform these tasks using a simple Java Database Connectivity (JDBC) application. This guide uses the Oracle JDeveloper integrated development environment (IDE) to create the application. This guide can be read by anyone with an interest in Java programming, but it assumes at least some prior knowledge of the following:

Java

Oracle PL/SQL

Oracle databases

Documentation Accessibility

For information about Oracle's commitment to accessibility, visit the Oracle Accessibility Program website at http://www.oracle.com/pls/topic/lookup?ctx=acc&id=docacc.

Access to Oracle Support

Oracle customers have access to electronic support through My Oracle Support. For information, visit http://www.oracle.com/pls/topic/lookup?ctx=acc&id=info or visit http://www.oracle.com/pls/topic/lookup?ctx=acc&id=trs if you are hearing impaired.

Accessibility of Links to External Web Sites in Documentation

This documentation may contain links to Web sites of other companies or organizations that Oracle does not own or control. Oracle neither evaluates nor makes any representations regarding the accessibility of these Web sites.

Deaf/Hard of Hearing Access to Oracle Support Services

To reach Oracle Support Services, use a telecommunications relay service (TRS) to call Oracle Support at 1.800.223.1711. An Oracle Support Services engineer will handle technical issues and provide customer support according to the Oracle service request process. Information about TRS is available at http://www.fcc.gov/cgb/consumerfacts/trs.html, and a list of phone numbers is available at http://www.fcc.gov/cgb/dro/trsphonebk.html.

Related Documents

For more information, see the following documents in the Oracle Database documentation set:

Oracle® Fusion Middleware Installation Guide for Oracle JDeveloper, 11g Release 1 (11.1.1) and JDeveloper Online Documentation on Oracle Technology Network at

http://www.oracle.com/technetwork/developer-tools/jdev/documentation/index.html

Oracle Database JDBC Developer's Guide and Reference, 11g Release 2 (11.2)

Oracle Database Java Developer's Guide, 11g Release 2 (11.2)

Conventions

The following text conventions are used in this document:

Convention | Meaning
boldface | Boldface type indicates graphical user interface elements associated with an action, or terms defined in text or the glossary.
italic | Italic type indicates book titles, emphasis, or placeholder variables for which you supply particular values.
monospace | Monospace type indicates commands within a paragraph, URLs, code in examples, text that appears on the screen, or text that you enter.

1 Using Java with Oracle Database

Oracle Database is a relational database that you can use to store, use, and modify data. The Java Database Connectivity (JDBC) standard is used by Java applications to access and manipulate data in relational databases.

JDBC is an industry-standard application programming interface (API) developed by Sun Microsystems that lets you embed SQL statements in Java code. JDBC is based on the X/Open SQL Call Level Interface (CLI) and complies with the Entry Level of the SQL-92 standard. Each vendor, such as Oracle, creates its JDBC implementation by implementing the interfaces of the standard java.sql package.

See Also:

http://java.sun.com/javase/technologies/database/index.jsp

This guide shows you how to use a simple Java application to connect to Oracle Database and access and modify data within the database. Further, it uses the Oracle Application Development Framework (ADF) to develop a master-detail application to display employee data.

This chapter introduces you to the Java application created in this guide, and to the tools you can use to develop the Java application in the following topics:

Using Java to Connect to Oracle Database

Using JDeveloper to Create JDBC Applications

Overview of Sample Java Application

1.1 Using Java to Connect to Oracle Database

JDBC is a database access protocol that enables you connect to a database and run SQL statements and queries on the database. The core Java class libraries provide the JDBC APIs, java.sql and javax.sql. However, JDBC is designed to allow vendors to supply drivers that offer the necessary specialization for a particular database.

Note:

Oracle Database 11g Release 2 support JDK 5 and onward. The JDBC support in this release includes the ojdbc5.jar and ojdbc6.jar files. The ojdbc6.jar file offers JDBC 4.0 compliance. To use this file, you need JDK 6.

Oracle Database provides support for the client-side application development through the JDBC Thin Driver and the Oracle Call Interface (OCI) Driver, and the oracle.sql and oracle.jdbc packages. The classes and interfaces in these packages extend the JDBC standard. They allow you to access and modify Oracle data types and use Oracle performance extensions for JDBC with greater flexibility in a Java application.

The following sections describe Oracle support for the JDBC standard:

Oracle JDBC Thin Driver

Oracle JDBC OCI Driver

Oracle JDBC Packages

See Also:

Oracle Database JDBC Developer's Guide and Reference

Oracle Database Java Developer's Guide

1.1.1 Oracle JDBC Thin Driver

Oracle recommends using the JDBC Thin Driver for most requirements. JDBC-OCI is only needed for OCI-specific features.

The JDBC Thin Driver is a pure Java, Type IV driver. It supports the JavaTM 2 Platform Standard Edition 5.0, also known as Java Development Kit (JDK) 5. It also includes support for JDK 6. It is platform-independent and does not require any additional Oracle software for client-side application development. The JDBC Thin Driver communicates with the server using SQL*Net to access Oracle Database.

The JDBC Thin Driver allows a direct connection to the database by providing a pure Java implementation of Oracle network protocols (Two-Task Common, also known as the TTC protocol, and SQL*Net). The driver supports the TCP/IP protocol and requires a Transparent Network Substrate (TNS) listener on the TCP/IP sockets on the database server. The Thin driver will work on any machine that has a suitable Java virtual machine (JVM).

You can access the Oracle-specific JDBC features and the standard features by using the oracle.jdbc package.

1.1.2 Oracle JDBC OCI Driver

The JDBC OCI driver is a Type II driver used with Java applications. It requires an Oracle client installation. It supports all installed Oracle Net adapters, including interprocess communication (IPC), named pipes, TCP/IP, and InternetworkPacket Exchange/Sequenced Packet Exchange (IPX/SPX).

OCI is an API that enables you to create applications that use native procedures or function calls. The JDBC OCI driver, written in a combination of Java and C, converts JDBC calls to calls to OCI. It does this by using native methods to call C-entry points. These calls communicate with the database using SQL*Net.

1.1.3 Oracle JDBC Packages

Oracle support for the JDBC API is provided through the oracle.jdbc and oracle.sql packages. These packages support all Java Development Kit (JDK) releases from 1.5 through 1.6.

oracle.sql

The oracle.sql package supports direct access to data in SQL format. This package consists primarily of classes that provide Java mappings to SQL data types and their support classes. Essentially, the classes act as Java wrappers for SQL data. The characters are converted to Java chars and, then, to bytes in the UCS-2 character set.Each of the oracle.sql.* data type classes extends oracle.sql.Datum, a superclass that includes functions and features common to all the data types. Some of the classes are for JDBC 2.0-compliant data types. In addition to data type classes, the oracle.sql package supports classes and interfaces for use with objects and collections.

oracle.jdbc

The interfaces of the oracle.jdbc package define the Oracle extensions to the interfaces in the java.sql package. These extensions provide access to Oracle SQL-format data. They also provide access to other Oracle-specific features, including Oracle performance enhancements.

The key classes and interfaces of this package provide methods that support standard JDBC features and perform tasks such as:

Returning Oracle statement objects

Setting Oracle performance extensions for any statement

Binding oracle.sql.* types into prepared and callable statements

Retrieving data in oracle.sql format

Getting meta information about the database and result sets

Defining integer constants used to identify SQL types

See Also:

Oracle Database JDBC Developer's Guide and Reference

1.2 Using JDeveloper to Create JDBC Applications

The Java application tutorial in this guide uses Oracle JDeveloper 10g release 10.1.3 as the integrated development environment (IDE) for developing the Java application and creating Web pages for users to view and change the data.

Oracle JDeveloper is an IDE with support for modeling, developing, debugging, optimizing, and deploying Java applications and Web services.

JDeveloper provides features for you to write and test Java programs that access the database with SQL statements embedded in Java programs. For the database, JDeveloper provides functions and features to do the following:

Create a connection to a database

Browse database objects

Create, edit, or delete database objects

Create and edit PL/SQL functions, procedures, and packages

1.2.1 JDeveloper User Interface

Oracle JDeveloper is an IDE that uses windows for various application development tools. You can display or hide any of the windows, and you can dock them or undock them to create a desktop suited to your method of working.

In addition to these tools, JDeveloper provides a range of navigators to help you organize and view the contents of your projects. Application and System navigators show you the files in your projects, and a Structure window shows you the structure of individual items.

You can arrange the windows as you choose, and can close and open them from the View menu. Figure 1-1 shows the default layout of some of the available navigators, palettes, and work areas in the JDeveloper user interface (GUI).

Figure 1-1 JDeveloper User Interface

JDeveloper user interface
Description of "Figure 1-1 JDeveloper User Interface"

See Also:

Working with Windows in the IDE, in the JDeveloper online Help

1.2.2 JDeveloper Tools

For creating a Java application, JDeveloper provides the following tools to simplify the process:

Structure window, which provides a tree view of all of the elements in the application currently being edited be it Java, XML, or JSP/HTML.

Java Visual Editor, which you can use to assemble the elements of a user interface quickly and easily.

JSP/HTML Visual Editor, which you can use to visually edit HTML and JSP pages.

Java Source Editor, which provides extensive features for helping in writing the Java code, such as distinctive highlighting for syntax and semantic errors, assistance for adding and sorting import statements, the Java Code Insight feature, and code templates.

Note:

The Java Code Insight feature is a facility that provides context-specific, intelligent input when creating code in the Java Source Editor. In this guide, you will see many instances of how you can use Java Code Insight to insert code.

Component Palette, from which you select the user interface components, such as buttons and text areas, that you want to display on your pages.

Property Inspector, which gives a simple way of setting properties of items such as user interface components.

Figure 1-1 might help you get a better idea of where you can access these tools in the JDeveloper UI.

1.3 Overview of Sample Java Application

This guide shows you how to create an application using Java, JDBC and Oracle ADF. In this application, you build in the following functions and features:

Allow users to log in and validate the user name and password.

Establish a connection to the database.

Query the database for data and retrieve the data using a JavaBean.

Display the data using JavaServer Pages (JSP) technology.

Allow users to insert, update, or delete records.

Access and modify information from a master-detail application.

Handle exceptions.

Note:

The application connects to the HR schema that ships with Oracle Database. Although the Oracle Database client installation comes with both the Thin and OCI drivers, the sample application will use only the JDBC Thin Driver.

Overview of Application Web Pages (JSP Pages)

Figure 1-2 shows the relationships among the pages developed for this application.

Figure 1-2 Web Pages in the Sample Application

Description of Figure 1-2 follows
Description of "Figure 1-2 Web Pages in the Sample Application"

A brief description of the Web pages in the sample application follows:

index.jsp

This is the starting page of the application. It automatically forwards the user to the login page of the application, login.jsp.

login.jsp

This page allows users to log in to the application. The user name, password, and host information are validated and used to create the connection descriptor to log in to the database.

login_action.jsp

This is a nonviewable page that handles the authentication of the user-supplied login details from login.jsp. If authentication is successful, the page forwards the user to employees.jsp. Otherwise, it redisplays the login.jsp page including a message.

employees.jsp

This is the main page of the application. It displays a list of all the employees in the HR schema for AnyCo Corporation and allows the user to filter the list of employees using any string. It also includes links to add, edit, and delete any user data. These actions, however, are handled by other JSP pages that are created specifically for each of these tasks.

insert.jsp

The link to insert employee data on the employees.jsp page redirects the user to this page. This includes a form that accepts all the details for a new employee record. The details entered on this form are processed by the insert_action.jsp page.

insert_action.jsp

This is a nonviewable page that handles the insertion of data for a new employee that is entered on the insert.jsp page.

edit.jsp

The link to edit employee data on the employees.jsp page redirects the user to this page. This form displays current data of a single employee in text fields, and the user can edit this information.

update_action.jsp

The submit action on the edit.jsp page directs the data to this nonviewable page, which inserts the edited data into the database.

delete_action.jsp

The link to delete an employee record on the employees.jsp page is handled by this nonviewable page, which deletes the employee data and forwards the user back to the employees.jsp page.

Classes

The sample application includes the following classes:

DataHandler.java

This class contains all the methods that are used to implement the important functions of the sample application. It includes methods that validate user credentials, connect to the database, retrieve employee data with and without filters, insert data, update data, handle exceptions, and so on.

Employees.java

This class is a JavaBean that holds a single employee record. It contains accessor methods to get and set the values of each of the record fields. It also contains accessor methods to retrieve and modify employee records.

JavaClient.java

This class is used only for testing the DataHandler class.

Note:

This application is developed throughout this guide in the form of a tutorial. It is recommended, therefore, that you read these chapters in sequence.

1.4 Advanced Application Development Using Developer Frameworks

To develop enterprise solutions that search, display, create, modify, and validate data using web, wireless, desktop, or web services interfaces, you need to use developer frameworks to simplify your job.

Using frameworks, developers can write code based on well-defined interfaces. This is largely a time-saving benefit, but it also makes sense in a Java EE environment because Java EE frameworks provide the necessary infrastructure for the enterprise application. In other words, Java EE frameworks make the concepts expressed in the Java EE design patterns more concrete.

The Oracle Application Development Framework (Oracle ADF) is such an end-to-end application framework that builds on Java EE standards and open-source technologies to simplify and accelerate implementing service-oriented applications.

To illustrate how application development can be made easy using a feature-rich environment that facilitates the creation of complex applications, this guide includes a master-detail application in Chapter 7.

2 Getting Started with the Application

To develop a Java application that connects to Oracle Database, you need to ensure that certain components are installed as required. This chapter covers the following topics:

What You Need to Install

Verifying the Oracle Database Client Installation

Installing Oracle JDeveloper

2.1 What You Need to Install

To be able to develop the sample application, you need to install the following products and components:

Oracle Database Server

Oracle Database Client

J2SE or JDK

Integrated Development Environment

Web Server

The following subsections describe these requirements in detail.

2.1.1 Oracle Database Server

To develop the Java application, you need a working installation of Oracle Database Server with the HR schema, which comes with the database. If you choose to install the client, then you must install the Oracle Database Server before the Oracle Database Client installation. The installation creates an instance of Oracle Database and provides additional tools for managing this database. The server installation is platform-specific. For more information, refer to the Oracle Database Installation Guide.

2.1.1.1 Modifying the HR Schema for the JDBC Application

The HR user account, which owns the sample HR schema used for the Java application in this guide, is initially locked. You must log in as a user with administrative privileges (SYS) and unlock the account before you can log in as HR.

If the database is locally installed, use the command prompt or console window to unlock the account as follows:

Log in to SQL*Plus as a user with DBA privileges, for example:

> SQLPLUS SYS/ AS SYSDBA
Enter password: password

Run the following command:

> PASSWORD HR
Changing password for HR
New password: password
Retype new password: password

Test the connection as follows:

> CONNECT HR
Enter password: password

You should see a message indicating that you have connected to the database.

Note:

For information on creating and using secure passwords with Oracle Database, refer to Oracle Database Security Guide.

In addition, some of the constraints and triggers present in the HR schema are not in line with the scope of the Java application created in this guide. You must remove these constraints and triggers as follows using the following SQL statements:

DROP TRIGGER HR.UPDATE_JOB_HISTORY;
DROP TRIGGER HR.ADD_JOB_HISTORY;
DROP TRIGGER HR.SECURE_EMPLOYEES;
ALTER TABLE EMPLOYEES  DROP CONSTRAINT JHIST_EMP_FK;
DELETE FROM JOB_HISTORY;

2.1.2 Oracle Database Client

Oracle Database Client installation is optional, but recommended. Installing Oracle Database Client on any computer allows easy access from that system to the Oracle Database. The installation also includes the following development tools:

Oracle JDBC drivers

Oracle Open Database Connectivity (ODBC) driver

Oracle Provider for OLE DB

Oracle Data Provider for .NET (ODP.NET)

Oracle Services for Microsoft Transaction Server

The client installation is platform-specific. Refer to the following Oracle Database Client installation guides for more information on installing the client:

Oracle Database Client Installation Guide 11g Release 2 (11.2) for Linux

Oracle Database Client Installation Guide 11g Release 2 (11.2) for Microsoft Windows

2.1.3 J2SE or JDK

To create and compile Java applications, you need the full Java 2 Platform, Standard Edition, Software Development Kit (J2SE SDK), formerly known as the Java Development Kit (JDK). To create and compile applications that access databases, you must have the full JDBC API that comes with J2SE. This download also includes the Java Runtime Environment (JRE).

Note:

Oracle Database does not support JDK 1.2, JDK 1.3, JDK 1.4, and all classes12*.* files. You need to use the ojdbc5.jar and the ojbc6.jar files with JDK 5.n and JDK 6.n, respectively.

The oracle.jdbc.driver.* classes, the ojdbc4.jar file, and the OracleConnectionCacheImpl class are no longer supported or available.

JDK versioning conventions have changed from JDK version 1.n to JDK n. Refer to the Sun Java site at the following location for more information:

http://java.sun.com/j2se/1.5.0/docs/relnotes/version-5.0.html

See Also:

http://java.sun.com/javase/index.jsp for information on installing Java

http://java.sun.com/javase/technologies/database.jsp for information on the JDBC API

2.1.4 Integrated Development Environment

For ease in developing the application, you can choose to develop your application in an integrated development environment (IDE). This guide uses Oracle JDeveloper to create the files for this application. For more information on installing JDeveloper, refer to Installing Oracle JDeveloper.

2.1.5 Web Server

The sample application developed in this guide uses JavaServer Pages (JSP) technology to display information and accept input from users. To deploy these pages, you need a Web server with a servlet and JSP container, such as the Apache Tomcat application server.

This guide uses the embedded server called the Oracle WebLogic Server in JDeveloper for deploying the JSP pages. If you choose not to install Oracle JDeveloper, then any Web server that allows you to deploy JSP pages should suffice.

JDeveloper supports direct deployment to the following production application servers:

Oracle WebLogic Server

Oracle Application Server

Apache Tomcat

IBM WebSphere

JBoss

For more information about these servers, please refer to vendor-specific documentation.

2.2 Verifying the Oracle Database Client Installation

Oracle Database client installation is platform-specific. You need to verify that the client installation was successful before you proceed to create the sample application. This section describes the steps for verifying an Oracle Database client installation.

Verifying a client installation involves the following tasks:

Checking Installed Directories and Files

Checking the Environment Variables

Determining the JDBC Driver Version

2.2.1 Checking Installed Directories and Files

Installing Oracle Java products creates the following directories:

ORACLE_HOME/jdbc

ORACLE_HOME /jlib

Check if the directories described in Table 2-1 have been created and populated in the ORACLE_HOME directory.

Table 2-1 Directories and Files in the ORACLE_HOME Directory

Directory
Description

/jdbc/lib

The lib directory contains the ojdbc5.jar and ojdbc6.jar required Java classes. These contain the JDBC driver classes for use with JDK 5 and JDK 6.

/jdbc/Readme.txt

This file contains late-breaking and release-specific information about the drivers, which may not have been included in other documentation on the product.

/jlib

This directory contains the orai18n.jar file. This file contains classes for globalization and multibyte character sets support.

Note:

These files can also be obtained from the Sun Microsystems Web site. However, it is recommended to use the files supplied by Oracle, which have been tested with the Oracle drivers.

2.2.2 Checking the Environment Variables

This section describes the environment variables that must be set for the JDBC Thin Driver. You must set the classpath for your installed JDBC Thin Driver. For JDK 5, you must set the following values for the CLASSPATH variable:

ORACLE_HOME/jdbc/lib/ojdbc5.jar
ORACLE_HOME/jlib/orai18n.jar

Ensure that there is only one JDBC class file, such as ojdbc6.jar, and one globalization classes file, orai18n.jar, in the CLASSPATH variable.

2.2.3 Determining the JDBC Driver Version

Starting from Oracle Database 11g Release 1, you can get details about the JDBC support in the database as follows:

> java -jar ojdbc6.jar
  Oracle 11.1.0.0. JDBC 4.0 compiled with JDK6

In addition, you can determine the version of the JDBC driver that you installed by calling the getDriverVersion method of the OracleDatabaseMetaData class.

Note:

The JDBC Thin Driver requires a TCP/IP listener to be running on the computer where the database is installed.

Example 2-1 illustrates how to determine the driver version:

Example 2-1 Determining the JDBC Driver Version

import java.sql.*;
import oracle.jdbc.*;
import oracle.jdbc.pool.OracleDataSource;

class JDBCVersion
{
  public static void main (String args[]) throws SQLException
  {
    OracleDataSource ods = new OracleDataSource();
    ods.setURL("jdbc:oracle:thin:hr/hr@localhost:1521/XE");
    Connection conn = ods.getConnection();

    // Create Oracle DatabaseMetaData object
    DatabaseMetaData meta = conn.getMetaData();

    // gets driver info:
    System.out.println("JDBC driver version is " + meta.getDriverVersion());
  }
}

2.3 Installing Oracle JDeveloper

In this guide, the integrated development environment (IDE) that is used to create the sample Java application using JDBC is Oracle JDeveloper release 11.1.1. This release of JDeveloper is supported on the Microsoft Windows Vista, Windows XP, Windows 2003, Windows 2000, Linux, and Mac OS X operating systems. Installation of JDeveloper is described in detail in Installation Guide for Oracle JDeveloper Release 11.1.1.0.0, which is available online on the Oracle Technology Network at

http://download.oracle.com/docs/cd/E12839_01/install.1111/e13666/toc.htm

This guide gives a detailed description of the JDeveloper system requirements, and all the details about installing JDeveloper on the supported platforms. You should also read JDeveloper 11g Release Notes, which is available online on the Oracle Technology Network at

http://www.oracle.com/technology/products/jdev/htdocs/11/index.html

2.3.1 JDeveloper Studio Edition: Base Installation and Full Installation

JDeveloper 11.1.1 is available in two editions. The Studio Edition includes Oracle ADF, which is required for developing the master-detail application created in this guide.

You can install either the base installation or the full installation of the JDeveloper Studio Edition. In addition to JDeveloper, the full installation includes the required version of Java, the specialized Oracle Java Virtual Machine for JDeveloper (OJVM), and the online documentation, so the download file size is larger. For quicker downloading, you can install the JDeveloper base installation.

2.3.2 Steps to Install JDeveloper

If you are installing the base installation, you need to have J2EE version 1.6.0_05 on your machine. If you are installing the full installation, then J2EE is included. In outline, the installation process is as follows:

Download JDeveloper version 11.1.1 Studio Edition from the Oracle Technology Network at

http://www.oracle.com/technology/software/products/jdev/htdocs/soft11.html

Download the base installation (jdevjavabase11110.zip), or the full installation (jdevstudio11110install.exe ). It is recommended that you download the Studio Edition to avail all features.

To launch the installer for the base installation, enter the following command at the command line:

java -jar jdevstudio11110install.jar

To launch the installer for the full installation, double click jdevstudio11110install.exe and follow the instructions.

Note:

When choosing the Middleware Home directory, ensure that you choose a directory that does not contain spaces. For example, do not use C:\Program Files as the Middleware Home.

To change a JDK location that you have previously specified, you have to modify the jdev.conf file. Set the variable SetJavaHome in the file <install_dir>/jdeveloper/jdev/bin/jdev.conf to the location of your Java installation. Here, Middleware Home directory has been represented by <install_dir>.For example, in a UNIX environment, if the location of your JDK is in a directory called /usr/local/java, your entry in jdev.conf would be as follows:

SetJavaHome /usr/local/java

Other tasks that you must perform include setting the permissions for all JDeveloper files to read, and giving all users write and execute permissions to files in a range of JDeveloper directories.

If you are using the base installation, there are some additional setup tasks, such as setting the location of your Java installation in the JDeveloper configuration file, optionally installing OJVM, and downloading the online documentation so that it is locally available.

See Also:

http://download.oracle.com/docs/cd/E12839_01/install.1111/e13666/toc.htm for the JDeveloper Installation Guide

2.3.3 Starting JDeveloper

To start JDeveloper on Windows, click on Start, select All Programs, then select Oracle Fusion Middleware and select JDeveloper Studio 11.1.1.0.0. You can also run the <install_dir>\jdeveloper\jdev\bin\jdevw.exe file. To use a console window for displaying internal diagnostic information, run the jdev.exe file in the same directory instead of jdevw.exe.

To start JDeveloper on other platforms, run the <install_dir>/jdeveloper/jdev/bin/jdev file.

3 Connecting to Oracle Database

This chapter is the first in a series of five chapters, each of which describes how to create parts of a Java application that accesses Oracle Database and displays, modifies, deletes, and updates data on it. To be able to access the database from a Java application, you must connect to the database using a java.sql.Connection object.

This chapter includes the following sections:

Connecting to Oracle Database from JDeveloper

Setting Up Applications and Projects in JDeveloper

Connecting to Oracle Database from a Java Application

3.1 Connecting to Oracle Database from JDeveloper

You can set up and manage database connections in JDeveloper to enable your application to communicate with external data sources, including Oracle Database and offline database objects. This is done using the Database Navigator. The same navigator is also used to manage other connections your application needs, such as connections to application servers. The following subsections describe how you can use the Database Navigator to view the database and its objects and to create a connection to the database:

JDeveloper Database Navigator

Creating a Database Connection

Browsing the Data Using the Database Navigator

3.1.1 JDeveloper Database Navigator

The Database Navigator displays all currently defined connections. To view the Database Navigator, select the Database Navigator tab in the navigator panel on the top left-hand side of the JDeveloper display, if it is displayed, or use the View menu. For an illustration of the default layout of the JDeveloper IDE, see Figure 1-1.

