Getting Started with WebSphere Application Server

138 Getting Started with WebSphere Application Server Community Edition
Figure 7.8 – Response after calling the Web service from a servlet
7.3.4 Using service reference tag in a Java EE application
In the previous servlet, you accessed the Web Service by instantiating the Service class
manually. This method is not optimal because each time you process the servlet, you have
to create a new service instance. A better alternative is to use JNDI to directly access your
Web service without instantiating any Service class. This method requires you to add a
service-ref element to web.xml to provide the necessary information about the WSDL
file location, Service name, etc. Listing 7.8 provides and example of what you need to add
to web.xml.
services/Hello
com.ibm.wasce.samples.HelloBillService
http://localhost:8080/HelloServiceProject/Hello?wsdl
Listing 7.8 – The service reference tag
Let’s go through the elements that were added to web.xml:
1. service-ref-name - This is the name by which JNDI identifies your deployed
service. These services are located at java:comp/env/
2. service-interface - This is the interface which a client uses to access the Web
service and create necessary stubs under the covers. This interface must extend
either to javax.xml.ws.Service or javax.xml.rpc.Service. Note that this is not the
Service-Endpoint Interface that we used to deploy the service.
3. wsdl-file - The location of the WSDL file of the deployed web service.
The changes required to access the service are shown in Listing 7.9
protected void doPost(HttpServletRequest request, HttpServletResponse
response) throws ServletException, IOException {
PrintWriter out = response.getWriter();
String target = request.getParameter("target");
try {
Context ctx = new InitialContext();
HelloBillService billService =
(HelloBillService)ctx.lookup("java:comp/env/services/Hello");
HelloPeople bill = billService.getHelloBillPort();
out.println(bill.sayHello(target));
} catch (NamingException e) {