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Distributing Modular Applications: Developing Web Services

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Objectives

After completing this lesson, you should be able to do the following:

• Identify the components that can be exposed as Web services with Oracle Application Server 10g

• Develop, deploy, and test a stateless Java class Web service by using Oracle JDeveloper 10g

• Use the Web services home page to test the deployed Web service

• Identify the steps that are involved in exposing a PL/SQL stored procedure as a Web service

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Oracle Application Server 10g Web Services

Oracle Application Server 10g Web services can be implemented as any of the following:• Stateless and stateful

Java classes• Stateless PL/SQL

packages• Stateless session

Enterprise JavaBeans (EJBs)

• Java Message Service (JMS) destinations

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Developing a Web Service with a Stateless Java Class

1. Define an interface.

2. Define a stateless Java class.

3. Generate an .ear file.

4. Deploy the generated .ear file to Oracle Application Server 10g.

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Defining an Interface

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Defining an Interface

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Defining a Stateless Java Class

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Defining a Stateless Java Class

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Creating the Web Service

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Creating the Client Application

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Creating the Client Application

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Deploying the Web Service

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Testing the Web Service

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Web Service Home Page

A Web service home page provides:

• A link to the service description (WSDL file)

• Links to Web service test pages to test the available operations of the Web service

• Links to the Web service client-side Proxy Jar

• Links to the Web service client-side Proxy Source

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Testing the Deployed Web Service with Home Page

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Testing the sayHello Operation

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Testing the sayHello Operation

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Serializing and Encoding Parameters and Results

• Oracle Application Server 10g Web services support a prepackaged implementation for handling encoding, decoding, serialization, and deserialization.

• Oracle Application Server 10g supports the following encoding mechanisms:

– Standard SOAP v.1.1 encoding

– Literal XML encoding

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Developing a Stored Procedure Web Service

1. Set up data sources in OC4J by configuring the data-sources.xml file in the ORACLE_HOME\j2ee\home\config folder.

2. Generate the Java wrapper classes for the PL/SQL package and generate the EAR file.

3. Deploy the EAR file to Oracle Application Server 10g or stand-alone OC4J to expose it as a Web service.

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Generating Wrapper Classes Using JPublisher

Database JPublisher Java classes

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Exposing a Function as a Web Service by Using Oracle JDeveloper 10g

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Publishing the Package as a Web Service

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JMS Web Services

• Oracle Application Server 10g supplies a servlet to support two operations on messages:– Send operation – Receive operation

• The JMS Web service determines how to handle incoming and outgoing messages from JMS destinations.

• JMS messages can be processed on the server side by:– Message-Driven Bean (MDB) – JMS client

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Summary

In this lesson, you should have learned how to:

• Expose a stateless Java class as a Web service

• Test the Web service with the Web service home page

• Use Oracle JDeveloper 10g to develop, deploy, and test Web services

• Expose a PL/SQL stored procedure as a Web service

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Practice 19-1: Overview

This practice covers the following topics:

• Exposing a stateless session bean as Web service by using Oracle JDeveloper 10g

• Deploying the Web service to an embedded OC4J server and testing it with a client application

• Deploying the Web service to Oracle Application Server 10g and testing it with the Web services home page