You can use the Database Navigator to browse through the connections it displays. In particular, for a database schema, you can also view database objects, tables, views, and their contents.

Database connections are shown under the IDE Connections node. To view the objects in the database, expand the connection. Expanding a schema displays nodes for the object types in that schema. Expanding the node for an object type displays its individual objects. When you expand a table node, you can view the structure of the table and the data within the table.

3.1.2 Creating a Database Connection

You can connect to any database for which you have connection details. When you create a database connection, you must specify a user name and a password. By default, the connection allows you to browse only the schema of the user that you specify in the connection.

To create a connection, follow these steps:

Start JDeveloper.

From the View menu select Database Navigator. The Database Navigator is displayed, showing you a list of available connections.

Right-click IDE Connection, and from the shortcut menu, select New Connection. The Create Database Connection screen is displayed.

On the Connection screen, do not change the default values for the connection name and type, Connection1 and Oracle (JDBC). Enter HR in both the Username and Password fields. Do not enter a value for Role, and select Deploy Password. You must provide information about the computer where your database is located. Your database administrator should provide you with this information.

Enter the following information:

Driver: thin

Host Name: Host name of the computer where Oracle Database is installed

If database is on the same computer, then for the Host Name parameter, enter localhost.

JDBC Port: 1521

SID: ORCL

Click Test Connection. If the connection is successful, the word Success! is displayed in the Status field.

Figure 3–1 shows the Connection screen where you enter these details.

Figure 3-1 Specifying Connection Details

Description of Figure 3-1 follows
Description of "Figure 3-1 Specifying Connection Details"

Click Finish to create the connection and close the screen.

Disconnecting and Reconnecting from Oracle Database in JDeveloper

To disconnect from the database in JDeveloper, in the Database Navigator, right-click the connection name and select Disconnect. The display in the Database Navigator now shows only the name of the connection, without the plus (+) symbol for expanding the node. To reconnect to the database, right-click the connection name and select Connect.

3.1.3 Browsing the Data Using the Database Navigator

After you have successfully established a connection to the database, you can browse its contents through the Database Navigator. The Database Navigator displays a navigable, hierarchical tree structure for the database, its objects, their instances, and the contents of each. To view the contents at each level of the hierarchy of the database connection that you created, do the following:

The IDE Connections node in the Database Navigator now shows a node with the name of your connection. Click the plus symbol (+) to the left of the connection name to expand the navigation tree. To display a list of the instances of an object type, for example Tables, expand the Table navigation tree.

The Structure window below the navigator shows the detailed structure of any object selected in the navigator. Select a table in the navigator (for example Employees) to see the columns of that table in the Structure window.

Figure 3-2 Accessing Database Objects in the Database Navigator

Description of Figure 3-2 follows
Description of "Figure 3-2 Accessing Database Objects in the Database Navigator"

Figure 3-3 Viewing the Table Structure and Data

Description of Figure 3-3 follows
Description of "Figure 3-3 Viewing the Table Structure and Data"

If you double-click a table in the navigator, the structure of that table is displayed in the main editing area of the window. It includes details about all the columns, such as Name, Type, and Size, so you can browse the table definition.

To view the data from a table, select the Data tab below the table structure. You can now view and browse through the table data.

You can also edit the objects in the Database Navigator. To edit a table, right-click the table and select Edit from the shortcut menu. A dialog box allows you to make changes to the selected table.

3.2 Setting Up Applications and Projects in JDeveloper

In JDeveloper, you create your work in an application, within which you can organize your work into a number of projects. JDeveloper provides a number of application templates, to help you to create the project structure for standard types of application relatively quickly and easily. At the time you create your application in JDeveloper, you can choose the application template that matches the type of application you will be building.

The application template you select determines the initial project structure (the named project folders within the application) and the application technologies that will be included. You can then add any extra libraries or technologies you need for your particular application, and create additional projects if you need them.

3.2.1 Using the JDeveloper Application Navigator

The Application Navigator displays all your applications and projects. When you first start JDeveloper, the Application Navigator is displayed by default on the left side of the JDeveloper IDE.

To view the Application Navigator when it is not displayed, you can click the Applications tab in the navigator panel on the top left-hand side of the JDeveloper display, or select Application Navigator from the View menu.

The Application Navigator shows a logical grouping of the items in your projects. To see the structure of an individual item, you can select it and the structure is displayed in the Structure window.

From the Application Navigator, you can display items in an appropriate default editor. For example, if you double-click a Java file, the file opens in the Java Source Editor, and if you double-click a JavaServer Pages (JSP) file, it opens in the JSP/HTML Visual Editor.

3.2.2 Creating an Application and a Project

To get started with JDeveloper, you must create an application and at least one project in which to store your work, as follows:

In the Application Navigator, click on New Application.

The Create Generic Application wizard is displayed. Enter HRApp in the Application Name field, and from the Application Template list, select Generic Application. Click Next.

On the Name your Generic project screen, enter view as the name of the project. Click Finish.

The new HRApp application is displayed in the Application Navigator.

Save your application. To do this, from the File menu, select Save All.

3.2.3 Viewing the Javadoc and Source Code Available in the Project Scope

You can view the Javadoc or the code for any of the classes available in the project technology scope within JDeveloper. In addition, you can view the details of all the methods available for those classes.

For example, to see the code or Javadoc for the Connection class, do the following:

With your project selected in the Application Navigator, from the Navigate menu select Go to Java Class. You can also do this for a specific file in your project.

In the Go to Java Class dialog box, select Source or Javadoc.

Enter the name of the class you want to view in the Name field, or click Browse to find the class. For the Connection class, start to enter Connection, and from the displayed list select Connection (java.sql).

Figure 3-4 Selecting the Class to View the Javadoc in JDeveloper

Description of Figure 3-4 follows
Description of "Figure 3-4 Selecting the Class to View the Javadoc in JDeveloper"

Click OK.

Figure 3-5 Javadoc Display in JDeveloper

Description of Figure 3-5 follows
Description of "Figure 3-5 Javadoc Display in JDeveloper"

3.3 Connecting to Oracle Database from a Java Application

So far, you have seen how to connect to the database from JDeveloper. To initiate a connection from the Java application, you use the Connection object from the JDBC application programming interface (API).

This section describes connecting to the database from the Java application in the following subsections:

Overview of Connecting to Oracle Database

Specifying Database URLs

Creating a Java Class in JDeveloper

Java Libraries

Adding JDBC and JSP Libraries

Importing JDBC Packages

Declaring Connection-Related Variables

Creating the Connection Method

3.3.1 Overview of Connecting to Oracle Database

In Java, you use an instance of the DataSource object to get a connection to the database. The DataSource interface provides a complete replacement for the previous JDBC DriverManager class. Oracle implements the javax.sql.DataSource interface with the OracleDataSource class in the oracle.jdbc.pool package. The overloaded getConnection method returns a physical connection to the database.

Note:

The use of the DriverManager class to establish a connection to a database is deprecated.

You can either set properties using appropriate setxxx methods for the DataSource object or use the getConnection method that accepts these properties as input parameters.

Important DataSource Properties are listed in Table 3-1.

Table 3-1 Standard Data Source Properties

Name
Type
Description

databaseName

String

Name of the particular database on the server. Also known as the service name (or SID) in Oracle terminology. For Oracle Database, this is ORCL by default.

dataSourceName

String

Name of the underlying data source class.

description

String

Description of the data source.

networkProtocol

String

Network protocol for communicating with the server. For Oracle, this applies only to the JDBC Oracle Call Interface (OCI) drivers and defaults to tcp.

password

String

Password for the connecting user.

portNumber

int

Number of the port where the server listens for requests

serverName

String

Name of the database server

user

String

User name to be used for login

driverType

String

Specifies the Oracle JDBC driver type. It can be either oci or thin.

This is an Oracle-specific property.

url

String

Specifies the URL of the database connect string.You can use this property in place of the standard portNumber, networkProtocol, serverName, and databaseName properties.

This is an Oracle-specific property.

If you choose to set the url property of the DataSource object with all necessary parameters, then you can connect to the database without setting any other properties or specifying any additional parameters with the getDBConnection method. For more information on setting the database URL, refer to the Specifying Database URLs section.

Note:

The parameters specified through the getConnection method override all property and url parameter settings previously specified in the application.

See Also:

Oracle Database JDBC Developer's Guide and Reference

3.3.2 Specifying Database URLs

This release of Oracle JVM supports Internet Protocol Version 6 (IPv6) addresses in the URL and machine names of the Java code in the database, which resolve to IPv6 addresses.

Database URLs are strings that you specify for the value of the url property of the DataSource object. The complete URL syntax is the following:

jdbc:oracle:driver_type:[username/password]@database_specifier

The first part of the URL specifies which JDBC driver is to be used. The supported driver_type values for client-side applications are thin and oci. The brackets indicate that the user name and password pair is optional. The database_specifier value identifies the database to which the application is connected.

The following is the syntax for thin-style service names that are supported by the Thin driver:

jdbc:oracle:driver_type:[username/password]@//host_name:port_number:SID

For the sample application created in this guide, if you include the user name and password, and if the database is hosted locally, then the database connection URL is as shown in Example 3-1.

Example 3-1 Specifying the url Property for the DataSource Object

jdbc:oracle:thin:hr/hr@localhost:1521:UORCL

3.3.2.1 Using the Default Service Feature of the Oracle Database Client

Oracle Database comes with a new connection feature. If you install the Oracle Database client, then you need not specify all the details in the database specifier part of the connection URL. Under certain conditions, the Oracle Database connection adapter requires only the host name of the computer where the database is installed.

Because of this feature introduced in Oracle Database, some parts of the JDBC connection URL syntax become optional:

jdbc:oracle:driver_type:[username/password]@[//]host_name[:port][:ORCL]

In this URL:

// is optional.

:port is optional.

Specify a port only if the default Oracle Net listener port (1521) is not used.

:ORCL (or the service name) is optional.

The connection adapter for the Oracle Database Client connects to the default service on the host. On the host, this is set to ORCL in the listener.ora file.

Example 3-2 shows a basic configuration of the listener.ora file, where the default service is defined.

Example 3-2 Default Service Configuration in listener.ora

MYLISTENER = (ADDRESS_LIST=
 (ADDRESS=(PROTOCOL=tcp)(HOST=test555)(PORT=1521))
)
DEFAULT_SERVICE_MYLISTENER=dbjf.regress.rdbms.dev.testserver.com

SID_LIST_MYLISTENER = (SID_LIST=
(SID_DESC=(SID_NAME=dbjf)(GLOBAL_DBNAME=dbjf.regress.rdbms.dev.testserver.com)(ORACLE_HOME=/test/oracle))
)

After making changes to the listener.ora file, you must restart the listener with the following command:

> lsnrctl start mylistener

The following URLs should work with this configuration:

jdbc:oracle:thin:@//test555.testserver.com
jdbc:oracle:thin:@//test555.testserver.com:1521
jdbc:oracle:thin:@test555.testserver.com
jdbc:oracle:thin:@test555.testserver.com:1521
jdbc:oracle:thin:@(DESCRIPTION=(ADDRESS=(PROTOCOL=TCP)(HOST=test555.testserver.com)(PORT=1521)))
jdbc:oracle:thin:@(DESCRIPTION=(ADDRESS=(PROTOCOL=TCP)(HOST=test555.testserver.com)))
jdbc:oracle:thin:@(DESCRIPTION=(ADDRESS=(PROTOCOL=TCP)(HOST=test555.testserver.com)(PORT=1521))(CONNECT_DATA=(SERVICE_NAME=)))

Note:

Default service is a new feature in Oracle Database 11g Release 1. If you use any other version of the Oracle Database Client to connect to the database, then you must specify the SID and port number.

3.3.3 Creating a Java Class in JDeveloper

The first step in building a Java application is to create a Java class. The following instructions describe how you create a class called DataHandler, which will contain the methods for querying the database and modifying the data in it.

In the Application Navigator, right-click the View project, and from the shortcut menu, select New.

In the New Gallery, select the General category. In the Items list, select Java Class, and click OK. The Create Java Class dialog box is displayed.

In the Create Java Class dialog box, enter DataHandler as the class Name, and hr as the Package. Do not change the default values of the Optional Attributes, and click OK. The Create Java Class dialog box with the appropriate values specified is shown in Figure 3-6.

Figure 3-6 Creating a Java Class

Description of Figure 3-6 follows
Description of "Figure 3-6 Creating a Java Class"

The skeleton DataHandler class is created and is displayed in the Java Source Editor. The package declaration, the class declaration, and the default constructor are created by default. Figure 3-7 shows the class displayed in the Java Source Editor, ready for you to add your Java code:

Figure 3-7 Java Source Editor

Description of Figure 3-7 follows
Description of "Figure 3-7 Java Source Editor"

3.3.4 Java Libraries

Oracle JDeveloper comes with standard libraries to help Java application programming. These libraries include API support for Application Development Framework (ADF), Oracle libraries for JDBC, JSP, and so on.

To use JDBC in your project, you import the Oracle JDBC library into the project. Similarly, to use JSP technology, you import the JSP Runtime library.

3.3.4.1 Overview of the Oracle JDBC Library

Important packages of the Oracle JDBC library include the following:

oracle.jdbc: The interfaces of the oracle.jdbc package define the Oracle extensions to the interfaces in the java.sql package. These extensions provide access to Oracle SQL-format data and other Oracle-specific features, including Oracle performance enhancements.

oracle.sql: The oracle.sql package supports direct access to data in SQL format. This package consists primarily of classes that provide Java mappings to SQL data types and their support classes.

oracle.jdbc.pool: This package includes the OracleDataSource class that is used to get a connection to the database. The overloaded getConnection method returns a physical connection to the database.

3.3.4.2 Overview of the JSP Runtime Library

This library includes the classes and tag libraries required to interpret and run JSP files on the Oracle WebLogic Server that comes with JDeveloper.

3.3.5 Adding JDBC and JSP Libraries

To include libraries in your project, perform the following steps:

Double-click the View project in the Application Navigator to display the Project Properties dialog box.

Click Libraries and Classpath, and then click Add Library. The Add Library dialog box is displayed with a list of the available libraries for the Java2 Platform, Standard Edition (J2SE) version is displayed.

In the Add Library dialog box, scroll through the list of libraries in the Extension folder. Select the JSP Runtime library and click OK to add it to the list of selected libraries for your project. Similarly, add the Oracle JDBC library. Figure 3-8 shows the Oracle JDBC library added to the view project.

Figure 3-8 Importing Libraries

Description of Figure 3-8 follows
Description of "Figure 3-8 Importing Libraries"

Click OK.

3.3.6 Importing JDBC Packages

To use JDBC in the Java application, import the following JDBC packages:

If the DataHandler.java class is not already open in the Java Source Editor, in the Application Navigator, expand the View project, Application Sources, and your package (hr) and double-click DataHandler.java.

At the end of the generated package declaration, on a new line, enter the import statements shown in Example 3-3.

Example 3-3 Importing Packages in a Java Application

package hr;
import java.sql.Connection;
import oracle.jdbc.pool.OracleDataSource;

3.3.7 Declaring Connection-Related Variables

Connection information is passed to the connection method by using the following connection variables: the connection URL, a user name, and the corresponding password.

Use the Java Source Editor of JDeveloper to edit the DataHandler.java class as follows:

After the DataHandler constructor, on a new line, declare the three connection variables as follows:

String jdbcUrl = null;
String userid = null;
String password = null;

These variables will be used in the application to contain values supplied by the user at login to authenticate the user and to create a connection to the database. The jdbcUrl variable is used to hold the URL of the database that you will connect to. The userid and password variables are used to authenticate the user and identify the schema to be used for the session.

Note:

The login variables have been set to null to secure the application. At this point in the guide, application login functionality is yet to be built into the application. Therefore, to test the application until login functionality is built in, you can set values in the login variables as follows:

Set the jdbcUrl variable to the connect string for your database.

String jdbcUrl = "jdbc:oracle:thin:@localhost:1521:ORCL";

Set the variables userid and password to hr as follows:

String userid = "hr";
String password = "hr";

Make sure you reset these to null as soon as you finish testing.

For more information on security features and practices, refer to Oracle Database Security Guide and the vendor-specific documentation for your development environment.

On a new line, declare a connection instance as follows:

Connection conn;

Your Java class should now contain the code in Example 3-4.

Example 3-4 Declaring Connection Variables and the Connection Object

package hr;
import java.sql.Connection;
import oracle.jdbc.pool.OracleDataSource;

public class DataHandler {
    public DataHandler() {
    }
    String jdbcUrl = null;
    String userid = null;
    String password = null;
    Connection conn;
}

3.3.8 Creating the Connection Method

To connect to the database, you must create a method as follows:

Add the following method declaration after the connection declaration:

public void getDBConnection() throws SQLException

The Java Code Insight feature displays a message reminding you to import the SQLException error handling package. Press the Alt+Enter keys to import it. The import java.sql.SQLException statement is added to the list of import packages.

At the end of the same line, add an open brace ({) and then press the Enter key. JDeveloper automatically creates the closing brace, and positions the cursor in a new empty line between the braces.

On a new line, declare an OracleDataSource instance as follows:

OracleDataSource ds;

Enter the following to create a new OracleDataSource object:

ds = new OracleDataSource();

Start to enter the following to set the URL for the DataSource object:

ds.setURL(jdbcUrl);

Java Code Insight prompts you by providing you with a list of available OracleDataSource methods. Scroll through the list to select the setURL(String) method, and press the Enter key to select it into your code. In the parentheses for this function, enter jdbcUrl.

Figure 3-9 shows how the Java Code Insight feature in JDeveloper helps you with inserting code.

Figure 3-9 Java Code Insight

Description of Figure 3-9 follows
Description of "Figure 3-9 Java Code Insight"

On the next line, enter the following:

conn = ds.getConnection(userid,password);

As usual, Java Code Insight will prompt you with a list of methods for ds. This time, select getConnection(String,String). In the parentheses, enter userid,password. End the line with a semicolon (;).

Your code should look similar to the code in Example 3-5.

Example 3-5 Adding a Method to Connect to the Database

package hr;
import java.sql.Connection;
import java.sql.SQLException;

import oracle.jdbc.pool.OracleDataSource;

public class DataHandler {
    public DataHandler() {
    }
    String jdbcUrl = null;
    String userid = null;
    String password = null;
    Connection conn;
    public void getDBConnection() throws SQLException{
        OracleDataSource ds;
        ds = new OracleDataSource();
        ds.setURL(jdbcUrl);
        conn=ds.getConnection(userid,password);

    }
}

Compile your class to ensure that there are no syntax errors. To do this, right-click in the Java Source Editor, and select Make from the shortcut menu. A Successful compilation message is displayed in the Log window below the Java Source Editor window.

4 Querying for and Displaying Data

This chapter adds functions and code to the DataHandler.java file for querying the database. This chapter has the following sections:

Overview of Querying for Data in Oracle Database

Querying Data from a Java Application

Creating JSP Pages

Adding Dynamic Content to the JSP Page: Database Query Results

Filtering a Query Result Set

Adding Login Functionality to the Application

Testing the JSP Page

4.1 Overview of Querying for Data in Oracle Database

In outline, to query Oracle Database from a Java class to retrieve data, you must do the following:

Create a connection by using the OracleDataSource.getConnection method. This is covered in Chapter 3, "Connecting to Oracle Database".

Define your SQL statements with the methods available for the connection object. The createStatement method is used to define a SQL query statement.

Using the methods available for the statement, run your queries. You use the executeQuery method to run queries on the database and produce a set of rows that match the query conditions. These results are contained in a ResultSet object.

You use a ResultSet object to display the data in the application pages.

The following sections describe important Java Database Connectivity (JDBC) concepts related to querying the database from a Java application:

SQL Statements

Query Methods for the Statement Object

Result Sets

See Also:

Oracle Database JDBC Developer's Guide and Reference

4.1.1 SQL Statements

Once you connect to the database and, in the process, create a Connection object, the next step is to create a Statement object. The createStatement method of the JDBC Connection object returns an object of the JDBC Statement type. Example 4-1 shows how to create a Statement object.

Example 4-1 Creating a Statement Object

Statement stmt = conn.createStatement();

The Statement object is used to run static SQL queries that can be coded into the application.

In addition, for scenarios where many similar queries with differing update values must be run on the database, you use the OraclePreparedStatement object, which extends the Statement object. To access stored procedures on Oracle Database, you use the OracleCallableStatement object.

See Also:

Using OraclePreparedStatement

Using OracleCallableStatement

Oracle Database JDBC Developer's Guide and Reference

4.1.2 Query Methods for the Statement Object

To run a query embedded in a Statement object, you use variants of the execute method. Important variants of this method are listed in Table 4-1.

Table 4-1 Key Query Execution Methods for java.sql.Statement

Method Name
Return Type
Description

execute(String sql)

Boolean

Runs the given SQL statement, which returns a Boolean response: true if the query runs successfully and false if it does not.

addBatch()

void

Adds a set of parameters to a PreparedStatement object batch of commands.

executeBatch()

int[]

Submits a batch of commands to the database for running, and returns an array of update counts if all commands run successfully.

executeQuery(String sql)

ResultSet

Runs the given SQL statement, which returns a single ResultSet object.

executeUpdate(String sql)

int

Runs the given SQL statement, which may be an INSERT, UPDATE, or DELETE statement or a SQL statement that returns nothing, such as a SQL DDL statement.

See Also:

http://java.sun.com/j2se/1.5.0/docs/api/index.html

4.1.3 Result Sets

A ResultSet object contains a table of data representing a database result set, which is generated by executing a statement that queries the database.

A cursor points to the current row of data in a ResultSet object. Initially, it is positioned before the first row. You use the next method of the ResultSet object to move the cursor to the next row in the result set. It returns false when there are no more rows in the ResultSet object. Typically, the contents of a ResultSet object are read by using the next method within a loop until it returns false.

The ResultSet interface provides accessor methods (getBoolean, getLong, getInt, and so on) for retrieving column values from the current row. Values can be retrieved by using either the index number of the column or the name of the column.

By default, only one ResultSet object per Statement object can be open at the same time. Therefore, to read data from multiple ResultSet objects, you must use multiple Statement objects. A ResultSet object is automatically closed when the Statement object that generated it is closed, rerun, or used to retrieve the next result from a sequence of multiple results.

See Also:

http://java.sun.com/j2se/1.3/docs/guide/jdbc/getstart/mapping.html for more information on mapping SQL types and Java types

Oracle Database JDBC Developer's Guide and Referencefor more information on result sets and their features

4.1.3.1 Features of ResultSet Objects

Scrollability refers to the ability to move backward as well as forward through a result set. You can also move to any particular position in the result set, through either relative positioning or absolute positioning. Relative positioning lets you move a specified number of rows forward or backward from the current row. Absolute positioning lets you move to a specified row number, counting from either the beginning or the end of the result set.

When creating a scrollable or positionable result set, you must also specify sensitivity. This refers to the ability of a result set to detect and reveal changes made to the underlying database from outside the result set. A sensitive result set can see changes made to the database while the result set is open, providing a dynamic view of the underlying data. Changes made to the underlying column values of rows in the result set are visible. Updatability refers to the ability to update data in a result set and then copy the changes to the database. This includes inserting new rows into the result set or deleting existing rows. A result set may be updatable or read-only.

4.1.3.2 Summary of Result Set Object Types

Scrollability and sensitivity are independent of updatability, and the three result set types and two concurrency types combine for the following six result set categories:

Forward-only/read-only

Forward-only/updatable

Scroll-sensitive/read-only

Scroll-sensitive/updatable

Scroll-insensitive/read-only

Scroll-insensitive/updatable

Example 4-2 demonstrates how to declare a scroll-sensitive and read-only ResultSet object.

Example 4-2 Declaring a Scroll-Sensitive, Read-Only ResultSet Object

stmt = conn.createStatement(ResultSet.TYPE_SCROLL_SENSITIVE, ResultSet.CONCUR_READ_ONLY);

Note:

A forward-only updatable result set has no provision for positioning at a particular row within the ResultSet object. You can update rows only as you iterate through them using the next method.

4.2 Querying Data from a Java Application

This section discusses how you can use JDeveloper to create a Java class that queries data in Oracle Database in the following sections:

Creating a Method in JDeveloper to Query Data

Testing the Connection and the Query Methods

4.2.1 Creating a Method in JDeveloper to Query Data

The following steps show you how to add a simple query method to your DataHandler.java class. If DataHandler.java is not open in the JDeveloper integrated development environment (IDE), double-click it in the Application Navigator to display it in the Java Source Editor.

In the DataHandler class, add the following import statements after the existing import statements to use the Statement and ResultSet JDBC classes:

import java.sql.Statement;
import java.sql.ResultSet;

After the connection declaration, declare variables for Statement, ResultSet, and String objects as follows:

Statement stmt;
ResultSet rset;
String query;
String sqlString;

Create a method called getAllEmployees, which will be used to retrieve employee information from the database. Enter the signature for the method:

public ResultSet getAllEmployees() throws SQLException{

Press Enter to include a closing brace for this method, and a new line in which to start entering the method code.

