Developing and deploying Web services clients

You can develop Web services clients based on the Web Services for Java 2 Platform, Enterprise Edition (J2EE) specification and the supported Web services development programming models.

About this task

The Web services client programming model provides the guidelines for accessing Web services in a J2EE environment. Web services clients can be developed based on the Web Services for Java 2 Platform, Enterprise Edition (J2EE) specification and the Java API for XML-based remote procedure call (JAX-RPC) specification. The application server supports the following two types of basic JAX-RPC Web services clients:
  • Managed clients

    Web services for J2EE clients are defined by Java Specification Requirements (JSR) 109 and are known as managed clients because they run in a J2EE container. These clients are packaged as enterprise archive (EAR) files and contain components that act as service requesters. These components can be a J2EE 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, the service lookup is through Java Naming and Directory Interface (JNDI) lookup. 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 is an example of a context lookup that is JSR 109 compliant:

    InitialContext ctx = new InitialContext();
        FredsBankServiceLocator locator
    =(FredsBankService)ctx.lookup("java:comp/env/service/FredsBankService");
        FredsBank fb = locator.getFredsBank(url);
        long balance = fb.getBalance();  

    When you are instantiating a context lookup for a managed client, do not use new() for the service locator. Here is an example that is not JSR 109 compliant (new ServiceLocator):

    Properties prop = new Properties();
        InitialContext ctx = new InitialContext(prop);
        FredsBankServiceLocator locator = new FredsBankServiceLocator();
        FredsBank fb = locator.getFredsBank(url);
        long balance = fb.getBalance(); 

    Without the lookup() call, the client has no access to the deployment descriptor. The Web services security configuration is in the Web services deployment descriptor.

  • Unmanaged clients

    J2SE clients that use the JAX-RPC run time to invoke Web services and do not run in any J2EE 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 the JAX-RPC APIs directly. These clients are packaged as JAR files which do not contain any deployment information.

For a Java application to act as a Web service client, a mapping between the Web Services Description Language (WSDL) file and the Java application must exist. The mapping is defined by the Java API for XML-based RPC (JAX-RPC) specification. You can use a Java component to implement a Web service by specifying the component interface and binding information in the WSDL file and designing the application server infrastructure to accept the service request. This entire process is based on the Web Services for J2EE specification. The JAX-RPC specification defines the mapping between a WSDL file, Java code and XML Schema types.

Procedure

  1. Obtain the Web Services Description Language (WSDL) document for the Web service that you want to access.

    You can locate the WSDL from the services provider through e-mail, through a Uniform Resource Locator (URL) or by looking it up in a Universal Description, Discovery and Integration (UDDI) registry.

  2. Develop client bindings from a WSDL file.

    The WSDL2Java command-line tool is run against your WSDL file to develop client bindings.

    The information needed to invoke the Web service is generated, including the service endpoint interface and implementations, the generated service interface and the ibm-webservicesclient-bnd.xmi and ibm-webservicesclient-ext.xmi deployment descriptors.

  3. Complete the client implementation. Write your client application code that is used to invoke the Web service.
    See Chapter 4 of the JSR 109 specification. You can access the specification through Web services: Resources for learning.
    Note: If an application creates a number of threads in the JSR 109 client, the meta data (including the WebSphere Application Server configuration) is not copied to the thread, and the Global Security Handler is not called.

    You can also review the GetQuote client in the WebServicesSamples application that is available in the Samples Gallery.

  4. (Optional) Assemble a Web services-enabled client Java archive (JAR) file into an enterprise archive (EAR) file. Complete this step if you are developing a managed client that runs in the J2EE client container.
  5. (Optional) Assemble a Web services-enabled client Web archive (WAR) file into an enterprise archive (EAR) file. Complete this step if you are developing a managed client that runs in the J2EE client container.
  6. (Optional) Configure the client deployment descriptor . Complete this step if you are developing a managed client that runs in the J2EE client container.
  7. (Optional) Configure the ibm-webservicesclient-bnd.xmi deployment descriptor. Complete this step if you are deploying a managed client that runs in the J2EE client container and you want to override the default client settings. See ibm-webservicesclient-bnd.xmi assembly properties for more information about the ibm-webservicesclient-bnd.xmi deployment descriptor.
  8. (Optional) Deploy the Web services client application. Complete this step to deploy a managed client that runs in the J2EE client container.
  9. Test the Web services-enabled client application. You can test an unmanaged client JAR file or a managed client application.

Results

You have created and tested a Web services client application.

What to do next

After you develop a Web services application client, and the client is statically bound, the service endpoint used by the implementation is the one that is identified in the WSDL file that you used during the development process. During or after installation of the Web services application, you might want to change the service endpoint. You can change the endpoint with the administrative console or the wsadmin scripting tool.




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Last updated: Aug 29, 2010 8:25:23 PM CDT
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