Developing JAX-WS clients

Web services clients that can both access and invoke JAX-WS web services are developed based on the Web Services for Java Platform, Enterprise Edition (Java EE) specification. The application server supports Enterprise JavaBeans (EJB) clients, Java EE application clients, JavaServer Pages (JSP) files and servlets that are based on the JAX-WS programming model. Web services clients based on the JAX-RPC specification can invoke JAX-WS based web services if the Web Services Description Language (WSDL) file complies with the Web Services-Interoperability (WS-I) Basic Profile.

The JAX-WS client programming model supports both the Dispatch client API and the dynamic proxy client API. The Dispatch client API is a dynamic client programming model, whereas the static client programming model for JAX-WS is the dynamic proxy client. The Dispatch and dynamic proxy clients enable both synchronous and asynchronous invocation of JAX-WS web services.

The dynamic proxy client invokes a web service based on a service endpoint interface (SEI) that is provided. The JAX-WS dynamic proxy instances leverage the dynamic proxy function in the base Java SE Runtime Environment (JRE) 6. You must begin with a WSDL file if you are developing a static client.

In contrast, the Dispatch client API, javax.xml.ws.Dispatch, is an XML messaging-oriented client that is intended for advanced XML developers who prefer using XML constructs. The Dispatch API can send data in either PAYLOAD or MESSAGE mode. When using the PAYLOAD mode, the Dispatch client is only responsible for providing the contents of the soap:Body and JAX-WS includes the payload in a soap:Envelope element. When using the MESSAGE mode, the Dispatch client is responsible for providing the entire SOAP envelope. You do not need a WSDL file if you are developing a dynamic client.

To develop web services clients based on the JAX-WS programming model, you must determine the client model that best suits the needs of your web service application. If you want the web services client to invoke the service based on service endpoint interfaces with a dynamic proxy, use the Dynamic Proxy API to develop a static web service client. After the proxies are created, the client application can invoke methods on these proxies just like a standard implementation of the service endpoint interfaces. However, if you want to work directly with XML rather than a Java abstraction and work with either the message structure or the message payload structure, use the Dispatch API to develop a dynamic web service client. Read about implementing dynamic JAX-WS web services clients to learn how to develop dynamic web services clients.

Complete this task to develop a static web services client starting with a WSDL file.

To invoke web services asynchronously using a static or dynamic JAX-WS client, determine if you want to implement the callback or the polling model. Read about invoking JAX-WS web services asynchronously for more information regarding implementing asynchronous callback or polling for web service clients. The JAX-WS programming model for the service and client uses annotations to represent the same information that was provided in JAX-RPC client binding in a vendor-neutral manner.

The application server supports both managed and unmanaged web services clients when using the JAX-WS programming model:

• Managed clients

  Web services for Java EE clients are defined by Java Specification Requirements (JSR) 109 and are managed clients because they run in a Java EE container. These clients are packaged as enterprise archive (EAR) files and contain components that act as service requesters. These components are comprised of a Java EE client application, a web component such as a servlet or JavaServer Pages (JSP), or a session Enterprise JavaBeans (EJB). Web services managed clients use JSR 109 APIs and deployment information to look up and invoke a web service.

  For the managed clients, you can use Java Naming and Directory Interface (JNDI) look up to perform service lookup, or you can use annotations to inject instances of a JAX-WS service or port. Read about setting up UserName token Web Services Security, digital signature Web Services Security and Lightweight Third-Party Authentication (LTPA) token Web Services Security. The following code is an example of a context lookup that is JSR 109 compliant:

  InitialContext ctx = new InitialContext();
      FredsBankService service
  =(FredsBankService)ctx.lookup("java:comp/env/service/FredsBankService");
      FredsBank fredsBank = service.getFredsBankPort();
      long balance = fredsBank.getBalance();

  You can use the @WebServiceRef or @Resource annotation to declare managed clients. The usage of these annotations results in the type specified by the annotation being bound into the JNDI namespace. When the annotations are used on a field or method, they also result in injection of a JAX-WS service or port instance. You can use these annotations instead of declaring service-ref entries in the client deployment descriptor. You can still use the client deployment descriptor to declare JAX-WS managed clients, similar to JAX-RPC managed clients. You can also use the deployment descriptor to override and augment the information specified by @WebServiceRef and @Resource annotations. Use the @WebServiceRef annotation to bind and inject a JAX-WS service or port instance. You can only use the @Resource annotation to bind and inject a JAX-WS service instance. The use of either of these annotations to declare JAX-WS managed clients is only supported in certain class types. Some of these class types include JAX-WS endpoint implementation classes, JAX-WS handler classes, enterprise bean classes, and servlet classes.

  The following example uses the @WebServiceRef annotation to obtain an instance of FredsBank:

  @WebServiceRef(name=”service/FredsBankPort”, value=FredsBankService.class)
  FredsBank fredsBank;

  Now within the class, the fredsBank field does not have to be initialized. You can use this field directly:

  long balance = fredsBank.getBalance();

  You can also use the @WebServiceRef annotation to obtain instances of JAX-WS service classes; for example:

  @WebServiceRef(name=”service/FredsBankService”)
  FredsBankService service;

  Now within the class, the service field does not have to be initialized. You can use this field directly:

  FredsBank fredsBank = service.getFredsBankPort(); long balance = fredsBank.getBalance();

  In addition to the @WebServiceRef annotation, you can use the @Resource annotation to obtain an instance of JAX-WS service classes; for example:

  @Resource(name="service/FredsBankService", type=FredsBankService.class)
  FredsBankService service;

  As with the @WebServiceRef annotation, you can now use the service field without instantiation; for example:

  FredsBank fredsBank = service.getFredsBankPort(); long balance = fredsBank.getBalance();

  You can use the @Resource or @WebServiceRef annotations on a class. In this case, JNDI must be used to lookup the JAX-WS service or port; for example:

  @WebServiceRef(name="service/FredsBankService", type="FredsBankService")
  public class J2EEClientExample {
  		…
  		…
  
  		public static void main(String[] args) {
  			…
  			…
  		InitialContext ctx = new InitialContext();
  FredsBankService service =(FredsBankService)ctx.lookup("java:comp/env/service/FredsBankService");
      	FredsBank fredsBank = service.getFredsBankPort();
      	long balance = fredsBank.getBalance();  
  
  	}
  	…
  }

  For more information on using the @WebServiceRef and @Resource annotations, see the specifications for JSR-109, JSR-224, JSR-250, and Java Platform Enterprise Edition 5 (Java EE 5).

  As mentioned previously, when using annotations or JNDI to obtain instances of JAX-WS services and ports, do not instantiate the returned objects. Doing so results in an unmanaged client instance. The following example shows an example of incorrect usage:

  @WebServiceRef(name="service/FredsBankService")
  FredsBankService service;
  service = new FredsBankService(); // client becomes unmanaged.

  For JAX-WS managed clients that are declared by the @WebServiceRef or @Resource annotation and for clients that are declared using service-ref entries in the client deployment descriptor, you can use the administrative console to supply the endpoint URL that the client uses. This specified URL overrides the endpoint URL in the WSDL document that is used by the client. To learn more about specifying this endpoint URL, see the configuring web services client bindings documentation.

• Unmanaged clients

  Java Platform, Standard Edition (Java SE 6) clients that use the JAX-WS runtime environment to invoke web services and do not run in any Java EE container are known as unmanaged clients. A web services unmanaged client is a stand-alone Java client that can directly inspect a WSDL file and formulate the calls to the web service by using JAX-WS APIs. These clients are packaged as JAR files, which do not contain any deployment information.