Call the getDBConnection method created earlier:

getDBConnection();

Use the createStatement method of the Connection instance to provide context for executing the SQL statement and define the ResultSet type. Specify a read-only, scroll-sensitive ResultSet type:

stmt = conn.createStatement(ResultSet.TYPE_SCROLL_SENSITIVE, ResultSet.CONCUR_READ_ONLY);

The Java Code Insight feature can help you ensure that the statement syntax is correct.

Define the query and print a trace message. The following code uses a simple query: it returns all the rows and columns in the Employees table and the data is ordered by the Employee ID:

query = "SELECT * FROM Employees ORDER BY employee_id";
System.out.println("\nExecuting query: " + query);

Run the query and retrieve the results in the ResultSet instance as follows:

rset = stmt.executeQuery(query);

Return the ResultSet object:

return rset;

Save your work. From the File menu, select Save All.

The code for the getAllEmployees method should be as shown in Example 4-3.

Example 4-3 Using the Connection, Statement, Query, and ResultSet Objects

    public ResultSet getAllEmployees() throws SQLException{
        getDBConnection();
        stmt = conn.createStatement(ResultSet.TYPE_SCROLL_SENSITIVE,
               ResultSet.CONCUR_READ_ONLY);
        query = "SELECT * FROM Employees ORDER BY employee_id";
        System.out.println("\nExecuting query: " + query);
        rset = stmt.executeQuery(query);
        return rset;
    }

4.2.2 Testing the Connection and the Query Methods

In the following steps, you create a simple Java class to test the methods in the DataHandler.java class. To test your application at this stage, you can temporarily set the value of the jdbcUrl variable to the connection string for your database and set the values of the userid and password variables to the values required to access the HR schema ("hr" in each case).

Open the DataHandler.java class in the Java Visual Editor from the Application Navigator.

Change the jdbcUrl, userid and password variables to contain the values required for the HR schema as follows:

String jdbcUrl = "connect-string"
String userid = "hr";
String password = "hr";

where connect-string is, for example:

jdbc:oracle:thin:@dbhost.companyname.com:1521:ORCL

See Also:

Declaring Connection-Related Variables in Chapter 3

Create a new Java class in the hr package. Name it JavaClient, make it a public class, and generate a default constructor and a main method. The skeleton JavaClient.java class is created and displayed in the Java Source Editor.

See Also:

Chapter 3 for information on creating a Java class file

Import the ResultSet package:

import java.sql.ResultSet;

In the main method declaration, add exception handling as follows:

public static void main(String[] args) throws Exception{

Replace the JavaClient object created by default with a DataHandler object. Locate the following line:

JavaClient javaClient = new JavaClient();

Replace this with:

DataHandler datahandler = new DataHandler();

Define a ResultSet object to hold the results of the getAllEmployees query, and iterate through the rows of the result set, displaying the first four columns, Employee Id, First Name, Last Name, and Email. To do this, add the following code to the main method:

ResultSet rset = datahandler.getAllEmployees();

while (rset.next()) {
System.out.println(rset.getInt(1) + " " +
  rset.getString(2) + " " +
  rset.getString(3) + " " +
  rset.getString(4));
}

Compile the JavaClient.java file to check for compilation errors. To do this, right-click in the Java Source Editor, and select Make from the shortcut menu.

If there are no errors in compilation, you should see the following message in the Log window:

Successful compilation: 0 errors, 0 warnings

Run the JavaClient.java file. To do this, right-click in the Java Source Editor window and select Run from the shortcut menu.

Examine the output in the Log window. Notice the trace message, followed by the four columns from the Employees table as shown in Figure 4-1.

Figure 4-1 Test Output for Query Method in Log Window

Description of Figure 4-1 follows
Description of "Figure 4-1 Test Output for Query Method in Log Window"

When you finish testing the application, set the jdbcUrl, userid and password variables in DataHandler.java back to null.

See Also:

Declaring Connection-Related Variables

4.3 Creating JSP Pages

The HRApp application uses JavaServer Pages (JSP) technology to display data. JSP technology provides a simple, fast way to create server-independent and platform-independent dynamic Web content. A JSP page has the .jsp extension. This extension notifies the Web server that the page should be processed by a JSP container. The JSP container interprets the JSP tags and scriptlets, generates the content required, and sends the results back to the client as an HTML or XML page.

To develop JSP pages, you use some or all of the following:

HTML tags to design and format the dynamically generated Web page

Standard JSP tags or Java-based scriptlets to call other components that generate the dynamic content on the page

JSP tags from custom tag libraries that generate the dynamic content on the page

See Also:

Sun Microsystems documentation for JSP at

http://java.sun.com/products/jsp/

In this section, you will see how you can create JSP pages for the application in this guide in the following sections:

Overview of Page Presentation

Creating a Simple JSP Page

Adding Static Content to a JSP Page

Adding a Style Sheet to a JSP Page

4.3.1 Overview of Page Presentation

In the application created in this guide, JSP pages are used to do the following tasks:

Display data.

Hold input data entered by users adding employees and editing employee data.

Hold the code needed to process the actions of validating user credentials and adding, updating, and deleting employee records in the database.

Because JSP pages are presented to users as HTML or XML, you can control the presentation of data in the same way as you would for static HTML and XML pages. You can use standard HTML tags to format your page, including the title tag in the header to specify the title to be displayed for the page.

You use HTML tags for headings, tables, lists and other items on your pages. Style sheets can also be used to define the presentation of items. If you use JDeveloper to develop your application, you can select styles from a list.

The following sections describe the main elements used in the JSP pages of the sample application:

JSP Tags

Scriptlets

HTML Tags

HTML Forms

4.3.1.1 JSP Tags

JSP tags are used in the sample application in this guide for the following tasks: to initialize Java classes that hold the application methods and the JavaBean used to hold a single employee record, and to forward the user to either the same or another page in the application.

The jsp:useBean tag is used in pages to initialize the class that contains all the methods needed by the application, and the jsp:forward tag is used to forward the user to a specified page. You can drag the tags you need from the Component Palette of JSP tags, and enter the properties for the tag in the corresponding dialog box that is displayed.

See Also:

http://java.sun.com/products/javabeans/ for more information on JavaBeans

4.3.1.2 Scriptlets

Scriptlets are used to run the Java methods that operate on the database and to perform other processing in JSP pages. You can drag a scriptlet tag component from the Component Palette and drop it onto your page, ready to enter the scriptlet code. In JDeveloper, the code for scriptlets is entered in the Scriptlet Source Editor dialog box.

In this application, you use scriplets for a variety of tasks. As an example, one scriptlet calls the DataHandler method that returns a ResultSet object containing all the employees in the Employees table, which you can use to display that data in your JSP page. As another example, a scriplet is used to iterate through the same ResultSet object to display each item in a row of a table.

4.3.1.3 HTML Tags

HTML tags are typically used for layout and presentation of the nondynamic portions of the user interface, for example headings and tables. In JDeveloper, you can drag and drop a Table component from the Component Palette onto your page. You must specify the number of rows and columns for the table, and all the table tags are automatically created.

4.3.1.4 HTML Forms

HTML forms are used to interact with or gather information from the users on Web pages. The FORM element acts as a container for the controls on a page, and specifies the method to be used to process the form input.

For the filter control to select which employees to display, the employees.jsp page itself processes the form. For login, insert, edit, and delete operations, additional JSP pages are created to process these forms. To understand how the JSP pages in this application are interrelated, refer to Figure 1-2.

You can add a form in a JSP page by selecting it from the Component Palette of HTML tags. If you attempt to add a control on a page outside of the form component or in a page that does not contain a form, then JDeveloper prompts you to add a form component to contain it.

4.3.2 Creating a Simple JSP Page

The following steps describe how to create a simple JSP page:

In the Application Navigator, right-click the View project and choose New from the shortcut menu.

In the New Gallery, select the All Technologies tab.

Expand the Web Tier node from the Categories list and select JSP.

In the Items list, select JSP and click OK. The Create JSP Dialog box is displayed.

On the JSP File screen, enter a name for the JSP page and select JSP Page.

On the Create JSP screen, enter a name for the JSP page and click OK. The new page opens in the JSP/HTML Visual Editor and is ready for you to start adding text and components to your web page.

4.3.3 Adding Static Content to a JSP Page

JDeveloper provides the Component Palette and the Property Inspector on the right hand side of the JSP/HTML Visual Editor. You can also use the JSP Source Editor by clicking the Source Editor tab next to the Design tab at the bottom of the page. The Component Palette allows you to add components to the page and the Property Inspector allows you to set the properties of the components. A blank page in the Visual Editor is shown in Figure 4-2.

Figure 4-2 Adding Content to JSP Pages in the JDeveloper Visual Source Editor

Description of Figure 4-2 follows
Description of "Figure 4-2 Adding Content to JSP Pages in the JDeveloper Visual Source Editor"

The following steps show how you can add text to the employees.jsp page. They use the Visual Editor to modify the JSP. The Visual Editor is like a WYSIWYG editor and you can use it to modify content.

With employees.jsp open in the Visual Editor, in the top line of your page, enter AnyCo Corporation: HR Application. From the list of styles at the top of the page, on the left-hand side, select Heading 2.

With the cursor still on the heading you added, from the Design menu select Align, and then Center.

In a similar way, on a new line, enter Employee Data, and format it with the Heading 3 style. Position it on the left-hand side of the page.

4.3.4 Adding a Style Sheet to a JSP Page

You can add a style sheet reference to your page, so that your headings, text, and other elements are formatted in a consistent way with the presentation features, such as the fonts and colors used in the Web pages. You can add a style sheet to the page as follows:

With employees.jsp open in the Visual Editor, click the list arrow at the top right of the Component Palette, and select CSS.

From the CSS list, drag JDeveloper onto your page. As soon as you select the style sheet it is added to your page and formats the page with the JDeveloper styles. Figure 4-3 shows the JSP Page with the content added to it in the previous section and the JDeveloper stylesheet applied to it.

Figure 4-3 Adding Static Content to the JSP Page

Description of Figure 4-3 follows
Description of "Figure 4-3 Adding Static Content to the JSP Page"

Note:

In JDeveloper version 10.1.3, you can associate a stylesheet with the JSP page while creating it in the JSP Creation Wizard. The only difference is that you need to browse and locate the stylesheet to be applied to the JSP page, instead of just dragging and dropping it onto the page.

4.4 Adding Dynamic Content to the JSP Page: Database Query Results

This section includes the following subsections:

Adding a JSP useBean Tag to Initialize the DataHandler Class

Creating a Result Set

Adding a Table to the JSP Page to Display the Result Set

4.4.1 Adding a JSP useBean Tag to Initialize the DataHandler Class

A jsp:useBean tag identifies and initializes the class that holds the methods that run in the page. To add a jsp:useBean tag, follow these steps:

Open employees.jsp in the Visual Editor.

In the Component Palette, select the JSP set of components. Scroll through the list to select UseBean. Then, drag and drop it onto your JSP page, below the headings.

In the Insert UseBean dialog box, enter empsbean as the ID, and for the Class, browse and select the hr.DataHandler class. Set the Scope to session, and leave the Type and BeanName fields blank.

Click OK to create the tag in the page.

Figure 4-4 shows the representation of the useBean tag in the employees.jsp page.

Figure 4-4 useBean Representation in the employees.jsp File

Description of Figure 4-4 follows
Description of "Figure 4-4 useBean Representation in the employees.jsp File"

4.4.2 Creating a Result Set

The following steps describe how you can add a scripting element to your page to call the getAllEmployees method and hold the result set data that is returned. This query is defined in the DataHandler class, and initialized in the page by using the jsp:useBean tag.

Open the employees.jsp page in the Visual Editor. In the JSP part of the Component Palette, select Scriptlet and drag and drop it onto the JSP page next to the representation of the UseBean.

In the Insert Scriptlet dialog box, enter the following lines of code, which will call the getAllEmployees method and produce a ResultSet object:

ResultSet rset;
rset = empsbean.getAllEmployees();

Click OK. A representation of the scriptlet is displayed on the page as shown in Figure 4-5.

Figure 4-5 Scriptlet Representation in a JSP Page

Description of Figure 4-5 follows
Description of "Figure 4-5 Scriptlet Representation in a JSP Page"

Select the Source tab at the bottom of the Visual Editor to see the code that has been created for the page so far. A wavy line under ResultSet indicates that there are errors in the code.

The Structure window on the left-hand side also indicates any errors in the page. Scroll to the top of the window and expand the JSP Errors node. Figure 4-6 shows how the error in the code is shown in the Structure window.

Figure 4-6 Viewing Errors in the Structure Window

Description of Figure 4-6 follows
Description of "Figure 4-6 Viewing Errors in the Structure Window"

You must import the ResultSet package. To do this, click the page node in the Structure window to display the page properties in the Property Inspector.

Click in the empty box to the right of the import property. Click the ellipsis symbol (...). The import dialog box is displayed, which is shown in Figure 4-7.

Figure 4-7 Importing Packages in JDeveloper

Description of Figure 4-7 follows
Description of "Figure 4-7 Importing Packages in JDeveloper"

In the import list, select the Hierarchy tab, expand the java node, then the sql node, and then select ResultSet. Click OK.

On the Source tab, examine the code to see if the import statement has been added to the code for your page. The error should disappear from the list in the Structure window. Before continuing with the following sections, return to the design view of the page by selecting the Design tab.

4.4.3 Adding a Table to the JSP Page to Display the Result Set

The following steps describe how you can add a table to the JSP page to display the results of the getAllEmployees query:

If the employees.jsp page is not open in the Visual Editor, double-click it in the Application Navigator to open it, and work in the Design tab. With the employees.jsp file open in the Visual Editor, position the cursor after the scriptlet and from the HTML Common page of the Component Palette, select the Table component.

In the Insert Table dialog box, specify 1 row and 6 columns. Leave all Layout properties as defaults. Click OK.

In the table row displayed on the page, enter text as follows for the headings for each of the columns: First Name, Last Name, Email, Job, Phone, Salary. Use Heading 4 to format the column names.

Add a scripting element for output, this time to display the values returned for each of the columns in the table. To do this, select the table as follows. Position the cursor on the top border of the table, and click when the cursor image changes to a table image. From the JSP Component Palette, select Scriptlet. (You need not drag the scriptlet into your table; it is inserted automatically.)

In the Insert Scriptlet dialog box, enter the following lines of code:

    while (rset.next ())
    {
    out.println("<tr>");
    out.println("<td>" +
      rset.getString("first_name") + "</td><td> " +
      rset.getString("last_name") + "</td><td> " +
      rset.getString("email") + "</td><td> " +
      rset.getString("job_id") + "</td><td>" +
      rset.getString("phone_number") + "</td><td>" +
      rset.getDouble("salary") + "</td>");
    out.println("</tr>");
    }

Click OK.

The JSP page created is shown in Figure 4-8.

Figure 4-8 Table in a JSP Page

Description of Figure 4-8 follows
Description of "Figure 4-8 Table in a JSP Page"

4.5 Filtering a Query Result Set

You can filter the results of a query by certain parameters or conditions. You can also allow users of the application to customize the data filter. In the sample application created in this guide, the procedure of filtering the query result consists of the following tasks:

Determining what filtered set is required

Users can specify the set of employee records that they want to view by entering a filter criterion in a query field, in this case, a part of the name that they want to search for. The employees.jsp page accepts this input through form controls, and processes it.

Creating a method to return a query ResultSet

The user input string is used to create the SQL query statement. This statement selects all employees whose names include the sequence of characters that the user enters. The query searches for this string in both the first and the last names.

Displaying the results of the query

This is done by adding code to the employees.jsp page to use the method that runs the filtered query.

This section describes filtering query data in the following sections:

Creating a Java Method for Filtering Results

Testing the Query Filter Method

Adding Filter Controls to the JSP Page

Displaying Filtered Data in the JSP Page

4.5.1 Creating a Java Method for Filtering Results

The following steps describe how you can create the getEmployeesByName method. This method allows users to filter employees by their first or last name.

From the Application Navigator, open the DataHandler.java class in the Java Visual Editor.

After the getAllEmployees method, declare the getEmployeesByName method as follows:

public ResultSet getEmployeesByName(String name) throws SQLException {

}

Within the body of the method, add the following code to convert the name to uppercase to enable more search hits:

name = name.toUpperCase();

Call the method to connect to the database:

getDBConnection();

Specify the ResultSet type and create the query:

stmt = conn.createStatement(ResultSet.TYPE_SCROLL_SENSITIVE,
                            ResultSet.CONCUR_READ_ONLY);
query =
"SELECT * FROM Employees WHERE UPPER(first_name) LIKE \'%" + name + "%\'" +
" OR UPPER(last_name) LIKE \'%" + name + "%\' ORDER BY employee_id";

Print a trace message:

System.out.println("\nExecuting query: " + query);

Run the query and return a result set as before:

rset = stmt.executeQuery(query);
return rset;

Save the file and compile it to ensure there are no compilation errors.

4.5.2 Testing the Query Filter Method

You can use the JavaClient.java class created in Testing the Connection and the Query Methods to test the getEmployeesByName method. You must add the getEmployeesByName method to display the query results as described in the following steps:

Open the JavaClient.java class in the Java Source Editor.

After the result set displaying the results from the getAllEmployees query, define a result set for the conditional query as follows:

rset = datahandler.getEmployeesByName("King");

System.out.println("\nResults from query: ");

while (rset.next()) {
  System.out.println(rset.getInt(1) + " " +
  rset.getString(2) + " " +
  rset.getString(3) + " " +
  rset.getString(4));
}

To test your application at this stage, you can temporarily adjust the values of the jdbcUrl, userid and password variables in the DataHandler class to provide the values required for the HR schema. Save the file, and compile it to check for syntax errors.

Note:

Make sure you change the values of userid, password, and jdbcUrl back to null after testing. For more information, refer to Declaring Connection-Related Variables.

To test-run the code, right-click in the Java Source Editor and select Run from the shortcut menu. In the Log window, you will first see the results of the getAllEmployees method, then the results from the getEmployeesByName("xxx") query. Here, xxx is set to "King" to test the filtering functionality. In actual operation, this parameter will be set to the value provided by the user of the application to filter the search.

4.5.3 Adding Filter Controls to the JSP Page

To accept the filter criterion and to display the filter results, you must modify the employees.jsp page. In the following steps, you add a form element and controls to the employees.jsp page that accepts input from users to filter employees by name:

With the employees.jsp page displayed in the Visual Editor, position the cursor between the useBean tag and the scriptlet.

In the HTML Forms page of the Component Palette, select Form.

In the Insert Form dialog box, use the down arrow for the Action field and select employees.jsp. Leave the other fields empty and click OK.

The form is displayed on the page in the Visual Editor, represented by a dotted-line rectangle.

In the HTML Forms page of the Component Palette, scroll to Text Field. Select it and drag and drop it inside the Form component. In the Insert Text Field dialog, enter query as the value of the Name field and click OK. The text field box is displayed within the form. This field allows users to enter filter criteria.

Position the cursor to the left of the Text Field and add the following text:

Filter by Employee name:

In the HTML Forms page of the Component Palette, scroll to Submit Button. Select it and drop it inside the Form component to the right of the Text Field.

In the Insert Submit Button dialog box, leave the Name field empty and enter Filter as the value of the Value field, and click OK.

Figure 4-9 shows these HTML Form components in the employees.jsp file.

Figure 4-9 HTML Form Components in the JSP Page

Description of Figure 4-9 follows
Description of "Figure 4-9 HTML Form Components in the JSP Page"

4.5.4 Displaying Filtered Data in the JSP Page

In the previous section, you created a text field component on the JSP page that accepts user inputs. In this text field, users can specify a string with which to filter employee names. You also added a submit button.

In the following steps, you add code to the scriptlet in the employees.java file to enable it to use the getEmployeesByName method. This method is used only if a user submits a value for filtering the results. If this filter criterion is not specified, the getAllEmployees method is used.

Open the employees.jsp file in the Visual Editor.

Double-click the Scriptlet tag on the page (not the one inside the table) to open the Properties dialog box. Modify the code as follows:

ResultSet rset;
String query = request.getParameter("query");
if (query != null && query != null)
  rset = empsbean.getEmployeesByName(query);
else
  rset = empsbean.getAllEmployees();

Figure 4-10 shows how you can use the Scriptlet Properties dialog box to modify the code.

Figure 4-10 Using the Scriptlet Properties Dialog Box

Description of Figure 4-10 follows
Description of "Figure 4-10 Using the Scriptlet Properties Dialog Box"

Click OK.

Save the file.

4.6 Adding Login Functionality to the Application

The login functionality used in the sample application is a simple example of application-managed security. It is not a full Java EE security implementation, but simply used as an example in the sample application.

To implement this simple login functionality, you must perform the following tasks:

Creating a Method to Authenticate Users

Creating a Login Page

Preparing Error Reports for Failed Logins

Creating the Login Interface

Creating a JSP Page to Handle Login Action

4.6.1 Creating a Method to Authenticate Users

In the following steps, you create a method in the DataHandler.java class that authenticates users by checking that the values they supply for the userid and password match those required by the database schema.

Open the DataHandler.java class in the Source Editor.

Create a method called authenticateUser that checks if the userid, password, and host values supplied by a user are valid:

public boolean authenticateUser(String jdbcUrl, String userid, String password,
  HttpSession session) throws SQLException {

}

JDeveloper prompts you with a wavy underline and a message that you need to import a class for HttpSession. Press the Alt+Enter keys to import the javax.servlet.http.HttpSession class.

Within the body of the method, assign the jdbcUrl, userid, and password values from the call to the attributes of the current object as follows:

this.jdbcUrl= jdbcUrl;
this.userid = userid;
this.password = password;

Attempt to connect to the database using the values supplied, and if successful, return a value of true. Enclose this in a try block as follows:

try {
  OracleDataSource ds;
  ds = new OracleDataSource();
  ds.setURL(jdbcUrl);
  conn = ds.getConnection(userid, password);
  return true;
}

See Also:

For information about using try and catch blocks, refer to Exception Handling in Chapter 5.

To handle the case where the login credentials do not match, after the try block, add a catch block. The code in this block prints out a log message and sets up an error message. This error message can be displayed to the user if a login attempt fails. The jdbcUrl, userid and password variables are set back to null, and the method returns the value false. To do this, enter the following code:

catch ( SQLException ex )  {
  System.out.println("Invalid user credentials");
  session.setAttribute("loginerrormsg", "Invalid Login. Try Again...");
  this.jdbcUrl = null;
  this.userid = null;
  this.password = null;
  return false;
}

The complete code is shown in Example 4-4.

Example 4-4 Implementing User Validation

public boolean authenticateUser(String jdbcUrl, String userid, String password,
  HttpSession session) throws SQLException {

  this.jdbcUrl = jdbcUrl;
  this.userid = userid;
  this.password = password;
  try {
    OracleDataSource ds;
    ds = new OracleDataSource();
    ds.setURL(jdbcUrl);
    conn = ds.getConnection(userid, password);
    return true;
  } catch ( SQLException ex )  {
  System.out.println("Invalid user credentials");
  session.setAttribute("loginerrormsg", "Invalid Login. Try Again...");
  this.jdbcUrl = null;
  this.userid = null;
  this.password = null;
  return false;
  }
}

4.6.2 Creating a Login Page

The following steps create a login.jsp page, on which users enter the login details for the schema they are going to work on:

In the View project, create a new JSP page. Change the Name to login.jsp and accept all other defaults. The new page opens in the JSP/HTML Visual Editor and is ready for you to start adding text and components to your Web page.

Apply the JDeveloper style sheet to the page.

Give the page the same heading as earlier, AnyCo Corporation: HR Application, apply the Heading 2 style to it, and align it to the center of the page.

On the next line, enter Application Login, with the Heading 3 style applied. Align this heading to the left-hand side of the page.

4.6.3 Preparing Error Reports for Failed Logins

The following steps add functions to the login.jsp page for displaying error messages when a user login fails. The scriptlets and expression used in the login.jsp page set up a variable to hold any error message. If the user login fails, the connection method sets a message for the session. This page checks to see if there is such a message, and if present, it displays the message.

With the login.jsp page open in the Visual Editor, position the cursor after the text on this page. Then, from the JSP page of the Component Palette, drag and drop the Scriptlet element from the palette onto the page.

In the Insert Scriptlet dialog box, enter the following code:

    String loginerrormsg = null;
    loginerrormsg = (String) session.getAttribute("loginerrormsg");
    if (loginerrormsg != null) {

Add another scriptlet in exactly the same way, and this time enter only a single closing brace (}) in the Insert Scriptlet dialog box.

Place the cursor between the two scriptlets and press Enter to create a new line. Apply the Heading 4 style to the new line.

With the cursor still on the new line, in the JSP page of the Component Palette, click Expression.

In the Insert Expression dialog box, enter loginerrormsg.

To see the code that has been added to your login.jsp page, below the Visual Editor, select the Source tab. The code should appear as follows:

<%
    String loginerrormsg = null;
    loginerrormsg = (String) session.getAttribute("loginerrormsg");
    if (loginerrormsg != null) {
%>
<h4>
  <%=  loginerrormsg %>
</h4>
<%
}
%>

Before continuing with the following sections, return to the design view of the page by selecting the Design tab.

4.6.4 Creating the Login Interface

In these steps, you add fields to the login.jsp page on which users enter their login details.

