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Last month we described two new specifications that define the handling of Web services in J2EE, JSR101/JAX-RPC, and JSR109. Both will be part of the J2EE 1.4 release, which is scheduled to go public by the end of the summer. In this article, we will show an example of an implementation of both new standards, which is provided in the Web Services Tech Preview for WebSphere Application Server 5.
This tech preview comes as a free download from the Web, giving you a head start on the new APIs. We will show you two examples, one that takes you through the creation of a Web service that is offered to external clients, and a second showing how to develop a client to an existing Web service.
We will assume that you are familiar with the basic Web services technologies like SOAP and WSDL. See the Resources section at the end for pointers to more material on those topics. We will also assume that you have read our previous article, "Web Services Standards" (WSDJ, Vol. 2, issue 3), describing the JSR1O1 and JSR109 specifications, or are otherwise familiar with them.
The WAS 5 Web Services Tech Preview
WebSphere Web Services for J2EE Technology Preview is based on the open-source Apache Axis project as a runtime engine, but also includes some enhancements, such as specialized serializers/deserializers for complex objects to obtain better performance. Axis is SAX-based, which makes it faster than implementations based on DOM parsers. Moreover, the deployment model is different; it follows the JSR109 specification, which Axis does not support.
It is important to note that the preview does not "support Axis"; instead, it supports the new standards and reuses some of the Axis work where it makes sense.
To obtain the tech preview installable package (approx. 10MB), download it from the WebSphere Developer Domain site at www7b.boulder.ibm.com/wsdd/downloads/web services.html. Before installing it, you must already have either WebSphere Application Server (WAS) version 5 or WebSphere Application Client version 5 installed. The installation process is pretty straightforward; simply follow the instructions.
For our example, the generated EAR (enterprise application archive) file will be deployed using the usual WAS deployment mechanisms, either through the Admin Console, or via the wsadmin tool. The tech preview installation modifies the WAS administration code so that there are two additional "dialogs" …