July 26, 2011, 4:12 a.m.
posted by maxidax
Mapping Java to WSDL and XML
As you learned in Chapter 5, WSDL documents describe a Web service so that, using SOAP, applications can access it from different operating systems and programming languages. WSDL names the operations that can be invoked and describes the exact format of SOAP messages, the Internet protocol used (for example, HTTP) and the Internet addresses of Web service endpoints.
JAX-RPC defines a J2EE standard programming model developers use to exchange SOAP messages based on WSDL document definitions. Specifically, JAX-RPC defines how developers can use WSDL documents to generate endpoint and service interfaces, and the classes that implement them. JAX-RPC can also be used to generate WSDL documents from endpoint interface definitions and configuration files. It's the purpose of this section to delve into the details of the JAX-RPC mapping of Java code to WSDL and XML documents.
The mapping between WSDL and Java was covered to some extent in Section 12-1: Generated Stubs, but this chapter will go into more depth—after covering the basics—including detailed coverage of the mapping between XML types declared by message definitions and the parameters of endpoint methods that employ the RPC/Literal and Document/Literal messaging modes.
This chapter will not attempt to teach you about WSDL or XML; it's assumed that you understand these technologies already. If any XML or WSDL features are unfamiliar, you can review the coverage of them in Chapter 3: The W3C XML Schema Language and Chapter 5: WSDL.