If the login.jsp page is not open in the Visual Editor, double-click it in the Application Navigator to open it, and check that the Design tab is selected.

Position the cursor after the second scriptlet and, in the HTML Forms page of the Component Palette, select Form. The Form is displayed on the page in the Visual Editor, represented by a dotted-line rectangle.

In the HTML Forms page of the Component Palette, select Form. In the Insert Form dialog box, enter login_action.jsp as the value for the Action field. This file will be used to process the user input in the login.jsp file. (You cannot select this page from a list as it is not created yet.) Leave the other fields empty and click OK.

The Form is displayed on the page in the Visual Editor, represented by a dotted rectangle.

Add a Table to the page. Position it inside the Form. Specify a 3-row and 2-column layout, and accept other layout defaults.

In the first column of the three rows, enter the following as the text to display for users:

User ID:

Password:

Host:

From the HTML page of the Component Palette, drag a Text Field into the table cell to the right of the User ID: cell. In the Insert Text Field dialog box, enter userid as the value of the Name property. Leave the other fields empty and click OK.

In the same way, add a Text Field to the table cell to the right of the Password: cell and enter password as the value of the Name property. Similarly, add a Text Field to the table cell to the right of the Host: cell and enter host as the value of the Name property.

Drag a Submit button to the Form below the table. Enter Submit for the Value property of the button.

Your login.jsp page should now appear as shown in Figure 4-11.

Figure 4-11 Login Page

Description of Figure 4-11 follows
Description of "Figure 4-11 Login Page"

4.6.5 Creating a JSP Page to Handle Login Action

In the following steps, you create the login_action.jsp page, which is a nonviewable page that processes the login operation.

Create a JSP page and call it login_action.jsp. Accept all default settings for the JSP page.

With login_action.jsp open in the Visual Editor, from the JSP page of the Component Palette, drag a Page Directive component to the page. In the Insert Page Directive dialog box, for the Import field, browse to import java.sql.ResultSet. Click OK.

Drag a jsp:usebean tag onto the page. Enter empsbean as the ID and browse to select hr.DataHandler as the Class. Set the Scope to session, and click OK.

Position the cursor after the useBean tag and add a Scriptlet to the page. Enter the following code into the Insert Scriptlet dialog box and click OK.

boolean userIsValid = false;
String host = request.getParameter("host");
String userid = request.getParameter("userid");
String password = request.getParameter("password");
String jdbcUrl = "jdbc:oracle:thin:@" + host + ":1521:ORCL";
userIsValid = empsbean.authenticateUser(jdbcUrl, userid, password, session);

Add another Scriptlet, and add the following code to it:

if (userIsValid){

In the JSP page of the Component Palette, find Forward and drag it onto the page to add a jsp:forward tag onto the page. In the Insert Forward dialog box, enter employees.jsp.

Add another scriptlet, and enter the following code:

} else {

Add another jsp:forward tag, and this time move forward to login.jsp.

Add a final Scriptlet, and enter a closing brace (}).

Save your work.

To see the code that has been added to login_action.jsp, select the Source tab. The code displayed is similar to the following:

<body>
<%@ page import="java.sql.ResultSet"%><jsp:useBean id="empsbean"
                                                   class="hr.DataHandler"
                                                   scope="session"/>
<%boolean userIsValid = false;
String host = request.getParameter("host");
String userid = request.getParameter("userid");
String password = request.getParameter("password");
String jdbcUrl = "jdbc:oracle:thin:@" + host + ":1521:ORCL";
userIsValid = empsbean.authenticateUser(jdbcUrl, userid, password, session);%><%if (userIsValid){%><jsp:forward page="employees.jsp"/><%if (userIsValid){%><jsp:forward page="login.jsp"/><%}%>
</body>

4.7 Testing the JSP Page

To test the login page and the filtering of employees, do the following:

In the Application Navigator, right-click the view project, and select Run.

You might be prompted to specify a Default Run Target for the project. For now, set this to login.jsp. You can later change the project properties for the default run target page to be any page of your choice.

The login page is displayed in your browser, as shown in Figure 4-12.

Figure 4-12 Login Page for Sample Application in the Browser

Description of Figure 4-12 follows
Description of "Figure 4-12 Login Page for Sample Application in the Browser"

Enter the following login details for your database, and then click Submit.

User ID: hr

Password: hr

Host: Host name of the machine with Oracle Database

The Employee.java file is displayed in your browser as shown in Figure 4-13.

Figure 4-13 Unfiltered Employee Data in employee.jsp

Description of Figure 4-13 follows
Description of "Figure 4-13 Unfiltered Employee Data in employee.jsp"

Enter a string of letters by which you want to filter employee data. For example, enter ing in the Filter by Employee Name field, and click Filter. A filtered list is displayed, which is shown in:

Figure 4-14 Filtered Employee Data in employee.jsp

Description of Figure 4-14 follows
Description of "Figure 4-14 Filtered Employee Data in employee.jsp"

5 Updating Data

In this chapter, you will see how you can modify the sample application and add functionality that allows users to edit, update, and delete data in Oracle Database. This chapter includes the following sections:

Creating a JavaBean

Updating Data from a Java Class

Inserting an Employee Record

Deleting an Employee Record

Exception Handling

Navigation in the Sample Application

5.1 Creating a JavaBean

In outline, a bean is a Java class that has properties, events and methods. For each of its properties, the bean also includes accessors, that is get and set methods. Any object that conforms to certain basic rules can be a bean. There is no special class that has to be extended to create a bean.

In the steps for creating a sample application in this chapter, a JavaBean is used to hold a single employee record. When a user wants to edit an existing record or add a new one, it is used as a container to hold the changed or new values for a single row of a table to prepare the row for using to update the database.

The bean contains properties for each field in an employee record, and then JDeveloper creates the accessors (get and set methods) for each of those properties. You will see how to create a JavaBean for the sample application in the following subsections:

Creating a JavaBean in JDeveloper

Defining the JavaBean Properties and Methods

5.1.1 Creating a JavaBean in JDeveloper

Employee.java is the JavaBean that is used in the sample application to hold a single employee record and modify its contents. To create a JavaBean, do the following:

Right-click the View project, and from the shortcut menu, click New.

In the New Gallery dialog box, select the All Technologies tab.

Expand the General category and select JavaBeans in the General category. From the Items list, select Bean. Click OK.

In the Create Bean dialog box, enter Employee as the name, hr as the package, and ensure that the Extends: field is set to java.lang.Object. Click OK to create the bean.

Save the file. The Employee.java file should now contain the following code:

package hr;

public class Employee {
  public Employee(){
  }
}

5.1.2 Defining the JavaBean Properties and Methods

In the JavaBean, you must create one field for each column in the Employees table, and accessor methods (get and set methods) for each field.

Add an import statement for java.sql.Date, which is the field type for one of the fields:

import java.sql.Date;

Add a field to the Employee class for each of the columns in the Employees table. Each field is private, and the field types are as follows:

  private Integer employeeId;
  private String firstName;
  private String lastName;
  private String email;
  private String phoneNumber;
  private Date hireDate;
  private String jobId;
  private Double salary;
  private Double commissionPct;
  private Integer departmentId;

Right-click on the Source Editor page and select Generate Accessors from the shortcut menu. In the Generate Accessors dialog box, select the top-level Employee node. A check mark is displayed for that node and for all the fields. Click OK. Figure 5-1 shows the Generate Accessors dialog box with all the fields selected.

Figure 5-1 Generate Accessors Dialog Box

Description of Figure 5-1 follows
Description of "Figure 5-1 Generate Accessors Dialog Box"

Save the file. The Employee.java file should now contain the following code:

Example 5-1 Skeleton Code for a Basic Java Bean with Accessor Methods

package hr;
import java.sql.Date;

public class Employee {
    public Employee() {
    }
    private Integer employeeId;
    private String firstName;
    private String lastName;
    private String email;
    private String phoneNumber;
    private Date hireDate;
    private String jobId;
    private Double salary;
    private Double commissionPct;
    private Integer departmentId;

    public void setEmployeeId(Integer employeeId) {
        this.employeeId = employeeId;
    }

    public Integer getEmployeeId() {
        return employeeId;
    }

    public void setFirstName(String firstName) {
        this.firstName = firstName;
    }

    public String getFirstName() {
        return firstName;
    }
...
...
...
...
// This list has been shortened and is not comprehensive. The actual code contains // accessor methods for all the fields declared in the bean.

    public void setDepartmentId(Integer departmentId) {
        this.departmentId = departmentId;
    }

    public Integer getDepartmentId() {
        return departmentId;
    }
}

5.2 Updating Data from a Java Class

Updating a row in a database table from a Java application requires you to do the following tasks:

Create a method that finds a particular employee row. This is used to display the values for a particular employee on an edit page.

Create a method that takes the updated employee data from the bean and updates the database.

On the main application page, in every row of employee data, include a link that allows a user to edit the data for that employee. The links take the user to the edit.jsp file with the data for that employee displayed, ready for editing.

Create a JSP page called edit.jsp, that includes a form and a table to display all the data of a single employee and allows a user to change the values.

Create a JSP page that processes the form on the edit.jsp page, writes the updated values to the Employee.java bean and calls the updateEmployee method.

You will see how to do this in the following sections:

Creating a Method to Identify an Employee Record

Creating a Method to Update Employee Data

Adding a Link to Navigate to an Update Page

Creating a JSP Page to Edit Employee Data

Creating a JSP Page to Handle an Update Action

5.2.1 Creating a Method to Identify an Employee Record

The method you create in these steps is used to find the record for a particular employee. It is used when a user wants to edit or delete a particular employee record, and selects a link for that employee on the Employee.java page.

If the DataHandler class is not already open in the Java Source Editor, double-click it in the Application Navigator to open it.

In the DataHandler class, declare a new method that identifies the employee record to be updated:

public Employee findEmployeeById(int id) throws SQLException {

}

Within the body of this method, create a new instance of the Employee bean called selectedEmp.

Employee selectedEmp = new Employee();

Connect to the database.

getDBConnection();

Create a Statement object, define a ResultSet type, and formulate the query. Add a trace message to assist with debugging.

stmt =
  conn.createStatement(ResultSet.TYPE_SCROLL_SENSITIVE,
                       ResultSet.CONCUR_READ_ONLY);
query = "SELECT * FROM Employees WHERE employee_id = " + id;
System.out.println("\nExecuting: " + query);

Run the query and use a ResultSet object to contain the result.

rset = stmt.executeQuery(query);

Use the result set returned in rset to populate the fields of the employee bean using the set methods of the bean.

while (rset.next()) {
  selectedEmp.setEmployeeId(new Integer(rset.getInt("employee_id")));
  selectedEmp.setFirstName(rset.getString("first_name"));
  selectedEmp.setLastName(rset.getString("last_name"));
  selectedEmp.setEmail(rset.getString("email"));
  selectedEmp.setPhoneNumber(rset.getString("phone_number"));
  selectedEmp.setHireDate(rset.getDate("hire_date"));
  selectedEmp.setSalary(new Double(rset.getDouble("salary")));
  selectedEmp.setJobId(rset.getString("job_id"));
}

Return the populated object.

return selectedEmp;

5.2.2 Creating a Method to Update Employee Data

In the following steps, you will see how to create a method to update employee data in the database:

Open the DataHandler class.

Declare an updateEmployee method as follows:

public String updateEmployee(int employee_id, String first_name,
                             String last_name, String email,
                             String phone_number, String salary,
                             String job_id) throws SQLException {

}

Within the body of this method, create an instance of the Employee bean, containing details for the selected employee:

Employee oldEmployee = findEmployeeById(employee_id);

Connect to the database.

getDBConnection();

Create a Statement object and specify the ResultSet type as before.

stmt =
  conn.createStatement(ResultSet.TYPE_SCROLL_SENSITIVE,
                       ResultSet.CONCUR_READ_ONLY);

Create a StringBuffer to accumulate details of the SQL UPDATE statement that needs to be built:

StringBuffer columns = new StringBuffer( 255 );

For each field in an employee record, check whether the user has changed the value and if so, add relevant code to the StringBuffer. For each item added after the first one, add a comma to separate the items. The following code checks if the first_name variable changed, and if so, adds details to the SQL in the StringBuffer that will be used to update the database:

  if ( first_name != null &&
     !first_name.equals(oldEmployee.getFirstName() ) )
  {
    columns.append( "first_name = '" + first_name + "'" );
  }

For the last_name, before appending the new last name, check to see whether there are already some changes in the StringBuffer and if so, append a comma to separate the new change from the previous one. Use the following code:

  if ( last_name != null &&
      !last_name.equals(oldEmployee.getLastName() ) ) {
    if ( columns.length() > 0 ) {
      columns.append( ", " );
    }
    columns.append( "last_name = '" + last_name + "'" );
  }

Use the samecode logic to check for changes made to email, and phone_number.

Note:

Only significant parts of the code are included within this procedure. Example 5-2 contains the complete code for this method.

For the salary field, obtain a String value to add to the StringBuffer as follows:

  if ( salary != null &&
      !salary.equals( oldEmployee.getSalary().toString() ) ) {
    if ( columns.length() > 0 ) {
      columns.append( ", " );
    }
    columns.append( "salary = '" + salary + "'" );

When the whole set of changes has been assembled, check to see whether there are in fact any changes, that is, whether the StringBuffer contains anything. If so, construct a SQL UPDATE statement using the information in the StringBuffer and execute it. If the StringBuffer does not contain any changes, output a message saying so:

  if ( columns.length() > 0 )
  {
    sqlString = "update Employees SET " + columns.toString() +
            " WHERE employee_id = " + employee_id;
    System.out.println("\nExecuting: " + sqlString);
    stmt.execute(sqlString);
  }
  else
  {
    System.out.println( "Nothing to do to update Employee Id: " +
                        employee_id);
  }

Return the word "success".

return "success";

Save your work and make the file to check there are no syntax errors.

Example 5-2 contains the complete code for this method.

Example 5-2 Method for Updating a Database Record

public String updateEmployee(int employee_id, String first_name,
                             String last_name, String email,
                             String phone_number, String salary,
                             String job_id) throws SQLException {

  Employee oldEmployee = findEmployeeById(employee_id);
  getDBConnection();
  stmt = conn.createStatement(ResultSet.TYPE_SCROLL_SENSITIVE,
                              ResultSet.CONCUR_READ_ONLY);

  StringBuffer columns = new StringBuffer( 255 );
  if ( first_name != null &&
     !first_name.equals( oldEmployee.getFirstName() ) )
  {
    columns.append( "first_name = '" + first_name + "'" );
  }
  if ( last_name != null &&
      !last_name.equals( oldEmployee.getLastName() ) ) {
    if ( columns.length() > 0 ) {
      columns.append( ", " );
    }
    columns.append( "last_name = '" + last_name + "'" );
  }
  if ( email != null &&
      !email.equals( oldEmployee.getEmail() ) ) {
    if ( columns.length() > 0 ) {
      columns.append( ", " );
    }
    columns.append( "email = '" + email + "'" );
  }
  if ( phone_number != null &&
      !phone_number.equals( oldEmployee.getPhoneNumber() ) ) {
    if ( columns.length() > 0 ) {
      columns.append( ", " );
    }
    columns.append( "phone_number = '" + phone_number + "'" );
  }
  if ( salary != null &&
      !salary.equals( oldEmployee.getSalary().toString() ) ) {
    if ( columns.length() > 0 ) {
      columns.append( ", " );
    }
    columns.append( "salary = '" + salary + "'" );
  }
  if ( job_id != null &&
      !job_id.equals( oldEmployee.getJobId() ) ) {
    if ( columns.length() > 0 ) {
      columns.append( ", " );
    }
    columns.append( "job_id = '" + job_id + "'" );
  }

  if ( columns.length() > 0 )
  {
  sqlString =
    "UPDATE Employees SET " + columns.toString() +
      " WHERE employee_id = " + employee_id;
    System.out.println("\nExecuting: " + sqlString);
    stmt.execute(sqlString);
  }
  else
  {
    System.out.println( "Nothing to do to update Employee Id: " +
                        employee_id);
  }
  return "success";
}

5.2.3 Adding a Link to Navigate to an Update Page

In the following steps, you add a link to each row of the employees table on the employees.jsp page, that users will click to edit that row.

Open employees.jsp in the Visual Editor.

Add an extra column to the table that displays employee details. To do this, position the cursor in the last column of the table, right-click and select Table from the shortcut menu, then select Insert Rows Or Columns. In the Insert Rows or Columns dialog box, select Columns and After Selection and click OK.

This extra column will contain the link that reads Edit for each row. Each of these links leads to a separate page where the selected employee record can be edited. To do this, double-click the scriptlet that is inside the Employees table, to display the Scriptlet Properties dialog box.

Modify the scriptlet to include a link to the edit.jsp page. The modified scriptlet should contain the following code:

    while (rset.next ())
    {
    out.println("<tr>");
      out.println("<td>" +
      rset.getString("first_name") + "</td><td> " +
      rset.getString("last_name") + "</td><td> " +
      rset.getString("email") + "</td><td> " +
      rset.getString("job_id") + "</td><td>" +
      rset.getString("phone_number") + "</td><td>" +
      rset.getDouble("salary") +
      "</td><td> <a href=\"edit.jsp?empid=" + rset.getInt(1) +
      "\">Edit</a></td>");
    out.println("<tr>");
    }

When the edit link is clicked for any employee, this code passes the employee ID to the edit.jsp page, which will handle the employee record updates. The edit.jsp page will use this to search for the record of that particular employee in the database.

Save employees.jsp. Figure 5-2 shows employees.jsp when it is run and displayed in a browser, illustrating the link users can click to edit employee data.

Figure 5-2 Link to Edit Employees in employees.jsp

Description of Figure 5-2 follows
Description of "Figure 5-2 Link to Edit Employees in employees.jsp"

5.2.4 Creating a JSP Page to Edit Employee Data

In this section, you will create the edit.jsp file that allows users to update an employee record.

Create a new JSP page and name it edit.jsp. Accept all other defaults.

Give the page the same heading as earlier, AnyCo Corporation: HR Application, apply the Heading 2 style to it, and align it to the center of the page.

On the next line, type Edit Employee Record, with the Heading 3 style applied. Align this heading to the left of the page.

Add the JDeveloper style sheet to the page.

Add a jsp:usebean tag. Enter empsbean as the ID, and hr.DataHandler as the Class. Set the Scope to session, and click OK.

Position the cursor after the useBean tag and add another jsp:usebean tag. This time enter employee as the ID, browse to select hr.Employee as the class, and leave the Scope as page. Click OK.

Add a Scriptlet to the page. The scriptlet code passes the employee ID to the findEmployeeById method and retrieves the data inside the Employee bean. Enter the following code in the Insert Scriptlet dialog box:

Integer employee_id = new Integer(request.getParameter("empid"));
employee = empsbean.findEmployeeById(employee_id.intValue());

Add a Form to the page. In the Insert Form dialog, enter update_action.jsp for the Action field. You cannot select this page from the drop down list as you have not yet created it.

Add a Table to the page. Position it inside the Form. Specify a 6-row and 2-column layout, and accept other layout defaults.

In the first column, enter the following headings, each on a separate row: First Name, Last Name, Email, Phone, Job, Monthly Salary.

Drag a Hidden Field component from the HTML Forms page of the Component Palette. Drop it in the second column, adjacent to the First Name heading. In the Insert Hidden Field dialog, enter employee_id as the Name property and enter <%= employee.getEmployeeId() %> as the Value property.

Drag a Text Field component to this column, adjacent to the First Name heading. In the Insert Text Field dialog, enter first_name in the Name field, and <%= employee.getFirstName() %> in the Value field. Click OK.

Drag a second Text Field component to this column, adjacent to the Last Name heading. In the Insert Text Field dialog, enter last_name in the Name field, and <%= employee.getLastName() %> in the Value field. Click OK.

In a similar way, add text fields adjacent to each of the remaining column headings, using email, phone_number, job_id, and salary as the field names and the corresponding getter method for each field. These are specified in the following table.

Add a Submit button in the form, below the table. Enter Update as its Value.

Save the application.

The resultant edit.jsp page should look similar to the page shown in Figure 5-3.

Figure 5-3 Creating a JSP Page to Edit Employee Details

Description of Figure 5-3 follows
Description of "Figure 5-3 Creating a JSP Page to Edit Employee Details"

5.2.5 Creating a JSP Page to Handle an Update Action

In this section, you will see how to create the update_action.jsp file. This page processes the form on the edit.jsp page that allows users to update an employee record. There are no visual elements on this page, this page is used only to process the edit.jsp form and returns control to the employees.jsp file.

Create a new JSP page and call it update_action.jsp. Accept all other defaults for the page in the JSP Creation Wizard.

Drag a Page Directive component from the JSP page of the Component Palette onto the page. In the Insert Page Directive dialog box, browse to import java.sql.ResultSet. Click OK.

Add a jsp:usebean tag. Enter empsbean as the ID, and hr.DataHandler as the Class. Set the Scope to session, and click OK.

Add a Scriptlet to the page. Enter the following code into the Insert Scriptlet dialog box:

Integer employee_id = new Integer(request.getParameter("employee_id"));
String first_name = request.getParameter("first_name");
String last_name = request.getParameter("last_name");
String email = request.getParameter("email");
String phone_number = request.getParameter("phone_number");
String salary = request.getParameter("salary");
String job_id = request.getParameter("job_id");
empsbean.updateEmployee(employee_id.intValue(), first_name, last_name, email, phone_number, salary, job_id );

Drag a jsp:forward tag onto the page. In the Insert Forward dialog box, enter employees.jsp for the Page property.

Save your work.

Run the project and test whether you can edit an employee record. Click Edit for any employee on the employees.jsp page, and you should be directed to the page shown in Figure 5-4. Modify any of the employee details and check whether the change reflects in the employees.jsp page.

Figure 5-4 Editing Employee Data

Description of Figure 5-4 follows
Description of "Figure 5-4 Editing Employee Data"

5.3 Inserting an Employee Record

The steps for inserting a new employee record to the Employees table are similar to the process for updating an employee record:

Create a method to insert a new employee row into the Employees table.

Add a link to the main application page, allowing a user to click to insert a new employee. The link takes the user to an insert.jsp with an empty form ready for the user to enter details for the new row.

Create a JSP page to process the form on the insert.jsp page.

Create a JSP page with form controls for users to enter the values for the new employee.

This section covers the creation of Java application code for inserting new employee data in the following subsections:

Creating a Method to Insert Data

Adding a Link to Navigate to an Insert Page

Creating a JSP Page to Handle an Insert Action

Creating a JSP Page to Enter New Data

5.3.1 Creating a Method to Insert Data

In the following steps, you will create a method for inserting a new employee record.

Open DataHandler.java in the Java Source Editor.

Declare a method to add a new employee record.

public String addEmployee(String first_name,
  String last_name, String email,
  String phone_number, String job_id, int salary) throws SQLException {

}

Add a line to connect to the database.

getDBConnection();

Create a Statement object, define a ResultSet type as before, and formulate the SQL statement.

stmt =
  conn.createStatement(ResultSet.TYPE_SCROLL_SENSITIVE,
                       ResultSet.CONCUR_READ_ONLY);
sqlString =
  "INSERT INTO Employees VALUES (EMPLOYEES_SEQ.nextval, '" +
  first_name + "','" +
  last_name + "','" +
  email + "','" +
  phone_number + "'," +
  "SYSDATE, '" +
  job_id + "', " +
  salary + ",.30,100,80)";

Note:

The last three columns (Commission, ManagerId, and DepartmentId) contain hard-coded values for the sample application.

Add a trace message, and then run the SQL statement.

Return a message that says "success" if the insertion was successful.

Make the file to check for syntax errors.

Example 5-3 shows the code for the addEmployee() method.

Example 5-3 Method for Adding a New Employee Record

public String addEmployee(String first_name,
  String last_name, String email,
  String phone_number, String job_id, int salary) throws SQLException {
  getDBConnection();
  stmt = conn.createStatement(ResultSet.TYPE_SCROLL_SENSITIVE,
                              ResultSet.CONCUR_READ_ONLY);
  sqlString =
    "INSERT INTO Employees VALUES (EMPLOYEES_SEQ.nextval, '" +
     first_name + "','" +
    last_name + "','" +
    email + "','" +
    phone_number + "'," +
    "SYSDATE, '" +
    job_id + "', " +
    salary + ",.30,100,80)";

  System.out.println("\nInserting: " + sqlString);
  stmt.execute(sqlString);
  return "success";
}

5.3.2 Adding a Link to Navigate to an Insert Page

In these steps, you add a link to the header row of the employees table that users can click to add a new employee.

Open employees.jsp in the Visual Editor.

Drag a Hyper Link component from the HTML Common page of the Component Palette into the empty column header cell at the end of the header row. In the Insert HyperLink dialog box, enter insert.jsp in the HyperLink field, and Insert Employee in the Text field. You cannot browse to find insert.jsp as you have not yet created it. Click OK.

Save employees.jsp.

5.3.3 Creating a JSP Page to Enter New Data

In these steps, you create the insert.jsp page, which allows users to enter details of a new employee record.

Create a new JSP page and call it insert.jsp.

Give the page the same heading as before, AnyCo Corporation: HR Application, and format it as Heading 2, and center it.

On the next line enter Insert Employee Record, and apply the Heading 3 format. Align this heading to the left of the page.

Add the JDeveloper stylesheet to the page.

