Example: Developing a Web service from an EJB or JavaBeans implementation

This example takes you through the steps to develop a Web service from an EJB or JavaBeans implementation. The development process is based on the Web Services for J2EE specification.

1. Select the enterprise bean or JavaBeans implementation that you want to enable as a Web service.

   The implementation must meet the following Web Services for J2EE specification requirements:

   • It must have methods that can be mapped to a service endpoint interface. See step 2 for more information.

   • It must be a stateless session EJB implementation or a JavaBeans implementation without client-specific state, because the implementation bean might be selected to process a request from any client. If a client-specific state is required, a client identifier must be passed as a parameter of the Web service operation.

     The selected methods of an enterprise bean must not have a transaction attribute of mandatory, because no standard currently exists, for these Web services transactions.

     A JavaBeans implementation in a Web container requires the following contents:

     • A public default constructor
     • Exposed public methods
     • It must not save a client-specific state between method calls
     • It must be a public, non-final, and non-abstract class
     • It must not define a finalize method

2. Develop a service endpoint interface.

   Developing a Web service requires a service endpoint interface.

   If you are using an EJB implementation, develop a service endpoint interface from an EJB remote interface.

   If you are using a JavaBeans implementation, develop a service endpoint interface for a JavaBeans implementation.

3. Develop a Web Services Description Language (WSDL) file.

4. Develop deployment descriptor templates.

   If you are using an EJB implementation, develop Web services deployment descriptor templates from an EJB implementation.

   If you are using a JavaBeans implementation, develop Web services deployment descriptor templates for a JavaBeans implementation.

5. Configure the deployment descriptors.

   By setting the ejb-link or servlet-link values of the service-impl-bean elements one can link to the enterprise bean or JavaBeans implementation that implement the service.

   Configure the webservices.xml deployment descriptor.

   Configure the ibm-webservices-bnd.xmi deployment descriptor.

6. Assemble an enterprise archive (EAR) file from a JAR file or assemble an EAR file from a WAR file.

7. Enable the Web service-enabled EAR file.

   This step only applies if you are using an EJB implementation.

8. Deploy the Web service application.

9. Publish the WSDL file.

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Related Tasks

Developing Web services applications

 

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