Add a Form. In the Insert Form dialog box, enter insert_action.jsp for the Action property, and click OK.

Add a Table inside the Form. Specify that you want 6 rows and 2 columns and accept all other layout defaults.

In the first column, enter the following headings, each on a separate row: First Name, Last Name, Email, Phone, Job, Monthly Salary.

Drag and drop a Text Field into the column to the right of the First Name header. In the Insert Field dialog box, type first_name in the Name property.

Drag a Text Field next to each of the Last Name, Email, Phone, and Monthly Salary headers. Specify the values for each of these text fields for the Name property in the Insert Field dialog box. The values are indicated in the following table:

Text Field For | Set the Name Property To
Last Name | last_name
Email | email
Phone | phone_number
Monthly Salary | salary

This procedure is different for the Job row.

Drag a Combo Box component from the HTML Forms page of the Component Palette to the column next to the Job heading.

In the Insert Select dialog box, enter job_id as the name, and 1 as the size. Click on the add (+) icon and enter SA_REP in the Value field, and in the Caption field, enter Sales Representative. Click on the add(+) sign to add each of the following job titles, then click OK.

Value | Caption
HR_REP | HR Representative
PR_REP | PR Representative
MK_MAN | Marketing Manager
SA_MAN | Sales Manager
FI_MAN | Finance Manager
IT_PROG | Software Developer
AD_VIP | Vice President

Drag a Submit button to the Form below the table. In the Insert Submit Button dialog box, enter Add Employee for the Value property.

Save your work.

Figure 5-5 shows the insert.jsp page in the Visual Editor.

Figure 5-5 Form to Insert Employee Data

Description of Figure 5-5 follows
Description of "Figure 5-5 Form to Insert Employee Data"

5.3.4 Creating a JSP Page to Handle an Insert Action

In these steps, you create the insert_action.jsp page. This is a page that processes the form input from insert.jsp, which is the page on which users enter a new employee record. There are no visual elements on this page, and it is only used to process the insert.jsp form and return control to the employees.jsp file.

Create a JSP page as before. Call it insert_action.jsp.

Add a jsp:usebean tag. As before, enter empsbean as the ID, and hr.DataHandler as the Class. Set the Scope to session, and click OK.

Position the cursor after the useBean tag and add a Scriptlet to the page. Enter the following code into the Insert Scriptlet dialog box:

String first_name = request.getParameter("first_name");
String last_name = request.getParameter("last_name");
String email = request.getParameter("email");
String phone_number = request.getParameter("phone_number");
String job_id = request.getParameter("job_id");
Integer salary = new Integer(request.getParameter("salary"));

empsbean.addEmployee(first_name, last_name, email, phone_number, job_id, salary.intValue());

Drag a jsp:forward tag onto the page. In the Insert Forward dialog box, enter employees.jsp.

Save your work.

Run the View project to test whether you can insert a new employee record.

To insert an employee, click Insert Employee on the employees.jsp page shown in Figure 5-6.

Figure 5-6 Inserting New Employee Data

Description of Figure 5-6 follows
Description of "Figure 5-6 Inserting New Employee Data"

Figure 5-7 shows the page where you can insert new employee data with some data filled in, and the list of jobs being used to select a job.

Figure 5-7 Inserting Employee Data

Description of Figure 5-7 follows
Description of "Figure 5-7 Inserting Employee Data"

5.4 Deleting an Employee Record

The steps for deleting a record are similar to those for editing and inserting a record:

Use the method created in Creating a Method to Identify an Employee Record to identify a particular employee row. This is used to identify the row to be deleted.

Create a method that deletes an employee record from the database.

Add a link to the main application page for each row, allowing a user to click to delete the employee in that row. The link takes the user to a delete_action.jsp, with the ID of the employee whose record is to be deleted.

To delete the employee from the database, create a JSP page to call the delete method created in Step 2.

This section discusses the following tasks related to deleting employee data:

Creating a Method for Deleting Data

Adding a Link to Delete an Employee

Creating a JSP Page to Handle a Delete Action

5.4.1 Creating a Method for Deleting Data

The method created in the following steps is used to delete employee records by ID:

Open DataHandler.java in the Java Source Editor.

Declare a new method that identifies the employee record to be deleted:

public String deleteEmployeeById(int id) throws SQLException {

}

Connect to the database as before.

getDBConnection();

Create a Statement object, define a ResultSet type as before, and formulate the SQL statement. Add a trace message to assist with debugging.

stmt =
  conn.createStatement(ResultSet.TYPE_SCROLL_SENSITIVE,
                       ResultSet.CONCUR_READ_ONLY);
sqlString = "DELETE FROM Employees WHERE employee_id = " + id;
System.out.println("\nExecuting: " + sqlString);

Run the SQL statement.

stmt.execute(sqlString);

If the SQL statement runs without any errors, return the word, Success.

return "success";

Example 5-4 shows the code for the deleteEmployeeById() method.

Example 5-4 Method for Deleting an Employee Record

public String deleteEmployeeById(int id) throws SQLException {
        getDBConnection();
        stmt = conn.createStatement(ResultSet.TYPE_SCROLL_SENSITIVE,
                                ResultSet.CONCUR_READ_ONLY);
    sqlString = "DELETE FROM Employees WHERE employee_id = " + id;
    System.out.println("\nExecuting: " + sqlString);
    stmt.execute(sqlString);
    return "success";
}

5.4.2 Adding a Link to Delete an Employee

In the following instructions, you add a link to each row of the employees table on the employees.jsp page. Clicking on that link will delete all employee data for that row.

Open employees.jsp in the Visual Editor.

In the column you created to contain the Edit link, add another link for deleting the row. To do this, double-click the scriptlet that is inside the Employees table, to display the Scriptlet Properties dialog box.

Modify the scriptlet to include a link to a delete_action.jsp page. The modified scriptlet should contain the following code:

    while (rset.next ())
    {
    out.println("<tr>");
      out.println("<td>" +
      rset.getString("first_name") + "</td><td> " +
      rset.getString("last_name") + "</td><td> " +
      rset.getString("email") + "</td><td> " +
      rset.getString("job_id") + "</td><td>" +
      rset.getString("phone_number") + "</td><td>" +
      rset.getDouble("salary") +
      "</td><td> <a href=\"edit.jsp?empid=" + rset.getInt(1) +
      "\">Edit</a>   <a href=\"delete_action.jsp?empid=" +
      rset.getInt(1) + "\">Delete</a></td>");
    out.println("<tr>");
    }

Save employees.jsp.

5.4.3 Creating a JSP Page to Handle a Delete Action

In the following steps, you create the delete_action.jsp page, which is a page that only processes the delete operation. There are no visual elements on this page.

Create a JSP page and call it delete_action.jsp.

Add a jsp:usebean tag. As before, enter empsbean as the ID, and hr.DataHandler as the Class. Set the Scope to session, and click OK.

Add a Scriptlet to the page. Enter the following code into the Insert Scriptlet dialog box:

Integer employee_id =
 new Integer(request.getParameter("empid"));
empsbean.deleteEmployeeById(employee_id.intValue());

Drag Forward from the Component Palette to add a jsp:forward tag to the page. In the Insert Forward dialog box, enter employees.jsp.

Save your work.

Run the project and try deleting an employee. Figure 5-8 shows the links for deleting employee records from the employees.jsp.

Figure 5-8 Link for Deleting an Employee from employees.jsp

Description of Figure 5-8 follows
Description of "Figure 5-8 Link for Deleting an Employee from employees.jsp"

If you click Delete for any of the employee records, then that employee record will be deleted.

5.5 Exception Handling

A SQLException object instance provides information on a database access error or other errors. Each SQLException instance provides many types of information, including a string describing the error, which is used as the Java Exception message, available via the getMessage method.

The sample application uses try and catch blocks, which are the Java mechanism for handling exceptions. With Java, if a method throws an exception, there needs to be a mechanism to handle it. Generally, a catch block catches the exception and specifies the course of action in the event of an exception, which could simply be to display the message.

Each JDBC method throws a SQLException if a database access error occurs. For this reason, any method in an application that executes such a method must handle the exception.

All the methods in the sample application include code for handling exceptions. For example, the getDBConnection, which is used to get a connection to the database, throws SQLException, as does the getAllEmployees method as follows:

public ResultSet getAllEmployees() throws SQLException {
}

For an example of code used to catch and handle SQLExceptions, refer to the code in the authenticateUser method in the DataHandler.java class. In this example, a try block contains the code for the work to be done to authenticate a user, and a catch block handles the case where the authentication fails.The following sections describe how to add code to the sample application to catch and handle SQLExceptions.

5.5.1 Adding Exception Handling to Java Methods

To handle SQL exceptions in the methods in the sample application, do the following:

Ensure that the method throws SQLException. For example, the method:

public ResultSet getAllEmployees() throws SQLException

Use try and catch blocks to catch any SQLExceptions. For example, in the getAllEmployees method, enclose your existing code in a try block, and add a catch block as follows:

public ResultSet getAllEmployees() throws SQLException {
  try {
    getDBConnection();
    stmt =
      conn.createStatement(ResultSet.TYPE_SCROLL_SENSITIVE,
                           ResultSet.CONCUR_READ_ONLY);
    sqlString = "SELECT * FROM Employees order by employee_id";
    System.out.println("\nExecuting: " + sqlString);
    rset = stmt.executeQuery(sqlString);
  }
  catch (SQLException e) {
    e.printStackTrace();
  }
  return rset;
}

As another example, the deleteEmployee method rewritten to use try and catch blocks would return "success" only if the method was successful, that is, the return statement is enclosed in the try block. The code could be as follows:

  public String deleteEmployeeById(int id) throws SQLException {

    try {
      getDBConnection();
      stmt =
        conn.createStatement(ResultSet.TYPE_SCROLL_SENSITIVE,
                             ResultSet.CONCUR_READ_ONLY);
      sqlString = "delete FROM Employees where employee_id = " + id;
      System.out.println("\nExecuting: " + sqlString);

      stmt.execute(sqlString);
      return "success";
    }
    catch (SQLException e) {
      e.printStackTrace();
    }
  }

5.5.2 Creating a Method for Handling Any SQLException

As a refinement to the code for the sample application, you can create a method that can be used in any method that might throw a SQLException, to handle the exception. As an example, the following method could be called in the catch block of any of the methods in the sample application. This method cycles through all the exceptions that have accumulated, printing a stack trace for each.

Example 5-5 Adding a Method to Handle Any SQLException in the Application

public void logException( SQLException ex )
{
  while ( ex != null ) {
    ex.printStackTrace();
    ex = ex.getNextException();
  }
}

In addition, in the catch block, you can return text that explains why the method has failed. The catch block of a method could therefore be written as follows:

catch ( SQLException ex )  {
  logException( ex );
  return "failure";
}

To add this feature to your application:

In the DataHandler.java, add a logException method.

Edit each of the methods to include try and catch blocks.

In the catch block of each method, run the logException method.

For methods that have a return value of String, include a return statement to return a message indicating that the method has failed such as:

return "failure";

5.6 Navigation in the Sample Application

The web.xml file is the deployment descriptor file for a web application. One section of the web.xml file can be used for defining a start page for the application, for example:

<web-app>
...
  <welcome-file>
    myWelcomeFile.jsp
  </welcome-file>
...
</web-app>

If you do not define a welcome page in your web.xml file, generally a file with the name index, with extension .html, .htm, or .jsp if there is one, is used as the starting page. With JDeveloper, you can define which page is to be the default run target for the application, that is, the page of the application that is displayed first, by defining it in the properties of the project.

Once the application has started, and the start page has been displayed, navigation through the application is achieved using the following scheme:

Links, in the form of HTML anchor tags, define a target for the link, usually identifying another JSP page to which to navigate, and some text for the link.

HTML submit buttons, are used to submit forms on the pages, such as forms for entering new or changed data.

jsp:forward tags, which are executed on JSP pages that handle queries and forms, to forward to either the same JSP page again, or another JSP page.

5.6.1 Creating a Starting Page for an Application

In the following steps, you create the index.jsp page, which will be the default starting page for the application. The page does not include any display elements, and simply forwards the user to the application login page, login.jsp. To do this you use the jsp:forward tag. A jsp:forward tag runs on JSP pages that handle queries and forms, to forward to either the same JSP page again, or another JSP page.

Create a new JSP page and call it index.jsp.

For the sample application, we will not add any text to this page. From the JSP page of the Component Palette, drag Forward to include a jsp:forward tag in the page.

In the Insert Forward dialog box for the forward tag, enter login.jsp as the Page.

You can now specify this new page as the default target for the application as follows:

In the Application Navigator, right-click the View project and choose Project Properties.

In the displayed tree, select Run/Debug/Profile. In the Run/Debug/Profile area, ensure that Use Project Settings is selected, and in the Run Configurations area, ensure that Default Configurations is selected. Click Edit.

In the Edit Launch Settings dialog box, select Launch Settings. In the Launch Settings area on the right, click Browse next to the Default Run Target field and navigate to find the new index.jsp page you just created and click OK. Then click OK again to close the dialog box.

You can now run your application by right-clicking in the View project and select Run from the shortcut menu. The application runs and runs index.jsp, which has been set as the default launch target for the application. The index.jsp forwards you directly to the login page, login.jsp, which is displayed in your browser.

6 Enhancing the Application: Advanced JDBC Features

This chapter describes additional functionality that you can use in your Java application. Some of these features have not been implemented in the sample application, while some features are enhancements you can use in your code to improve performance.

This chapter includes the following sections:

Using Dynamic SQL

Calling Stored Procedures

Using Cursor Variables

6.1 Using Dynamic SQL

Dynamic SQL, or generating SQL statements on the fly, is a constant need in a production environment. Very often, and especially in the matter of updates to be performed on a database, the final query is not known until run time.

For scenarios where many similar queries with differing update values must be run on the database, you can use the OraclePreparedStatement object, which extends the Statement object. This is done by substituting the literal update values with bind variables. You can also use stored PL/SQL functions on the database by calling stored procedures through the OracleCallableStatement object.

This section discusses the following topics:

Using OraclePreparedStatement

Using OracleCallableStatement

Using Bind Variables

6.1.1 Using OraclePreparedStatement

To run static SQL queries on the database, you use the Statement object. However, to run multiple similar queries or perform multiple updates that affect many columns in the database, it is not feasible to hard-code each query in your application.

You can use OraclePreparedStatement when you run the same SQL statement multiple times. Consider a query like the following:

SELECT * FROM Employees WHERE ID=xyz;

Every time the value of xyz in this query changes, the SQL statement needs to be compiled again.

If you use OraclePreparedStatement functionality, the SQL statement you want to run is precompiled and stored in a PreparedStatement object, and you can run it as many times as required without compiling it every time it is run. If the data in the statement changes, you can use bind variables as placeholders for the data and then provide literal values at run time.

Consider the following example of using OraclePreparedStatement:

Example 6-1 Creating a PreparedStatement

OraclePreparedStatement pstmt = conn.prepareStatement("UPDATE Employees
                                SET salary = ? WHERE ID = ?");
   pstmt.setBigDecimal(1, 153833.00)
   pstmt.setInt(2, 110592)

The advantages of using the OraclePreparedStatement interface include:

You can batch updates by using the same PreparedStatement object

You can improve performance because the SQL statement that is run many times is compiled only the first time it is run.

You can use bind variables to make the code simpler and reusable.

6.1.2 Using OracleCallableStatement

You can access stored procedures on databases using the OracleCallableStatement interface. This interface extends the OraclePreparedStatement interface. The OracleCallableStatement interface consists of standard JDBC escape syntax to call stored procedures. You may use this with or without a result parameter. However, if you do use a result parameter, it must be registered as an OUT parameter. Other parameters that you use with this interface can be either IN, OUT, or both.

These parameters are set by using accessor methods inherited from the OraclePreparedStatement interface. IN parameters are set by using the setXXX methods and OUT parameters are retrieved by using the getXXX methods, XXX being the Java data type of the parameter.

A CallableStatement can also return multiple ResultSet objects.

As an example, you can create an OracleCallableStatement to call the stored procedure called foo, as follows:

Example 6-2 Creating a CallableStatement

OracleCallableStatement cs = (OracleCallableStatement)
conn.prepareCall("{call foo(?)}");

You can pass the string bar to this procedure in one of the following two ways:

cs.setString(1,"bar"); // JDBC standard
// or...
cs.setStringAtName(X, "value"); // Oracle extension

6.1.3 Using Bind Variables

Bind variables are variable substitutes for literals in a SQL statement. They are used in conjunction with OraclePreparedStatement and OracleCallableStatement to specify parameter values that are used to build the SQL statement. Using bind variables has remarkable performance advantages in a production environment.

For PL/SQL blocks or stored procedure calls, you can use the following qualifiers to differentiate between input and output variables: IN, OUT, and IN OUT. Input variable values are set by using setXXX methods and OUT variable values can be retrieved by using getXXX methods, where XXX is the Java data type of the values. This depends on the SQL data types of the columns that you are accessing in the database.

6.2 Calling Stored Procedures

Oracle Java Database Connectivity (JDBC) drivers support the processing of PL/SQL stored procedures and anonymous blocks. They support Oracle PL/SQL block syntax and most of JDBC escape syntax. The following PL/SQL calls would work with any Oracle JDBC driver:

Example 6-3 Calling Stored Procedures

// JDBC syntaxCallableStatement cs1 = conn.prepareCall
                        ( "{call proc (?,?)}" ) ; // stored proc
CallableStatement cs2 = conn.prepareCall
                        ( "{? = call func (?,?)}" ) ; // stored func

// Oracle PL/SQL block syntax
CallableStatement cs3 = conn.prepareCall
                        ( "begin proc (?,?); end;" ) ; // stored proc
CallableStatement cs4 = conn.prepareCall
                        ( "begin ? := func(?,?); end;" ) ; // stored func

As an example of using the Oracle syntax, here is a PL/SQL code snippet that creates a stored function. The PL/SQL function gets a character sequence and concatenates a suffix to it:

Example 6-4 Creating a Stored Function

create or replace function foo (val1 char)
return char as
begin
return val1 || 'suffix';
end;

You can call this stored function in a Java program as follows:

Example 6-5 Calling a Stored Function in Java

OracleDataSource ods = new OracleDataSource();
ods.setURL("jdbc:oracle:thin:@<hoststring>");
ods.setUser("hr");
ods.setPassword("hr");
Connection conn = ods.getConnection();
CallableStatement cs = conn.prepareCall ("begin ? := foo(?); end;");
cs.registerOutParameter(1,Types.CHAR);
cs.setString(2, "aa");
cs.executeUpdate();
String result = cs.getString(1);

The following sections describe how you can use stored procedures in the sample application in this guide:

Creating a PL/SQL Stored Procedure in JDeveloper

Creating a Method to Use the Stored Procedure

Allowing Users to Choose the Stored Procedure

Calling the Stored Procedure from the Application

6.2.1 Creating a PL/SQL Stored Procedure in JDeveloper

JDeveloper allows you to create stored procedures in the database through the Database Navigator. In these steps, you create a stored procedure that can be used as an alternative way of inserting an employee record in the sample application.

Select the DatabaseNavigatorName tab to view the Database Navigator.

Expand the database connection node (by default called Connection1) to see the objects in the HR database.

Right-click Procedures, and select New Procedure.

In the Create PL/SQL Procedure dialog, enter insert_employee as the object name. Click OK.

The skeleton code for the procedure is displayed in the Source Editor.

After the procedure name, enter the following lines of code:

PROCEDURE    "INSERT_EMPLOYEE" (p_first_name  employees.first_name%type,
  p_last_name    employees.last_name%type,
  p_email        employees.email%type,
  p_phone_number employees.phone_number%type,
  p_job_id       employees.job_id%type,
  p_salary       employees.salary%type
)

After the BEGIN statement, replace the line that reads NULL with the following:

  INSERT INTO Employees VALUES (EMPLOYEES_SEQ.nextval, p_first_name ,
    p_last_name , p_email , p_phone_number, SYSDATE, p_job_id,
    p_salary,.30,100,80);

You can see that the statement uses the same hard-coded values that are used for the last three columns in the addEmployee method in the DataHandler.java class.

Add the procedure name in the END statement:

END insert_employee;

Save the file, and check whether there are any compilation errors.

The complete code for the stored procedure is shown in Example 6-6.

Example 6-6 Creating a PL/SQL Stored Procedure to Insert Employee Data

PROCEDURE    "INSERT_EMPLOYEE" (p_first_name  employees.first_name%type,
  p_last_name    employees.last_name%type,
  p_email        employees.email%type,
  p_phone_number employees.phone_number%type,
  p_job_id       employees.job_id%type,
  p_salary       employees.salary%type
)
AS
BEGIN
  INSERT INTO Employees VALUES (EMPLOYEES_SEQ.nextval, p_first_name ,
    p_last_name , p_email , p_phone_number, SYSDATE, p_job_id,
    p_salary,.30,100,80);
END insert_employee;

6.2.2 Creating a Method to Use the Stored Procedure

In these steps, you add a method to the DataHandler.java class that can be used as an alternative to the addEmployee method. The new method you add here makes use of the insert_employee stored procedure.

Select the Application tab to display the Application Navigator.

If the DataHandler.java file is not already open in the Java Source Editor, double-click it to open it.

Import the CallableStatement interface as follows:

import java.sql.CallableStatement;

After the addEmployee method, add the declaration for the addEmployeeSP method.

public String addEmployeeSP(String first_name, String last_name,
  String email, String phone_number, String job_id,
  int salary) throws SQLException {
}

The method signature is the same as that for addEmployee.

Inside the method, add a try block, and inside that, connect to the database.

try {
  getDBConnection();
}

In addition, inside the try block, create the SQL string:

sqlString = "begin hr.insert_employee(?,?,?,?,?,?); end;";

The question marks (?) in the statement are bind variables, acting as placeholders for the values of first_name, last_name, and so on expected by the stored procedure.

Create the CallableStatement:

CallableStatement callstmt = conn.prepareCall(sqlString);

Set the IN parameters:

  callstmt.setString(1, first_name);
  callstmt.setString(2, last_name);
  callstmt.setString(3, email);
  callstmt.setString(4, phone_number);
  callstmt.setString(5, job_id);
  callstmt.setInt(6, salary);

Add a trace message, and run the callable statement.

  System.out.println("\nInserting with stored procedure: " +
                      sqlString);
  callstmt.execute();

Add a return message:

  return "success";

After the try block, add a catch block to trap any errors. Call the logException created in Example 5-5.

catch ( SQLException ex ) {
  System.out.println("Possible source of error: Make sure you have created the stored procedure");
  logException( ex );
  return "failure";
}

Save DataHandler.java.

The complete method is shown in Example 6-7.

Note:

If you have not added the logException() method (see Example 5-5), JDeveloper will indicate an error by showing a red curly line under logException(ex). This method must be present in the DataHandler.java class before you proceed with compiling the file.

Example 6-7 Using PL/SQL Stored Procedures in Java

public String addEmployeeSP(String first_name, String last_name,
  String email, String phone_number, String job_id,
  int salary) throws SQLException {

  try {
    getDBConnection();
    sqlString = "begin hr.insert_employee(?,?,?,?,?,?); end;";
    CallableStatement callstmt = conn.prepareCall(sqlString);
    callstmt.setString(1, first_name);
    callstmt.setString(2, last_name);
    callstmt.setString(3, email);
    callstmt.setString(4, phone_number);
    callstmt.setString(5, job_id);
    callstmt.setInt(6, salary);
    System.out.println("\nInserting with stored procedure: " +
                       sqlString);

    callstmt.execute();
    return "success";
  }
  catch ( SQLException ex ) {
    System.out.println("Possible source of error: Make sure you have created the stored procedure");
    logException( ex );
    return "failure";
  }
}

6.2.3 Allowing Users to Choose the Stored Procedure

The steps in this section add a radio button group to the insert.jsp page, which allows a user to choose between inserting an employee record using the stored procedure, or by using a SQL query in Java code.

Open insert.jsp in the Visual Editor, if it is not already open.

Create a new line after the Insert Employee Record heading. With the cursor on this new line, drag UseBean from the JSP page of the Component Palette to add a jsp:useBean tag to the page. Enter empsbean as the ID, browse to select hr.DataHandler as the Class, and set the Scope to session. With the UseBean still selected on the page, set the style of this line to None instead of Heading 3.

Drag a Radio Button component from the HTML Forms page of the Component Palette onto the page inside the form above the table. In the Insert Radio Button dialog, enter useSP as the Name, false as the Value, and select Checked. Click OK.

In the Visual Editor, position the cursor to the right of the button, and enter text to describe the purpose of the button, for example, 'Use only JDBC to insert a new record'.

Press Enter at the end of the current line to create a new line.

Drag a second Radio Button below the first one. In the Insert Radio Button dialog, use useSP as the Name, true as the Value, and ensure that the Checked checkbox is not selected.

In the Visual Editor, position the cursor directly to the right of the button, and enter text to describe the purpose of the button, for example, 'Use stored procedure called via JDBC to insert a record'.

Save the page.

Figure 6-1 shows insert.jsp with the radio button that provides the option to use a stored procedure.

Figure 6-1 Adding a Link to Provide the Stored Procedure Option

Description of Figure 6-1 follows
Description of "Figure 6-1 Adding a Link to Provide the Stored Procedure Option"

6.2.4 Calling the Stored Procedure from the Application

The steps in this section modify the insert_action.jsp file, which processes the form on the insert.jsp page, to use the radio button selection and select the appropriate method for inserting a new employee record.

Open insert_action.jsp in the Visual Editor, if it is not already open.

Double-click the scriptlet to invoke the Scriptlet Properties dialog box and add a new variable after the salary variable, as follows:

String useSPFlag = request.getParameter("useSP");

Below that, still in the Scriptlet Properties dialog box, replace the existing empsbean.addEmployee line with the following lines of code to select the addEmployeeSP method or the pure JDBC addEmployee method to insert the record.

if ( useSPFlag.equalsIgnoreCase("true"))
  empsbean.addEmployeeSP(first_name, last_name, email,
  phone_number, job_id, salary.intValue());
// otherwise use pure JDBC insert
else
  empsbean.addEmployee(first_name, last_name, email,
  phone_number, job_id, salary.intValue());

Save insert_action.jsp.

You can now run the application and use the radio buttons on the insert page to choose how you want to insert the new employee record. In a browser, the page will appear as shown in Figure 6-2.

Figure 6-2 Using Stored Procedures to Enter Records

Description of Figure 6-2 follows
Description of "Figure 6-2 Using Stored Procedures to Enter Records"

6.3 Using Cursor Variables

Oracle JDBC drivers support cursor variables with the REF CURSOR types, which are not a part of the JDBC standard. REF CURSOR types are supported as JDBC result sets.

A cursor variable holds the memory location of a query work area, rather than the contents of the area. Declaring a cursor variable creates a pointer. In SQL, a pointer has the data type REF x, where REF is short for REFERENCE and x represents the entity being referenced. A REF CURSOR, then, identifies a reference to a cursor variable. Because many cursor variables might exist to point to many work areas, REF CURSOR can be thought of as a category or data type specifier that identifies many different types of cursor variables. A REF CURSOR essentially encapsulates the results of a query.

Oracle does not return ResultSets. To access data returned by a query, you use CURSORS and REF CURSORS. CURSORS contain query results and metadata. A REF CURSOR (or CURSOR variable) data type contains a reference to a cursor. It can be passed between the RDBMS and the client, or between PL/SQL and Java in the database. It can also be returned from a query or a stored procedure.

Note:

REF CURSOR instances are not scrollable.

This section contains the following subsections:

Oracle REF CURSOR Type Category

Accessing REF CURSOR Data

Using REF CURSOR in the Sample Application

6.3.1 Oracle REF CURSOR Type Category

To create a cursor variable, begin by identifying a type that belongs to the REF CURSOR category. For example:

dept_cv DeptCursorTyp
...

Then, create the cursor variable by declaring it to be of the type DeptCursorTyp:

Example 6-8 Declaring a REF CURSOR Type

DECLARE TYPE DeptCursorTyp IS REF CURSOR

REF CURSOR, then, is a category of data types, rather than a particular data type. Stored procedures can return cursor variables of the REF CURSOR category. This output is equivalent to a database cursor or a JDBC result set.

6.3.2 Accessing REF CURSOR Data

In Java, a REF CURSOR is materialized as a ResultSet object and can be accessed as follows:

Example 6-9 Accessing REF Cursor Data in Java

import oracle.jdbc.*;
...
CallableStatement cstmt;
ResultSet cursor;

// Use a PL/SQL block to open the cursor
cstmt = conn.prepareCall
         ("begin open ? for select ename from emp; end;");

cstmt.registerOutParameter(1, OracleTypes.CURSOR);
cstmt.execute();
cursor = ((OracleCallableStatement)cstmt).getCursor(1);

// Use the cursor like a normal ResultSet
while (cursor.next ())
    {System.out.println (cursor.getString(1));}

In the preceding example:

A CallableStatement object is created by using the prepareCall method of the connection class.

The callable statement implements a PL/SQL procedure that returns a REF CURSOR.

As always, the output parameter of the callable statement must be registered to define its type. Use the type code OracleTypes.CURSOR for a REF CURSOR.

The callable statement is run, returning the REF CURSOR.

The CallableStatement object is cast to OracleCallableStatement to use the getCursor method, which is an Oracle extension to the standard JDBC application programming interface (API), and returns the REF CURSOR into a ResultSet object.

6.3.3 Using REF CURSOR in the Sample Application

In the following sections, you enhance the sample application to display a dynamically-generated list of job IDs and job titles in the Job field when they are inserting a new employee record.

Creating a Package in the Database

Creating a Database Function

Calling the REF CURSOR from a Method

Displaying a Dynamically Generated List

To do this, you create a database function, GET_JOBS, that uses a REF CURSOR to retrieve a result set of jobs from the Jobs table. A new Java method, getJobs, calls this database function to retrieve the result set.

6.3.3.1 Creating a Package in the Database

The following steps create a new package in the database to hold a REF CURSOR declaration.

Select the DatabaseNavigatorName tab to view it in the Navigator.

Expand the Connection1 node to view the list of database objects. Scroll down to Packages. Right-click Packages and select New Package.

In the Create PL/SQL Package dialog, enter JOBSPKG as the name. Click OK. The package definition is displayed in the Source Editor.

Position the cursor at the end of the first line and press Enter to create a new line. In the new line, declare a REF CURSOR as follows:

    TYPE ref_cursor IS REF CURSOR;

Save the package.

The code for the package is shown in Example 6-10:

Example 6-10 Creating a Package in the Database

PACKAGE "JOBSPKG" AS
    TYPE ref_cursor IS REF CURSOR;
END;

6.3.3.2 Creating a Database Function

These steps create a database function GET_JOBS that uses a REF CURSOR to retrieve a result set of jobs from the Jobs table.

In the Database Navigator, again expand the necessary nodes to view the objects in the HR database. Right-click Functions and select New Function from the shortcut menu.

In the Create PL/SQL Function dialog, enter GET_JOBS as the name. Click OK. The definition for the GET_JOBS function displays in the Source Editor

In the first line of the function definition, substitute JobsPkg.ref_cursor as the return value, in place of VARCHAR2.

After the AS keyword, enter the following:

 jobs_cursor JobsPkg.ref_cursor;

In the BEGIN block enter the following code to replace the current content:

  OPEN jobs_cursor FOR
  SELECT job_id, job_title FROM jobs;
  RETURN jobs_cursor;

Save the function

The code for the function is shown in Example 6-11.

Example 6-11 Creating a Stored Function

FUNCTION    "GET_JOBS"
RETURN JobsPkg.ref_cursor
AS jobs_cursor JobsPkg.ref_cursor;
BEGIN
  OPEN jobs_cursor FOR
  SELECT job_id, job_title FROM jobs;
  RETURN jobs_cursor;
END;

6.3.3.3 Calling the REF CURSOR from a Method

These steps create a Java method, getJobs, in the DataHandler class that calls the GET_JOBS function to retrieve the result set.

Double-click DataHandler.java to open it in the Source Editor if it is not already open.

Enter the method declaration.

public ResultSet getJobs() throws SQLException {

}

Within the method body, connect to the database.

  getDBConnection();

Following the connection, declare a new variable, jobquery:

  String jobquery = "begin ? := get_jobs; end;";

Create a CallableStatement using the prepareCall method:

  CallableStatement callStmt = conn.prepareCall(jobquery);

Register the type of the OUT parameter, using an Oracle-specific type.

  callStmt.registerOutParameter(1, OracleTypes.CURSOR);

When you specify that you want to use an Oracle-specific type, JDeveloper displays a message asking you to use Alt+Enter to import oracle.jdbc.OracleTypes. Press Alt+Enter, and then select OracleTypes (oracle.jdbc) from the list that appears.

Run the statement and return the result set.

  callStmt.execute();
  rset = (ResultSet)callStmt.getObject(1);

Enclose the code entered so far in a try block.

Add a catch block to catch any exceptions, and call your logException method as well.

catch ( SQLException ex ) {
  logException( ex );
}

After the close of the catch block, return the result set.

return rset;

Make the file to check for syntax errors.

The code for the getJobs method is as follows:

  public ResultSet getJobs() throws SQLException {
  try {
    getDBConnection();
    String jobquery = "begin ? := get_jobs; end;";
    CallableStatement callStmt = conn.prepareCall(jobquery);
    callStmt.registerOutParameter(1, OracleTypes.CURSOR);
    callStmt.execute();
    rset = (ResultSet)callStmt.getObject(1);
  } catch ( SQLException ex ) {
  logException( ex );
  }
  return rset;
  }

6.3.3.4 Displaying a Dynamically Generated List

To create the drop down list displaying the list of job IDs and job titles in the Insert page, you hard-coded the job IDs and job titles. In the following steps, you replace this with a dynamically-generated list provided by the REF CURSOR created in the previous section.

Double-click insert.jsp in the Application Navigator to open it in the Visual Editor, if it is not already open.

Drag a Page Directive onto the page to the right of the useBean tag. In the Insert Page Directive dialog box, enter java as the Language, and in the Import field, browse to select java.sql.ResultSet. Click OK.

Drag a scriptlet onto the page next to the Page Directive. In the Insert Scriptlet dialog box, add the following code to execute the getJobs method and return a result set containing a list of jobs.

ResultSet rset = empsbean.getJobs();

Select the ListBox component in the page, and click Scriptlet in the JSP Component Palette. (You need not drag and drop the scriptlet onto the page in this case.) The Insert Scriptlet dialog box appears.

Enter the following code into the Insert Scriptlet dialog box. Click OK.

  while (rset.next ())
   {
    out.println("<option value=" + rset.getString("job_id") + ">" +
    rset.getString("job_title") + "</option> "  );
   }

Remove the hard-coded values as follows.

With the ListBox component still selected, in the Structure window scroll to Job field. Examine the list of hard-coded options below the select keyword. Delete each of the options, ensuring that you retain the scriptlet.

Figure 6-3 Structure View of Dropdown ListBox Options

Description of Figure 6-3 follows
Description of "Figure 6-3 Structure View of Dropdown ListBox Options"

Save the page.

Now run the application, click to insert a new employee and use the list to display a list of available jobs. Figure 6-4 shows the dynamic jobs list in the browser.

Figure 6-4 Dynamically Generated List in Browser

Description of Figure 6-4 follows
Description of "Figure 6-4 Dynamically Generated List in Browser"

7 Creating a Master-Detail Application Using JPA and Oracle ADF

This chapter describes how to create a master-detail application usingJava Persistence API(JPA)and Oracle Application Developer Framework (Oracle ADF) in the following sections:

Overview of the Master-Detail Application

Using Java Persistence API (JPA) with Oracle ADF

Building the Data Model with EJB 3.0 Using the EJB Diagramer

Create a New Project for the User Interface

Creating the Page Flow

Creating a Master-Detail JavaServer Faces Page

Creating a Query and Edit Page

Running the Application

Note:

To develop, the master-detail application as described in this chapter, you must have an installation of Oracle JDeveloper 11g or later Studio Edition.

7.1 Overview of the Master-Detail Application

A master-detail application allows you to view data from related tables at the same time. The records from a master table can be viewed along with related records from the detail table. If provisioning to edit the master-detail data is built into the application, you can also edit data from both the tables from a common interface. The master-detail application created in this chapter consists of:

JPA/EJB middle-tier components exposed through the ADF binding layer, to allow data in the table from the HR schema to be accessed and updated. This is in one project called model.

A user interface (UI), or view, that consists of a set of JavaServer Faces(JSF) pages that serve as the UI for the application. This will be in a project called view.

The model and view projects are based on the Java EE Model-View-Controller (MVC) design pattern, that is easily implemented using Oracle ADF.

Figure 7-1 shows the relationships among the items developed for this application.

Figure 7-1 Master Detail Application Pages

Description of Figure 7-1 follows
Description of "Figure 7-1 Master Detail Application Pages"

This application accesses the HR schema on Oracle Database. It uses the departments table as the master table to display detail data from the employees table. This chapter describes how you can use Oracle ADF with JDeveloper to create this application.

7.2 Using Java Persistence API (JPA) with Oracle ADF

Oracle ADF is an end-to-end application framework that builds on Java EE standards and open-source technologies to simplify and accelerate creating service-oriented applications. You can use Oracle ADF to develop enterprise solutions that search, display, create, modify, and validate data using web, wireless, desktop, or web services interfaces. Used in tandem, Oracle JDeveloper 11g and Oracle ADF give you an environment that covers the full development lifecycle from design to deployment, with drag-and-drop data binding, visual UI design, and team development features built-in.

The following subsections introduce Java Persistence API (JPA) and some of the Oracle ADF features that you will use to create the master detail application:

Java Persistence API (JPA)

Oracle ADF Faces

ADF Data Controls

See Also:

http://www.oracle.com/technology/products/adf/pdf/ADF_11_overview.pdf for more information on Oracle ADF architecture

http://www.oracle.com/technology/products/adf/index.html for a compilation of resources on Oracle ADF

7.2.1 Java Persistence API (JPA)

JPA is part of the Java EE specification that deals with object/relational mapping and data persistence between Java and databases.

The Java Persistence consists of:

The Java Persistence API or JPA

The query language

Object or relational mapping metadata

7.2.2 Oracle ADF Faces

Oracle ADF Faces is based on the JavaServer Faces (JSF) JSR 127 specification. Oracle ADF Faces components are used in the user interfaces of the application. These components can be used in any IDE that supports JSF.

You can use Oracle ADF Faces to determine a consistent look and feel for your application. This allows you to focus on user interface interaction rather than look and feel compliance. ADF Faces components also support multi–language and translation implementation as well as accessibility features.

JDeveloper provides several design tools, wizards, special dialogs, and property editors that help you insert and use ADF Faces components in your pages. For example, the Visual Editor lets you design user interfaces by dragging and dropping components from the Component Palette. If you are familiar with XML or JSP/HTML coding, you can also edit the source of the page files to insert ADF Faces component tags.

7.2.3 ADF Data Controls

Oracle ADF data controls permit the application client to access business services defined by the model object layer. Business services can be any collection, value, or action that your model project defines. At runtime, the ADF Model layer reads the information describing the data controls and bindings from appropriate XML files and implements the two-way connection between the user interface and the business service.

7.3 Building the Data Model with EJB 3.0 Using the EJB Diagramer

In the next few steps, you create an application in JDeveloper and create a data model for your application.

Creating an Application and Project

Creating the Persistence Model

Creating the Data Model

Running the Java Service outside Java EE container

7.3.1 Creating an Application and Project

Before you proceed to developing the master detail application, you must create a Connection object HRConn that establishes a connection between the application and the database. For instructions to create a Connection object, refer to Chapter 3.

From the File menu, select New to display the New Gallery. From the General category, select Application and then select Generic Application. The Create Generic Application wizard is displayed.

Enter HR_EJB_JPA_App as the Name of the application, enter oracle as the Application Package Prefix, and click Next.

In the Name your Generic project screen, enter EJBModel as the Project Name and click Finish.

In the Navigator pane, click the Database Navigator tab. Select the HRConn connection in the IDE connections list and drag and drop it inside the HR_EJB_JPA_App node to make the connection available for your application.

You now have an application called HR_EJB_JPA_App, which contains a project called EJBModel.

7.3.2 Creating the Persistence Model

In the model project, you will create the persistence model for hr.Departments and hr.Employees table using EJB 3.0 entity beans.

In the JDeveloper Application Navigator, select the EJBModel project.

From the File menu, select New to display the New Gallery. Expand the Business Tier category, and select EJB. In the Items list, select Entities from Tables. Click OK.

In Select EJB Version, select EJB 3.0 -- JPA Entities as the EJB version, then Next. Click Next to skip the Persistence Unit page.

In the Type of Connection page choose the Online Database Connection option and accept the default Offline Database name, then click Next.

In the Database Connection Details page, select HRConn as the connection to use. Click Next.

Click Query to retrieve the available objects for the HR schema. Then move DEPARTMENTS and EMPLOYEES to the Selected list. Click Next.

In this step, make sure the package name is oracle. Click Next, then Finish.

Right click the EJBModel node in the Application Navigator and select New.

In the New Gallery select Business Tier, then EJB as the category and double click EJB Diagram (JPA/EJB 3.0).

In the Create EJB Diagram dialog, change the default name for the diagram (EJB Diagram1) to EJB 3 and verify oracle is the Package name. Click OK.

On the Associate Diagram With Persistence Unit dialog, click OK to accept the proposed Persistence Unit EJBModel (EJBModel.jpr). A new empty diagram opens in the diagram editor.

Select the Departments and Employees entities from the Application Navigator then drag and drop them onto the diagram. Reorganize the layout of the diagram to have both entities horizontally aligned. Save all your work.

Figure 7-2 Persistence Model

7.3.3 Creating the Data Model

In this section, you create a session bean that implements a method to find employee and department records.

Select EJB Components from the Component Palette library and open the EJB Nodes. Select the Session Bean component and drag and drop it onto the diagram. The Create Session Bean Wizard opens.

In the EJB Name and Options step, set the EJB Name to HRFacade and make sure that the following values are properly set:

Session Type: Stateless

Transaction Type: Container

Generate Session Facade Method is checked

Entity Implementation: JPA Entities

Persistence Unit: EJBModel

Click Next.

Expand the Employees and Departments nodes and deselect the findAllByRange method for each entity. Click Next.

In the Class Definition step, make sure that the full name for Bean Class is oracle.HRFacadeBean. Click Next.

In the following step, we have both Remote and Local interface implementation selected. The remote interface is used for client applications that run in a separate virtual machine, such as Java clients whereas local interface is used for client applications that run in the same virtual machine, such as Web clients. Click Next to review the summary of the created classes and then click Finish.

The session bean is made up of three files: HRFacadeBean - contains the session bean code. HRFacade - describes the capabilities of the bean for remote clients and HRFacadeLocal describes the capabilities for the local client.

Double click the Employees entity bean on the diagram to open the source code for the class.

Add a comma at the end of the last @NamedQuery statement, then add the following statement:

@NamedQuery(name = "Employees.findByName",
query = "select o from Employees o where o.firstName like :p_name")

The code will look as follows:

@Entity
@NamedQueries({
@NamedQuery(name = "Employees.findAll", query = "select o from Employees o"),
@NamedQuery(name = "Employees.findByName", query = "select o from Employees o where o.firstName like :p_name")
})

Note:

What makes these objects different from other Java files are the annotations that identify them as EJB entities. A key feature of EJB 3.0 and JPA is the ability to create entities that contain object-relational mappings by using metadata annotations rather than deployment descriptors as in earlier versions.

Click the Make icon to compile the Employees.java class. Make sure that the Message - Log window does not report any errors.

Right-click the HRFacadeBean node in the Application Navigator and select Edit Session Facade from the context menu.

Expand the Employees node of the dialog. The new named query Employees.findByName appears as an exposable method. Select it and click OK. This will add the new method to the session bean.

7.3.4 Running the Java Service outside Java EE container

A persistence unit can be configured to run inside or outside the container. In this section, you create a session bean that implements a method to find employee and department records.

Expand META-INF then right-click the persistence.xml. Select New Java Service Facade from the context menu.

In the Java Service Class panel, you can choose to create a new persistence unit or use an existing unit. Select Choose a Persistence Unit or Create one in the next Panel, and check the Generate a main() method checkbox. Click Next.

Name the the Persistence Unit outside. Choose JDBC Connection and make sure the JDBC connection is set to HRConn. Click Next.

All methods should be selected by default. Deselect all the byRange methods. Click Next, then Finish.

Figure 7-3 Creating Java Service Facade

In the source editor window, for the JavaServiceFacade class, add a new line after the // TODO comment and enter the following statement:

Employees a = javaServiceFacade.queryEmployeesFindByName("P%").get(0);

Compile the class and save your work.

Right-click the JavaServiceFacade node in the Application Navigator and select Run from context.

The Log window displays the result of the execution of the class running outside Java EE container, returning the first lastName of the retrieved records.

Expand META-INF and double-click persistence.xml to display the contents of the file.

Both persistence units are described. The default inside one and the newly-created for outside Java EE run. Click the Source tab to review details.

You now expose the EJB as a data control for the Oracle ADF framework. This simplifies the way that you bind user interfaces to the EJB.

Right-click the HRFacadeBean node in the Application Navigator and select Create Data Controls from context.

In the Choose EJB Interface dialog, select Local, and click OK. Save all your work.

7.4 Create a New Project for the User Interface

The application user interface consists of a set of JSP pages. For this application, the user interface (UI), referred to as the view, is defined in a separate project.

To create the application UI, you define a project called UserInterface as follows:

In the Application Navigator, select the HR_EJB_JPA_App application and from the File menu, select New to display the New Gallery. From the General category, select Project. From the Items list, select Generic Project and click OK.

In the Create Generic Project screen, enter UserInterface as the Name of the new project, and click Finish.

In the Application Navigator, right click the UserInterface node and select Project Properties from context.

In the Project Properties dialog, select the JSP Tag Libraries node. Select Distributed libraries, then click Add.

In the Tag Libraries list, select ADF Faces Components 11. Click OK.

Select the Technology scope node. In the Available technologies list, select JSF. Notice that selecting JSF automatically propagates the required associated technologies, Java, JSP and Servlets. Click OK. Save your work.

7.5 Creating the Page Flow

You now use JDeveloper's JSF Navigation Modeler to diagrammatically plan and create your application's pages, and the navigation between them.

In the Application Navigator, expand UserInterface, then Web Content, and then WEB_INF. Double click faces-config.xml to open a page flow diagram.

In the JSF Navigation Diagram page of the Component Palette, select JSF Page, and click in the diagram where you want the page to appear. Rename the page browse.

From the Component Palette, drag and drop a JSF Page next to the previous one. Rename the page query.

Select JSF Navigation Case in the Component Palette. Click the icon for the source JSF page (browse), and then click the icon for the destination JSF page (query) for the navigation case.

Modify the default label, success, by clicking it and typing query over it. Notice that there is a warning icon above the Navigation Case. This is because you have not yet created the JSF pages.This warning disappears when you create the respective pages.

Select JSF Navigation Case in the Component Palette. Click the icon for the source JSF page (query), and then click the icon for the destination JSF page (browse) for the navigation case. Rename the label to browse. Save your work.

Figure 7-4 JSF Navigation

7.6 Creating a Master-Detail JavaServer Faces Page

In the next few steps, you create a JavaServer Faces Page using ADF Faces components for the Department Employees Master Detail page.

On the Page Flow diagram, double-click the browse icon to launch the Create JSF JSP wizard.

The File name should be browse.jspx, select the Create as XML Document option. Click OK.

You now have an empty browse.jspx page. In the next few steps, you add a data-bound ADF Faces component to the page. This component displays a department along with the employees belonging to this department.

From the Component palette, for the ADF Faces library, select the Layout section and drag a Panel Stretch Layout component onto the page

From the Component Palette, drag a Panel Splitter component on the middle of the page. The cursor should be on the left of the center tag.

Open the Data Controls component and expand HRFacadeLocal, then queryDepartmentsFindAll and then drag and drop the Departments node within the first facet. In the pop up menu, select Forms, then ADF Read-only Form.

In the Edit Form Fields, check the Include Navigation Controls option. Click OK.

In the Data Controls, expand the Departments node, select the employeesList node and drop it in the second facet. In the pop up menu, select Tables, then ADF Read-only Table.

In the Edit Table Columns dialog delete all columns except the following:

commissionPct

email

employeeId

firstName

hiredate

jobId

lastName

phoneNumber

salary

Select Row Selection, and Sorting options. Click OK.

In the Structure pane, select the af:panelSplitter pane and in the Property Inspector, set the Orientation to vertical.

Select the af:panelStretchLayout tag. In the Property Inspector, expand Style. In the Box tab set the Width to 600 Pixel and the Height to 400 Pixel so that the Employees table appears in the layout editor.

Select the af:table tag in the second pane. In the Property Inspector, expand Style. In the Box tab set the Width to 100 Pct and the Height to 100 Pct.

Reduce the height of the Department block on the page using your mouse to drag the line.

You want the employees section of this page to refresh when the user navigates between departments. You implement that by adding a Partial Page Rendering trigger to the employees table.

Select the First button and in the Properties Inspector add first as the ID. Repeat this for the remaining 3 buttons. Set Previous to previous, Next to next, and Last to last.

Set the Partial Page Rendereing trigger to fire when the user clicks any of those buttons.

Select the employees table. In the Properties Inspector, expand Behavior, then PartialTriggers property and click on Edit. The Edit button is on the far right of the field.

In the Edit Property dialog, expand facet (first), then panelFormLayout - Departments , then facet (footer), and then panelGroupLayout to expose the navigation buttons. Add all four buttons to the selected list. Click OK.

From the Component Palette, in the Common Components, select the Panel Menu Bar component and drop it onto the Facet Top tag, in the Design of the page. Click the Menu component then drag and drop it inside the Menu Bar.

(AFBrandingBarTitle, AFHeaderLevelTwo, Click Browse Employees and select Heading2. Drag to resige top facet)

In the Property Inspector change the Text from menu 1 to Options. Click the Behavior tab and set the Detachable field to true.

In the Structure Pane, right-click the af:menu tag and from context select Insert Inside af:menu and then MenuItem.

In the Property Inspector, using the Common tab, change the Text to Query and from the drop down list set the Action to query. Save your work.

7.7 Creating a Query and Edit Page

In the next few steps, you use ADF Faces to build the query page to edit Employees.

Click the faces-config.xml tab to switch back to the Page Flow diagram, and double-click the query icon to launch the page wizard.

The file name should be query.jspx and Create as XML Document is checked. Click OK

A new Design page opens. In Data Controls, under the HRFacadeLocal node, select the queryEmployeesFindByName(Object) node and drop it onto the page. From the popup menu, select Parameters, then ADF Parameter Form.

In the Edit Form Fields click OK to accept the proposed fields.

In the Edit Action Binding dialog click OK.

In the Data Controls, expand the queryEmployeesFindByName node and select the Employees node. Drop it onto the page below the Parameter Form. From the popup menu, select Forms, then ADF Form.

In the Edit Form Fields, select Include Navigation Controls and Include Submit Button checkboxes. Click OK.

This page needs to be updatable. To specify this, select the mergeEntity(Object) method in the Data Controls pane, and drop it onto the Submit button. In the Edit Action Binding dialog, click the down arrow and select Show EL Expression Builder.

In the Variables dialog, expand ADF Bindings, then Bindings, then queryEmployeesFindByNameIterator, then currentRow and select dataProvider. As you select each node in the expression. the editor adds it to the expression in the top of the window.

Click OK. Click OK again. In the Confirm Component Rebinding dialog, click OK.

In the design of the query page, select the mergeEntity button

In the Property Inspector, Common tab, set the Text value to Save and in the Button Action section, set the the Action to browse from the drop down list. Save your work.

7.8 Running the Application

You may now run the application as follows:

In the Application Navigator, right-click browse.jsp and select Run from the shortcut menu.

As you run the application, you will be able to navigate through the different Departments and then select individual Employees for editing. Experiment with updating either the salary or hiredate of an employee.

The Employees page displayed in a browser is shown in Figure 7-5.

Figure 7-5 Master-Detail Application Viewed in a Browser

The edit page displayed in a browser is similar to that shown in Figure 7-6.

Figure 7-6 Editing the Master Detail Application Content

8 Getting Unconnected from Oracle Database

While unconnecting from the database in JDeveloper is a simple task, it is not a process by itself in a Java application. In the application, you must explicitly close all ResultSet, Statement, and Connection objects after you are through using them. When you close the Connection object, you are unconnected from the database. The close methods clean up memory and release database cursors. Therefore, if you do not explicitly close ResultSet and Statement objects, serious memory leaks may occur, and you may run out of cursors in the database. You must then close the connection.

This chapter includes the following sections:

Creating a Method to Close All Open Objects

Closing Open Objects in the Application

8.1 Creating a Method to Close All Open Objects

The following steps add a closeAll method to the DataHandler class:

Open DataHandler.java in the Java Source Editor by double-clicking it in the Application Navigator.

Declare the closeAll method at the end of the DataHandler class as follows:

public void closeAll() {

}

Within the method body, check whether the ResultSet object is open as follows:

if ( rset != null ) {

If it is open, close it and handle any exceptions as follows:

  try { rset.close(); } catch ( Exception ex ) {}
  rset = null;
}

Repeat the same actions with the Statement object.

if ( stmt != null ) {
  try { stmt.close(); } catch ( Exception ex ) {}
  stmt = null;
}

Finally, close the Connection object.

if ( conn != null ) {
  try { conn.close(); } catch ( Exception ex ) {}
  conn = null;
}

8.2 Closing Open Objects in the Application

You must close the ResultSet, Statement, and Connection objects only after you have finished using them. In the DataHandler class, the insert, update, and delete methods must close these objects before returning. Note that the query methods cannot close these objects until the employees.jsp page has finished processing the rows returned by the query.

In the following steps, you add the appropriate calls to the closeAll method in the DataHandler.java file:

Open DataHandler.java in the Java Source Editor.

At the end of the addEmployee method, after the closing brace of the catch block, add the following call to the closeAll method in a finally block:

finally {
  closeAll();
}

Add the same call to the addEmployeeSP, deleteEmployeeById, findEmployeeById, updateEmployee, and authenticateUser methods.

Open the employees.jsp file in the Visual Editor. Find the scriptlet inside the Employees table, and double-click to open the Insert Scriptlet dialog box.

Add the following statement after the while loop:

empsbean.closeAll();

Save your work, and compile and run the application to ensure that everything still works correctly.

9 Building Global Applications

Building a global Internet application that supports different locales requires good development practices. A locale refers to a national language and the region in which the language is spoken. The application itself must be aware of user locale preferences and present content following the cultural convention expected by the user. It is important to present data with appropriate locale characteristics, such as using the correct date and number formats. Oracle Database is fully internationalized to provide a global platform for developing and deploying global applications.

This chapter discusses global application development in a Java and Oracle Database environment. It addresses the basic tasks associated with developing and deploying global Internet applications, including developing locale awareness, constructing HTML content in the user-preferred language, and presenting data following the cultural conventions of the user locale.

This chapter has the following topics:

Developing Locale Awareness

Determining User Locales

Encoding HTML Pages

Organizing the Content of HTML Pages for Translation

Presenting Data by User Locale Convention

Localizing Text on JSP Pages in JDeveloper

9.1 Developing Locale Awareness

Global Internet applications must be aware of the user locale. Locale-sensitive functions, such as date, time, and monetary formatting, are built into programming environments such as Java and SQL. Applications can use locale-sensitive functions to format the HTML pages according to the cultural conventions of the user locale.

Different programming environments represent locales in different ways. For example, the French (Canadian) locale is represented as follows:

Environment
Representation
Locale
Explanation

Java
Java locale object
fr_CA
Java uses the ISO language and country code.

fr is the language code defined in the ISO 639 standard. CA is the country code defined in the ISO 3166 standard.

SQL and PL/SQL
NLS_LANGUAGE and NLS_TERRITORY parameters
NLS_LANGUAGE ="CANADIAN FRENCH"

NLS_TERRITORY ="CANADA"

See also: Chapter 8 "Working in a Global Environment" in the Oracle Database Express Edition 2 Day Developer Guide.

Table 9-1 shows how some of the commonly used locales are defined in Java and Oracle environments.

Table 9-1 Locale Representation in Java, SQL, and PL/SQL Programming Environments

Locale
Java
NLS_LANGUAGE, NLS_TERRITORY

Chinese (P.R.C)

zh_CN

SIMPLIFIED CHINESE, CHINA

Chinese (Taiwan)

zh_TW

TRADITIONAL CHINESE, TAIWAN

English (U.S.A)

en_US

AMERICAN, AMERICA

English (United Kingdom)

en_GB

ENGLISH, UNITED KINGDOM

French (Canada)

fr_CA

CANADIAN FRENCH, CANADA

French (France)

fr_FR

FRENCH, FRANCE

German (Germany)

de_DE

GERMAN, GERMANY

Italian (Italy)

it_IT

ITALIAN, ITALY

Japanese (Japan)

ja_JP

JAPANESE, JAPAN

Korean (Korea)

ko_KR

KOREAN, KOREA

Portuguese (Brazil)

pt_BR

BRAZILIAN PORTUGUESE, BRAZIL

Portuguese (Portugal)

pt_PT

PORTUGUESE, PORTUGAL

Spanish (Spain)

es_ES

SPANISH, SPAIN

When writing global applications across different programming environments, the user locale settings must be synchronized between environments. For example, Java applications that call PL/SQL procedures should map the Java locales to the corresponding NLS_LANGUAGE and NLS_TERRITORY values and change the parameter values to match the user locale before calling the PL/SQL procedures.

9.1.1 Mapping Between Oracle and Java Locales

The Oracle Globalization Development Kit (GDK) provides the LocaleMapper class. It maps equivalent locales and character sets between Java, IANA, ISO, and Oracle. A Java application may receive locale information from the client that is specified in the Oracle locale name. The Java application must be able to map to an equivalent Java locale before it can process the information correctly.

Example 9-1 shows how to use the LocaleMapper class.

Example 9-1 Mapping from a Java Locale to an Oracle Language and Territory

Locale locale = new Locale("fr", "CA");
String oraLang = LocaleMapper.getOraLanguage(locale);
String oraTerr = LocaleMapper.getOraTerritory(locale);

The GDK is a set of Java application programming interfaces (APIs) that provide Oracle application developers with the framework to develop globalized Internet applications. The GDK complements the existing globalization features in Java. It provides the synchronization of locale behaviors between a middle-tier Java application and the Oracle database server.

9.2 Determining User Locales

In a global environment, your application may have to accept users with different locale preferences. Determine the preferred locale of the user. Once that is known, the application should construct HTML content in the language of the locale, and follow the cultural conventions implied by the locale.

One of the most common methods in determining the user locale, is based on the default ISO locale setting of the browser of the user. Usually a browser sends locale preference settings to the HTTP server with the Accept-Language HTTP header. If this header is set to NULL, then there is no locale preference information available and the application should ideally fall back to a predefined application default locale.

Both JSP pages and Java Servlets can use calls to the Servlet API to retrieve the Accept-Language HTTP header as shown in Example 9-2.

Example 9-2 Determining User Locale in Java Using the Accept-Language Header

String lang = request.getHeader("Accept-Language")
StringTokenizer st = new StringTokenizer(lang, ",")
if (st.hasMoreTokens()) userLocale = st.nextToken();

This code gets the Accept-Language header from the HTTP request, extracts the first ISO locale, and uses it as the user-desired locale.

9.2.1 Locale Awareness in Java Applications

A Java locale object represents the locale of the corresponding user in Java. The Java encoding used for the locale is required to properly convert Java strings to and from byte data. You must consider the Java encoding for the locale if you make the Java code aware of a user locale. There are two ways to make a Java method sensitive to the Java locale and encoding:

Using the default Java locale and default Java encoding for the method

Explicitly specifying the Java locale and Java encoding for the method

When developing a global application, it is recommended to take the second approach and explicitly specify the Java locale and Java encoding that correspond to the current user locale. You can specify the Java locale object that corresponds to the user locale, identified by user_locale, in the getDateTimeInstance method as in Example 9-3.

Example 9-3 Explicitly Specifying User Locale in Java

DateFormat df = DateFormat.getDateTimeInstance(DateFormat.FULL, DateFormat.FULL, user_locale);
dateString = df.format(date); /* Format a date */

9.3 Encoding HTML Pages

The encoding of an HTML page is important information for a browser and an Internet application. You can think of the page encoding as the character set used for the locale that an Internet application is serving. The browser needs to know about the page encoding so that it can use the correct fonts and character set mapping tables to display the HTML pages. Internet applications need to know about the HTML page encoding so they can process input data from an HTML form.

Instead of using different native encodings for the different locales, it is recommended that UTF-8 (Unicode encoding) is used for all page encodings. Using the UTF-8 encoding not only simplifies the coding for global applications, but it allows for multilingual content on a single page.

This section includes the following topics:

Specifying the Page Encoding for HTML Pages

Specifying the Page Encoding in Java Servlets and JSP Pages

9.3.1 Specifying the Page Encoding for HTML Pages

There are two ways to specify the encoding of an HTML page, one is in the HTTP header, and the other is in the HTML page header.

Specifying the Encoding in the HTTP Header

Include the Content-Type HTTP header in the HTTP specification. It specifies the content type and character set as shown in Example 9-4.

Example 9-4 Specifying Page Encoding in the HTTP Specification

Content-Type: text/html; charset=utf-8

The charset parameter specifies the encoding for the HTML page. The possible values for the charset parameter are the IANA names for the character encodings that the browser supports.

Specifying the Encoding in the HTML Page Header

Use this method primarily for static HTML pages. Specify the character encoding in the HTML header as shown in Example 9-5.

Example 9-5 Specifying Page Encoding on an HTML Page

<meta http-equiv="Content-Type" content="text/html;charset=utf-8">

The charset parameter specifies the encoding for the HTML page. As with the Content-Type HTTP Header, the possible values for the charset parameter are the IANA names for the character encodings that the browser supports.

9.3.2 Specifying the Page Encoding in Java Servlets and JSP Pages

You can specify the encoding of an HTML page in the Content-Type HTTP header in a JavaServer Pages (JSP) file using the contentType page directive. For example:

<%@ page contentType="text/html; charset=utf-8" %>

This is the MIME type and character encoding that the JSP file uses for the response it sends to the client. You can use any MIME type or IANA character set name that is valid for the JSP container. The default MIME type is text/html, and the default character set is ISO-8859-1. In the above example, the character set is set to UTF-8. The character set of the contentType page directive directs the JSP engine to encode the dynamic HTML page and set the HTTP Content-Type header with the specified character set.

For Java Servlets, you can call the setContentType method of the Servlet API to specify a page encoding in the HTTP header. The doGet function in Example 9-6 shows how you can call this method.

Example 9-6 Specifying Page Encoding in Servlets Using setContentType

public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException
{

// generate the MIME type and character set header
response.setContentType("text/html; charset=utf-8");

...

// generate the HTML page
Printwriter out = response.getWriter();
out.println("<HTML>");

...

out.println("</HTML>");
}

You should call the setContentType method before the getWriter method because the getWriter method initializes an output stream writer that uses the character set specified by the setContentType method call. Any HTML content written to the writer and eventually to a browser is encoded in the encoding specified by the setContentType call.

9.4 Organizing the Content of HTML Pages for Translation

Making the user interface available in the local language of the user is one of the fundamental tasks related to globalizing an application. Translatable sources for the content of an HTML page belong to the following categories:

Text strings hard-coded in the application code

Static HTML files, images files, and template files such as CSS

Dynamic data stored in the database

This section discusses externalizing translatable content in the following:

Strings in Java Servlets and JSP Pages

Static Files

Data from the Database

9.4.1 Strings in Java Servlets and JSP Pages

You should externalize translatable strings within Java Servlets and JSP pages into Java resource bundles so that these resource bundles can be translated independent of the Java code. After translation, the resource bundles carry the same base class names as the English bundles, but with the Java locale name as the suffix. You should place the bundles in the same directory as the English resource bundles for the Java resource bundle look-up mechanism to function properly.

See Also:

Sun Microsystems documentation about Java resource bundles at

http://java.sun.com/j2se/1.4.2/docs/api/java/util/ResourceBundle.html

Because the user locale is not fixed in multilingual applications, they should call the getBundle method by explicitly specifying a Java locale object that corresponds to the user locale. The Java locale object is called user_locale in the following example:

ResourceBundle rb = ResourceBundle.getBundle("resource", user_locale);
String helloStr = rb.getString("hello");

The above code will retrieve the localized version of the text string, hello, from the resource bundle corresponding to the desired locale of the user.

See Also:

For more information on creating resource bundles in Java, refer to Localizing Text on JSP Pages in JDeveloper.

9.4.2 Static Files

Static files such as HTMLs and GIFs are readily translatable. When these files are translated, they should be translated into the corresponding language with UTF-8 as the file encoding. To differentiate between the languages of the translated files, the static files of different languages can be staged in different directories or with different file names.

9.4.3 Data from the Database

Dynamic information such as product names and product descriptions are most likely stored in the database regardless of whether you use JSP pages or Java Servlets. In order to differentiate between various translations, the database schema holding this information should include a column to indicate the language of the information. To select the translated information, you must include the WHERE clause in your query to select the information in the desired language of the query.

9.5 Presenting Data by User Locale Convention

Data in the application needs to be presented in a way that conforms to user expectation, if not, the meaning of the data can sometimes be misinterpreted. For example, '12/11/05' implies '11th December 2005' in the United States, whereas in the United Kingdom it means '12th November 2005'. Similar confusion exists for number and monetary formats, for example, the period (.) is a decimal separator in the United States, whereas in Germany, it is used as a thousand separator.

Different languages have their own sorting rules, some languages are collated according to the letter sequence in the alphabet, some according to stroke count in the letter, and there are some languages which are ordered by the pronunciation of the words. Presenting data that is not sorted according to the linguistic sequence that your users are accustomed to can make searching for information difficult and time-consuming.

Depending on the application logic and the volume of data retrieved from the database, it may be more appropriate to format the data at the database level rather than at the application level. Oracle Database offers many features that help you to refine the presentation of data when the user locale preference is known. The following sections include examples of locale-sensitive operations in SQL:

Oracle Date Formats

Oracle Number Formats

Oracle Linguistic Sorts

Oracle Error Messages

9.5.1 Oracle Date Formats

There are three different date presentation formats in Oracle Database. These are standard, short, and long dates. Example 9-7 illustrates the difference between the short data and long date formats for both United States and Germany.

Example 9-7 Difference Between Date Formats by Locale (United States and Germany)

SQL> ALTER SESSION SET NLS_TERRITORY=america NLS_LANGUAGE=american;

Session altered.

SQL> SELECT employee_id EmpID,
  2  SUBSTR(first_name,1,1)||'.'||last_name "EmpName",
  3  TO_CHAR(hire_date,'DS') "Hiredate",
  4  TO_CHAR(hire_date,'DL') "Long HireDate"
  5  FROM employees
  6* WHERE employee_id <105;

     EMPID EmpName                     Hiredate   Long HireDate
---------- --------------------------- ---------- -----------------------------
       100 S.King                      06/17/1987 Wednesday, June 17, 1987
       101 N.Kochhar                   09/21/1989 Thursday, September 21, 1989
       102 L.De Haan                   01/13/1993 Wednesday, January 13, 1993
       103 A.Hunold                    01/03/1990 Wednesday, January 3, 1990
       104 B.Ernst                     05/21/1991 Tuesday, May 21, 1991

SQL> ALTER SESSION SET SET NLS_TERRITORY=germany NLS_LANGUAGE=german;

Session altered.

SQL> SELECT employee_id EmpID,
  2  SUBSTR(first_name,1,1)||'.'||last_name "EmpName",
  3  TO_CHAR(hire_date,'DS') "Hiredate",
  4  TO_CHAR(hire_date,'DL') "Long HireDate"
  5  FROM employees
  6* WHERE employee_id <105;

     EMPID EmpName                     Hiredate Long HireDate
---------- --------------------------- -------- ------------------------------
       100 S.King                      17.06.87 Mittwoch, 17. Juni 1987
       101 N.Kochhar                   21.09.89 Donnerstag, 21. September 1989
       102 L.De Haan                   13.01.93 Mittwoch, 13. Januar 1993
       103 A.Hunold                    03.01.90 Mittwoch, 3. Januar 1990
       104 B.Ernst                     21.05.91 Dienstag, 21. Mai 1991

9.5.2 Oracle Number Formats

Example 9-8 illustrates the differences in the decimal character and group separator between the United States and Germany.

Example 9-8 Difference Between Number Formats by Locale (United States and Germany)

SQL> ALTER SESSION SET SET NLS_TERRITORY=america;

Session altered.

SQL> SELECT employee_id EmpID,
  2  SUBSTR(first_name,1,1)||'.'||last_name "EmpName",
  3  TO_CHAR(salary, '99G999D99') "Salary"
  4  FROM employees
  5* WHERE employee_id <105

     EMPID EmpName                     Salary
---------- --------------------------- ----------
       100 S.King                       24,000.00
       101 N.Kochhar                    17,000.00
       102 L.De Haan                    17,000.00
       103 A.Hunold                      9,000.00
       104 B.Ernst                       6,000.00

SQL> ALTER SESSION SET SET NLS_TERRITORY=germany;

Session altered.

SQL> SELECT employee_id EmpID,
  2  SUBSTR(first_name,1,1)||'.'||last_name "EmpName",
  3  TO_CHAR(salary, '99G999D99') "Salary"
  4  FROM employees
  5* WHERE employee_id <105

     EMPID EmpName                     Salary
---------- --------------------------- ----------
       100 S.King                       24.000,00
       101 N.Kochhar                    17.000,00
       102 L.De Haan                    17.000,00
       103 A.Hunold                      9.000,00
       104 B.Ernst                       6.000,00

9.5.3 Oracle Linguistic Sorts

Spain traditionally treats 'ch', 'll' as well as 'ñ' as letters of their own, ordered after c, l and n respectively. Example 9-9 illustrates the effect of using a Spanish sort against the employee names Chen and Chung.

Example 9-9 Variations in Linguistic Sorting (Binary and Spanish)

SQL> ALTER SESSION SET NLS_SORT=binary;

Session altered.

SQL> SELECT employee_id EmpID,
  2         last_name "Last Name"
  3  FROM employees
  4  WHERE last_name LIKE 'C%'
  5* ORDER BY last_name

     EMPID Last Name
---------- -------------------------
       187 Cabrio
       148 Cambrault
       154 Cambrault
       110 Chen
       188 Chung
       119 Colmenares

6 rows selected.

SQL> ALTER SESSION SET NLS_SORT=spanish_m;

Session altered.

SQL> SELECT employee_id EmpID,
  2         last_name "Last Name"
  3  FROM employees
  4  WHERE last_name LIKE 'C%'
  5* ORDER BY last_name

     EMPID Last Name
---------- -------------------------
       187 Cabrio
       148 Cambrault
       154 Cambrault
       119 Colmenares
       110 Chen
       188 Chung

6 rows selected.

9.5.4 Oracle Error Messages

The NLS_LANGUAGE parameter also controls the language of the database error messages that are returned from the database. Setting this parameter prior to submitting your SQL statement will ensure that local language-specific database error messages will be returned to the application.

Consider the following server message:

ORA-00942: table or view does not exist

When the NLS_LANGUAGE parameter is set to French, the server message appears as follows:

ORA-00942: table ou vue inexistante

See Also:

"Working in a Global Environment" chapter in the Oracle Database Express Edition 2 Day DBA for a discussion of globalization support features within Oracle Database.

9.6 Localizing Text on JSP Pages in JDeveloper

Your Java application can make use of resource bundles, to provide different localized versions of the text used on your JSP pages.

Resource bundles contain locale-specific objects. When your program needs a locale-specific resource, such as some text to display on a page, your program can load it from the resource bundle that is appropriate for the current user locale. In this way, you can write program code that is largely independent of the user locale isolating the actual text in resource bundles.

In outline, the resource bundle technology has the following features:

Resource bundles belong to families whose members share a common base name, but whose names also have additional components that identify their locales. For example, the base name of a family of resource bundles might be MyResources. A locale-specific version for German, for example, would be called MyResources_de.

Each resource bundle in a family contains the same items, but the items have been translated for the locale represented by that resource bundle. For example, a String used on a button might in MyResources be defined as Cancel, but in MyResources_de as Abbrechen.

You can make specializations for different resources for different countries, for example, for the German language (de) in Switzerland (CH).

To use resource bundles in your application, you must do the following:

Create the resource bundles.

In pages that have visual components, identify the resource bundles you will be using on the page.

For each item of text you want to display on your pages, retrieve the text from the resource bundle instead of using hard-coded text.

See Also:

Sun Microsystems documentation on resource bundles at

http://java.sun.com/j2se/1.4.2/docs/api/java/util/ResourceBundle.html

In the sample application, resource bundles can be used in the following places:

Headings and labels on JSP pages. In this case, rather than entering text directly on the pages, you can use a scriptlet to find the text.

Values for buttons and other controls. In this case, set the value property of the button to an expression that retrieves the text from the resource bundle

This section covers the following tasks:

Creating a Resource Bundle

Using Resource Bundle Text on JSP Pages

9.6.1 Creating a Resource Bundle

To create a default resource bundle:

Create a new Java class called MyResources.java, that extends class java.util.ListResourceBundle.

Define the resource bundle class and methods to return contents as follows:

public class MyResources extends ListResourceBundle
{
  public Object[][] getContents() {
    return contents;
  }
  static final Object[][] contents = {
  };
}

Add an entry for each item of text you need on your pages, giving a key and the text for that key. For example, in the following example, the comments indicate the strings that must be translated into other languages:

  static final Object[][] contents = {
    // LOCALIZE THIS
    {"CompanyName", "AnyCo Corporation"},
    {"SiteName", "HR Application"},
    {"FilterButton", "Filter"},
    {"UpdateButton", "Update"},
    // END OF MATERIAL TO LOCALIZE
  };

The complete resource bundle class should look similar to that shown in Example 9-10.

Example 9-10 Creating a Resource Bundle Class

public class MyResources extends ListResourceBundle
{
  public Object[][] getContents() {
    return contents;
  }
  static final Object[][] contents = {
    // LOCALIZE THIS
    {"CompanyName", "AnyCo Corporation"},
    {"SiteName", "HR Application"},
    {"FilterButton", "Filter"},
    {"UpdateButton", "Update"},
    // END OF MATERIAL TO LOCALIZE
  };
}

To globalize your application, you must create the locale-specific versions of the resource bundle for the different locales you are supporting, containing text for the items in each language.

9.6.2 Using Resource Bundle Text on JSP Pages

To use the text defined in a resource bundle on your JSP pages:

Open the JSP page you want to work on in the Visual Editor, such as edit.jsp.

Create a new line at the top of the page before the first heading and set the Style of the line to None. Add a jsp:usebean tag to the new line. Enter myResources as the ID, and hr.MyResources as the Class. Set the Scope to session, and click OK.

Drag a jsp:scriptlet to the page, where you want the resource bundle text to be displayed, for example in the heading for the page.

In the Insert Scriptlet dialog, enter the script for retrieving text from the resource bundle:

  out.println(myResources.getString("CompanyName") + ": " +
  myResources.getString("SiteName"));

If there was text already displayed in the heading, you can remove it now.

If you select the Source tab below the Visual Editor, you should see code for the page similar to the following:

<h2 align="center">
  <% = myResources.getString("CompanyName") + ": " +
              myResources.getString("SiteName"));
  %>
</h2>

To use resource bundle text as the label for a button, double-click the button in the Visual Editor. In the button properties dialog, for the Value parameter of the button, enter a script similar to the following:

<% out.println(myResources.getString("UpdateButton"));%>

If you view the Source code for the page, you will see code similar to the following:

<input type="submit"
  value=<% out.println(myResources.getString("UpdateButton"));%> />

If you now run your application, you will see the text you defined in your resource bundle displayed on the page.

Index

A  B  C  D  E  F  G  H  I  J  L  M  N  O  P  Q  R  S  T  U  V  W  X 

A

absolute positioning in result sets, 4.1.3.1

accessor methods, 5.1.2

ADF Data Controls, 7.2.3

Apache Tomcat, 2.1.5

application navigation, 5.6

HTML submit buttons, 5.6

jsp

forward tags, 5.6

Application Navigator, 3.2.1

using, 3.2.1

application UI, 7.4

application, creating, 7.3.1

B

bind variables, 6.1.1

IN, OUT, and IN OUTparameters, 6.1.3

OracleCallableStatement, 6.1.3

OraclePreparedStatement, 6.1.3

using, 6.1.3

C

CLASSPATH, 2.2.2

CLI, 1

closing objects

application, 8.2

closeAll method, 8.1, 8.1, 8.2

Connection, 8.1

DataHandler, 8.1

DataHandler.java, 8.2

employees.jsp, 8.2

ResultSet, 8.1

Statement, 8.1

Component Palette, 1.2.2

connecting from JDeveloper

driver, specifying, 3.1.2

host name, specifying, 3.1.2

JDBC port, specifying, 3.1.2

service name, specifying, 3.1.2

connecting to Oracle Database

DataSource object, 3.3.1

default service, 3.3.2.1

getDBConnection, 3.3.1

overview of, 3.3.1

using Java, 3.3, 3.3.1

using JDeveloper, 1.2

Connection object, 7.3.1

DataSource, 3.3.1

DriverManager, 3.3.1

CSS

list of components, 4.3.4

cursor variables

REF CURSOR, 6.3

using, 6.3

D

Database Navigator, 3.1.2

browsing data, 3.1.3

database objects, editing, 3.1.3

table data, viewing, 3.1.3

table definition, viewing, 3.1.3

database URLs, 3.3.2

database_specifier, 3.3.2

driver_type, 3.3.2

syntax, 3.3.2

thin-style service names, 3.3.2

DataHandler.java, 1.3, 4.2.1

DataSource object, 3.3.1

databaseName, 3.3.1

dataSourceName, 3.3.1

description, 3.3.1

driverType, 3.3.1

networkProtocol, 3.3.1

password, 3.3.1

portNumber, 3.3.1

properties, 3.3.1

serverName, 3.3.1

url, 3.3.1

user, 3.3.1

Datasource object

properties, 3.3.1

url property, 3.3.1

deafault service

URLs, examples, 3.3.2.1

default service

syntax, 3.3.2.1

using, 3.3.2.1

delete_action.jsp, 1.3

deleting data, 5.4

creating a method, 5.4.1

DataHandler.java, 5.4.1

delete_action.jsp, 5.4.2, 5.4.3

handling a delete action, 5.4.3

link to delete, 5.4.2

deployment descriptor file, 5.6

dynamic SQL

OracleCallableStatement, 6.1

OraclePreparedStatement, 4.1.1, 6.1

using, 6.1

E

edit.jsp, 1.3

Employees.java, 1.3

employees.jsp, 1.3, 4.3.3

Entry Level of the SQL-92, 1

environment variables

specifying, 2.2.2

environment variables, checking, 2.2.2

exception handling, 5.5

catch block, 5.5, 5.5.1

DataHandler.java, 5.5.2

deleteEmployee, 5.5.1

getAllEmployees, 5.5

handling any SQLException, 5.5.2

SQLException, 5.5

try block, 5.5, 5.5.1

execute, 4.1.2

executeBatch, 4.1.2

executeQuery, 4.1.2

executeUpdate, 4.1.2

F

filtering data, 4.5

DataHandler.java, 4.5.1

G

getAllEmployees, 4.4.2

getCursor method, 6.3.2

getDBConnection method, 4.2.1

globalization classes file, 2.2.2

H

HR account

testing, 2.1.1.1

HR user account

sample application, 2.1.1.1

unlocking, 2.1.1.1

HTML forms, 4.3.1.4

HTML tags, 4.3.1.3

I

IBM WebSphere, 2.1.5

IDE, 1.2.1, 2.1.4

Oracle JDeveloper, 2.1.4

importing packages

import dialog box, 4.4.2

IN parameters, 6.1.2

index.jsp, 1.3

index.jsp, creating, 5.6.1

insert_action.jsp, 1.3

inserting data, 5.3

employees.jsp, 5.3.4

handle an insert action, 5.3.4

insert_action.jsp, 5.3.3, 5.3.4

insert.jsp, 5.3.3

JSP, 5.3.3

link to insert page, 5.3.2

method, creating, 5.3.1

new data, entering, 5.3.3

insert.jsp, 1.3

installation

directories and files, 2.2.1

verifying on the client, 2.2

integrated development environment, 2.1.4

InternetworkPacket Exchange

Oracle JDBC OCI Driver, 1.1.2

IPX, 1.1.2

J

J2SE, 2.1.3

installing, 2.1.3

Java Runtime Environment, 2.1.3

JDBC API, 2.1.3

Java class, 3.3.3

creating, 3.3.3

DataHandler, 3.3.3

Java Database Connectivity, 1

Java libraries

adding in JDeveloper, 3.3.4

JSP runtime library, 3.3.4.2

Oracle JDBC library, 3.3.4.1

Java Persistence API, 7.2.1

Java Visual Editor, 1.2.2

JavaBean, 5.1

Create Bean dialog box, 5.1.1

creating, 5.1

creating in JDeveloper, 5.1.1

defining, 5.1.2

Employee.java, 5.1.1

Employees table, 5.1.2

properties and methods, creating, 5.1.2

sample application, 5.1

JavaClient.java, 1.3

JavaServer Faces, 7.2.2

JavaServer Pages, 2.1.5

java.sql, 1, 1.1.3

JBoss, 2.1.5

JDBC, 1, 1.1

JDBC drivers

driver version, determining, 2.2.3

JDBC escape syntax, 6.2

JDBC Thin, 1.1

JDeveloper, 1.2, 1.2

Apache Tomcat, support for, 2.1.5

API support, 3.3.4

application templates, 3.2

application, creating, 3.2.2

applications, 3.2

base installation, 2.3.1

browsing data, 3.1.3

Component Palette, 1.2.2

Create Bean dialog box, 5.1.1

creating a Java Class, 3.3.3

database, connecting, 3.1, 3.1.2

database, disconnecting, 3.1.2

database, reconnecting, 3.1.2

default layout, 1.2.1

downloading, 2.3.2

full installation, 2.3.1

IBM WebSphere, support for, 2.1.5

installation guide, 2.3

installation requirements, 2.3.2

Java Code Insight, 1.2.2

Java Source Editor, 1.2.2

Java Visual Editor, 1.2.2

JavaBean, 5.1.1

JBoss, support for, 2.1.5

JDeveloper Database Navigator, 3.1.1

look and feel, 4.3.4

navigators, 1.2.1

online documentation, 2.3

Oracle Application Server, support for, 2.1.5

Oracle Java Virtual Machine, 2.3.1

Oracle WebLogic Server, support for, 2.1.5

platform support, 2.3

project, creating, 3.2.2

projects, 3.2

Property Inspector, 1.2.2

ResultSet object, creating, 4.4.2

scriptlet representation, 4.4.2

server support, 2.1.5

starting, 2.3.3

tools, 1.2.2

user interface, 1.2.1, 1.2.1

windows, 1.2.1, 1.2.1

JDeveloper Database Navigator, 3.1.1

browsing connections, 3.1.1

viewing database objects, 3.1.1

JDK 1.4, support, 2.1.3

JSP, 2.1.5

jsp

useBean tag, 4.4.1

JSP pages

creating, 4.3, 4.3.2

custom tag libraries, 4.3

deploying, 2.1.5

elements used, 4.3.1

handling login action, 4.6.5

HTML forms, 4.3.1.4

HTML tags, 4.3, 4.3.1.3

Java-based scriptlets, 4.3

JSP tags, 4.3

presentation, 4.3.1

scriptlets, 4.3.1.2

Standard JSP tags, 4.3

static content, adding, 4.3.3

style sheet, adding, 4.3.4

updating data, 5.2.4

JSP tags, 4.3, 4.3.1.1, 4.3.1.1

JSR 127 specification, 7.2.2

L

libraries

adding, 3.3.5

Project Properties dialog box, 3.3.5

login_action.jsp, 1.3

login.jsp, 1.3

M

master-detail application

files, 7.1

overview, 7.1

projects, 7.1

running, 7.8

model project, 7.3.2

Model-View-Controller design pattern, 7.1

MVC design pattern, 7.1

N

next method, 4.1.3

O

OCI, 1.1, 1.1.2

ODP.NET, 2.1.2

ojdbc5.jar, 2.2.2

OJVM, 2.3.1

Oracle ADF, 7, 7.2

service-oriented applications, creating, 7.2

Oracle ADF Business Components

features, 7.2.1

Oracle ADF Faces, 7.2.2

Oracle Application Developer Framework, 7

Oracle Application Development Framework, 7.2

Oracle Application Server, 2.1.5

Oracle Call Interface, 1.1

Oracle Data Provider for .NET, 2.1.2

Oracle Database

classes12*.* support, 2.1.3

client-side application development, 1.1

closing objects, 8

connecting to, 1.1

JDK 1.2 support, 2.1.3

JDK 1.3, 2.1.3

ojdbc5.jar file, using, 2.1.3

ojdbc6.jar file, using, 2.1.3

OracleConnectionCacheImpl, 2.1.3

oracle.jdbc.driver.* support, 2.1.3

unconnecting, 8

Oracle Database Client, 2.1.2, 3.3.2.1

development tools, 2.1.2

installation, 2.1.1, 2.1.2, 2.2

Oracle JDBC drivers, 2.1.2

Oracle ODBC Driver, 2.1.2

Oracle Provider for OLE DB, 2.1.2

Oracle Services for Microsoft Transaction Server, 2.1.2

verifying installation, 2.2

Oracle Database client

verifying, 2.2

Oracle Database Client installation

environment variables, 2.2.1

installed directories and files, 2.2.1

ORACLE_HOME /jlib, 2.2.1

ORACLE_HOME/jdbc, 2.2.1

platform-specific, 2.2

Oracle Database Server, 2.1.1

installation, 2.1.1

platform-specific, 2.1.1

Oracle Java Virtual Machine, 2.3.1

Oracle JDBC drivers, 2.1.2

Oracle JDBC library

oracle.jdbc, 3.3.4.1

oracle.jdbc.pool, 3.3.4.1

oracle.sql, 3.3.4.1

Oracle JDBC OCI Driver, 1.1.2

client installation, 1.1.2

Oracle JDBC Packages, 1.1.3

Oracle JDBC packages

oracle.jdbc, 1.1.3

oracle.sql, 1.1.3

Oracle JDBC support, 1.1

Oracle JDBC Thin Driver, 1.1.1

network protocols, 1.1.1

SQL*Net, 1.1.1

TCP/IP, 1.1.1

TTC protocol, 1.1.1

Type IV, 1.1.1

Oracle JDeveloper, 1.2

installing, 2.3

Oracle JDeveloper Studio Edition, 2.3

Oracle ODBC Driver, 2.1.2

Oracle Provider for OLE DB, 2.1.2

Oracle REF CURSOR Type, 6.3.1

Oracle Services for Microsoft Transaction Server, 2.1.2

Oracle WebLogic Server, 2.1.5

Oracle Weblogic Server, 3.3.4.2

ORACLE_HOME directory, 2.2.1

OracleCallableStatement, 6.1, 6.1.2

creating, 6.1.2

IN, OUT, IN OUT parameters, 6.1.2

using, 6.1.2

OracleDatabaseMetaData, 2.2.3

oracle.jdbc, 1.1, 1.1.3, 1.1.3, 3.3.4.1

java.sql, 1.1.3

Oracle JDBC library, 3.3.4.1, 3.3.4.1

oracle.jdbc.pool, 3.3.4.1

OraclePreparedStatement, 4.1.1, 6.1

bind variables, 6.1.1

creating, 6.1.1

precompiled, 6.1.1

using, 6.1.1

oracle.sql, 1.1, 1.1.3

data types, 1.1.3

Oracle JDBC library, 3.3.4.1

UCS-2 character set, 1.1.3

oracle.sql.Datum, 1.1.3

OracleTypes.CURSOR variable, 6.3.2

orai18n.jar, 2.2.2

P

positioning in result sets, 4.1.3.1

Project Properties dialog box, 3.3.5

projects, creating, 7.3.1

Property Inspector, 1.2.2

Q

querying data, 4.1, 4.1

DataHandler.java, 4.2.1

Java application, 4.2

JDBC concepts, 4.1

Log window output, 4.2.2

output, 4.2.2

query methods, 4.1.2

results, testing, 4.2.1

trace message, 4.2.2

R

REF CURSOR, 6.3, 6.3.2

accessing data, 6.3.2

CallableStatement, 6.3.2

declaring, 6.3.1

Oracle REF CURSOR Type, 6.3.1

REF CURSORs, 6.3.1

materialized as result set objects, 6.3.2

relative positioning in result sets, 4.1.3.1

result set enhancements

positioning, 4.1.3.1

scrollability, 4.1.3.1

sensitivity to database changes, 4.1.3.1

updatability, 4.1.3.1

result sets

declaring, 4.1.3.2

features, 4.1.3.1

ResultSet object, 4.1.3

closing, 8.1

getBoolean, 4.1.3

getInt, 4.1.3

getLong, 4.1.3

JDeveloper, creating in, 4.4.2

next method, 4.1.3

S

sample application

classes, 1.3

connecting, 3.3.1

DataHandler.java, 1.3

delete_action.jsp, 1.3

edit.jsp, 1.3

Employees.java, 1.3

employees.jsp, 1.3

error messages, 4.6.3

failed logins, 4.6.3

HR user account, 2.1.1.1

index.jsp, 1.3

insert_action.jsp, 1.3

insert.jsp, 1.3

JavaClient.java, 1.3

JSPs, 1.3

login functionality, 4.6

login interface, 4.6.4

login page, 4.6.2

login_action.jsp, 1.3

login.jsp, 1.3

overview, 1.3

security features, 4.6

testing, 1.3

update_action.jsp, 1.3

user authentication, 4.6

scriplets, 4.3.1.2

scriptlet

representation in JDeveloper, 4.4.2

scriptlets, 4.3.1.2, 4.3.1.2

scrollability in result sets, 4.1.3.1

sensitivity in result sets to database changes, 4.1.3.1

Sequenced Packet Exchange

Oracle JDBC OCI Driver, 1.1.2

SPX, 1.1.2

SQLException, 5.5

Statement object, 4.1.1

execute method, 4.1.2

executeBatch method, 4.1.2

executeQuery method, 4.1.2

executeUpdate method, 4.1.2

OraclePreparedStatement, 6.1.1

query methods, 4.1.2

stored function

calling, 6.2

stored function, creating, 6.2

stored procedures

calling, 6.2

creating, 6.2.1

Database Navigator, 6.2.1

JDeveloper, 6.2.1

OracleCallableStatement, 6.1.2

style sheets, using, 4.3.1, 4.3.4

T

testing

connection method, 4.2.2

filtered data, 4.5.2

JavaClient.java, 4.5.2

login feature, 4.7

query results, 4.2.2

TNS listener, 1.1.1

Transparent Network Substrate listener, 1.1.1

TTC protocol, 1.1.1

Two-Task Common protocol, 1.1.1

U

updatability in result sets, 4.1.3.1

update_action.jsp, 1.3

updating data, 5.2.5

edit.jsp, 5.2.5

Java class, 5.2

JSP pages, 5.2.4

update action, handling, 5.2.5

update_action.jsp, 5.2.5

user authentication, 4.6.1

V

view project, 7.4

W

Web server, 2.1.5

Apache Tomcat, 2.1.5

servlet container, 2.1.5

web.xml, 5.6

X

X/Open SQL Call Level Interface, 1

Figure 3-3 shows the Structure window, which displays a list of all the elements of the object being edited in JDeveloper. In this image, it shows the structure of the Employees table, which is selected in the Database Navigator. The Structure window is situated below the Database Navigator on the left hand side of the JDeveloper UI. Also, you can see the table definition in the main editing area of JDeveloper, in the center of the screen. This information includes details about the primary keys, column data types, and size.

Figure 3-1 shows the Create Database Connection screen of JDeveloper. In this screen you specify all the details required to connect to Oracle Database. These include the connection name, user name password, driver type, host name, port number, and service name, that are specified in text fields on the screen.

This image shows the Generate Accessors dialog box. You can select the variables for which you would like to generate accessors in the Employee JavaBean in this dialog box. There are checkboxes next to each of the variables in the JavaBean to select specific variables. To generate accessors for all variables, you can select the checkbox You can select all variables to generate accessors for by selecting the JavaBean checkbox, that is the Employee checkbox.

This figure shows the login page for the sample application as it appears in a browser. This page accepts user input for host name, user name, and password. This input is accepted using text fields. A submit button is present to submit the values for processing.

This image shows the insert_emp.jsp page in the Visual Editor. It shows an HTML form with a formatted static text heading, an HTML table with two columns, and an Add Employee button. The HTML table contains two columns. The left column contains labels for the data input fields in the right-hand side column. The text fields can be used to specify employee details such as First Name, Last Name, Email, and so on. After filling in all the details, you use the Add Employee button to insert the employee record into the employees table.

This image shows a further modified employees.jsp page in a browser. In this image, the column that contains the links to edit an employee record, now also contains a Delete link for every employee record. It is displayed alongside the Edit link in each row.

This image shows the output of the test program in the Log window. It displays the output of the query as four columns of data from the Employees table. It also displays the SQL query statement that produced this search result from the database.

This figure shows HTML form components in a JSP page in the Visual Editor: a text field and a button. These appear the same way as they would on the JSP page in a browser.

This image shows the employees.jsp page in a browser. In addition to the employee data and the edit links for each employee record, this page shows the Insert Employee link in the column heading field of the column that contains the Edit links for each employee. This column is the last column of the table and the Insert Employee link is in the top right-hand corner cell of this table.

This figure shows the employee.jsp page in the browser with filtered output from the employees table. The filtered data is displayed in an HTML table. The data shown in this figure has been filtered with the string "ing" and displays only the records of the employees whose names have an occurrence of this string.

This image shows the Add Library dialog box. You explicitly select the Java libraries that you want to use in your application from this dialog box. After adding a library to the application, it is displayed in the list of libraries in the Project Properties dialog box.

This image shows how the Java Code Insight feature in JDeveloper automatically prompts you with a list of valid functions when you are typing code. You can select the function you intend to use from this list, press the Enter key, and it is automatically inserted into the code file. This list is displayed in the Java Source Editor where you enter code.

Figure 1-2 illustrates how the JSP pages developed in the JDBC application are related.

The relationship diagram illustrates the possible flows of user activity through the application. The user first accesses the index.jsp page and proceeds to the login.jsp page to log in. The login_action.jsp verifies the user credentials and forwards authenticated users to the employees.jsp page. Depending on the action selected by the user on the employees.jsp page, the user is led to the insert.jsp page, the edit_emp.jsp page, or the delete_action.jsp page. These pages allow the user to insert a new employee record, modify an existing employee record, or delete an existing employee record, respectively.

This image shows the Java Source Editor with a modified insert_emp.jsp page. In addition to a UseBean representation of an employee record and a table with input controls and associated labels, there is are two options of which only one can be selected at a time. One option allows you to insert the employee record using JDBC, and other option allows you to insert the record using a stored procedure.

This figure shows the Import dialog box, which is displayed when you click on the Import property in the Property Inspector. The import dialog box displays a list of packages that you can select from to import into the JSP page.

This image shows the representation of all the components of the login.jsp page in the Visual Editor. These components include scriptlets, text fields, and an HTML button.

This image shows the structure of the ListBox control in the Structure Window. Earlier this field was populated with a fixed number of hard-coded values that are displayed as a tree. In addition, the ListBox tree also contains a scriptlet that can populate the listbox dynamically from a table in a database. If the script is to be used, the hard-coded values must be deleted. This image shows the hard-coded options being deleted.

This image shows the insert_emp.jsp page displayed in a browser. This image shows how the value for Job is selected from a dropdown list instead of being specified as text input.

This figure shows the employee.jsp page in a browser. It shows data for all employees from the HR database in an HTML table. When the user first logs in, this output is displayed to the user. There is a text field that accept a text string as a filter criterion. The accompanying Filter button is used to submit this string value for the search.

This image is a diagram that illustrates the relationship between the files of the master-detail application, browse.jsp and query.jsp.

This image shows the insert_emp.jsp page displayed in a browser. This shows the list that is populated from the database using a script instead of using hard-coded values.

Figure 3-6 shows the Javadoc displayed in the JDeveloper. This is displayed in the centre of the screen, in the same position as the main editing area.

Figure 3-8 shows the Java Source Editor window with the default code that is generated by JDeveloper for the newly created DataHandler class.

This figure shows the representation of a table in a JSP Page in the JDeveloper Visual Editor. This table contains dynamic data that is retrieved from the database using a script. For this reason, a scriptlet is displayed instead of actual data rows under the column heading row.

This image shows the edit.jsp page in a browser. This page contains, apart from formatted static text (heading, rule, and so on), an HTML table with two columns. The left column contains labels for the employee data that is retrieved from the database, such as First Name, Last Name, Email, and so on. The right-hand side column contains text fields populated with data for an employee. At the bottom of the page is an update button to submit any changes made to the data in the text fields.

This image shows the insert_emp.jsp page as shown in the browser with the options to insert an employee data using JDBC or through a SQL stored procedure. It also contains a table with form input controls and associated labels. There is also an Add Employee button that submits these values when the employee details are specified.

Figure 3-5 shows the Go to Java Class dialog box. This dialog box is used to specify the name of the Java class that you would like to view the Javadocs of.

This image shows the Java Source Editor window in JDeveloper. For static data, the Java Source Editor acts as a WYSIWYG (What You See Is What You Get) editor. It shows text formatted with the applied styles, as it would appear in the web page itself.

This figure shows the representation of a scriptlet in the JDeveloper Visual Editor. This looks like an HTML form button with the image of the symbolic representation of script on it. It is enclosed within a dotted line rectangle.

Figure 3-2 shows the Connections Navigator, which is located in the top left-hand corner of JDeveloper. It shows a hierarchical navigation tree, that allows you to view all the objects accessible from a connection. This connection could be to a database, an application server, a UDDI registry, and so on. In this image, the Connections Navigator displays all the objects accessible by connecting to Oracle Database. You can view the structure for the database, the HR schema, and all the objects within the schema.

This image shows an error indication in the Structure Window. The object with the error is highlighted and the number of errors is displayed on top of the object hierarchy.

This image shows the representation of a useBean object on a JSP page in the Visual Editor. This looks like an HTML form button with useBean written on it. It is enclosed within a dotted line rectangle.

Figure 3-7 shows the Create Java Class dialog box. It accepts user input to create a Java class. In this dialog box, you specify a name for the Java class and the package to which it must belong. You also select the class or interface that it extends from a dropdown list. You can also specify if the class :

is a public class.

contains a default constructor.

contains a main method.

This image shows the employees.jsp page in a browser. This page shows all the data from the employees table in an HTML table. In addition, this table has an extra column that contains the Edit link for every record displayed.

This figure shows the JDeveloper tools that you can use to create JSP Pages: Visual Editor, Component Palette, and Property Inspector. The Visual Editor occupies most of the space on the left hand side of the JDeveloper user interface. The Component Palette and Property Inspector are longish windows arranged one below the other on the right side. The Component Palette contains a list of form controls that you can drag and drop on to the page. The Property Inspector displays the properties associated with the selected form control, and allows you to modify them by specifying values for each property.

This image shows the edit_emp.jsp in the Visual Editor. Most of the data on this page is dynamic, so the page contains scriptlets and UseBeans in the order that they would appear in the actual source code. The page contains an HTML table to contain employee details in text fields. These values can be edited using the textfields. Further, in the Visual Editor, you see the representation of a script and not actual data. These scripts are used to populate the text fields with actual data depending on the search parameters provided. On the left side column of the table, there are labels for these text fields. Also, there is a submit button at the bottom of the table to submit any changes made to the values in the text fields.

Figure 1-1 illustrates the positions of the various windows displayed in the JDeveloper user interface in their default arrangement. This image shows:

The System, Application, and Connection Navigators, which are usually docked on on the top left hand corner of the screen.

The Code and Visual Editors are docked in the center of the screen

The Component Palette is on the top right corner of the screen.

The Structure window is on the bottom left of the screen.

The Property Inspector is below the Component Palette.

The Log Window is below the Code Editor and Property Inspector.

This figure shows the Scriptlet Properties dialog box. This dialog box consists of primarily a large text input area with OK and Cancel buttons. You use this text area to enter the code associated with the scriptlet.

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