Implementing Web Services using JAX-WS

Previously, I wrote a post describing the use of Apache Axis to create and consume Web Services from Java. In this post, I will describe how to use JAX-WS to create and consume web services. I used Glassfish application server for this application. The Web service and the Web Service client are both web applications.

The Service

1. Create a dynamic web project in Eclipse
2. Create the Web Service End point

   import javax.jws.WebMethod;
   import javax.jws.WebService;
   @WebService
   public class JaxWsService {
   @WebMethod
   public String sayHello(String message) {
   System.out.println("sayHello:" + message);
   return "You said '" + message + "'";
   }
   }

   JaxWsService.java
   
   • @WebService annotation is used to denote a Web Service End point.
   • Alternatively, you can have a Service End Point Interface (SEI). An SEI declares methods that can be invoked by clients.
3. Generate artifacts required for deploying, using wsgen: The wsgen.bat file is located in the GLASSFISH_HOME/bin directory. The following command can be used to create the artifacts

   C:\workspaces\WebServices\JaxWsTest\src>wsgen -classpath ../build/classes/ -wsdl -s . ws.JaxWsService

   You can see that I ran wsgen from my src directory (the project was created in eclipse).
4. Export the WAR file and deploy on Glassfish. To verify, go to the glassfish administrative console -> Web Services, you should see a Web service installed by the name JaxWsService. You might get an exception as shown below

   Error loading deployment descriptors for module [WebServicesEAR] -- (class: com/sun/xml/ws/modeler/RuntimeModeler, method: processRpcMethod signature: (Lcom/sun/xml/ws/model/JavaMethod;Ljava/lang/String;Ljavax/jws/WebMethod;Ljava/lang/String;Ljava/lang/reflect/Method;Ljavax/jws/WebService;)V) Incompatible argument to funct

   This is due to JAXWS/JWSDP binaries in the classpath. Remove any WS jar files (appserv-ws.jar, webservices-tools.jar etc.) from your class path.

The Web deployment desciptor:

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns="http://java.sun.com/xml/ns/javaee" version="2.5" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd">  <display-name>JaxWsTest</display-name>
<welcome-file-list>
<welcome-file>default.jsp</welcome-file>
</welcome-file-list>
</web-app>

web.xml

The Client
For this example I used a web application as a client. A servlet that invokes the actual Web Service client, and the Web Service client class which uses invokes the web method.

1. Create a dynamic web application in Eclipse.
2. Generate the required artifacts using wsimport command. The command I used is shown below.

   C:\workspaces\WebServices\JaxWsClientWeb\src>wsimport  -s . http://localhost:8080/JaxWsTest/JaxWsServiceService?wsdl

3. Write the Servlet: The servlet uses the @WebServiceRef annotation, so that the server can inject the Web service reference into the servlet. The following is the code for the servlet.

   import java.io.IOException;
   
   import javax.servlet.ServletException;
   import javax.servlet.http.HttpServletRequest;
   import javax.servlet.http.HttpServletResponse;
   import javax.xml.ws.WebServiceRef;
   
   import ws.JaxWsServiceService;
   
   import client.JaxWsClient;
   
   public class JaxWsClientServlet extends javax.servlet.http.HttpServlet implements javax.servlet.Servlet {
   
     @WebServiceRef(wsdlLocation = "http://localhost:8080/JaxWsTest/JaxWsServiceService?wsdl")
     JaxWsServiceService service;
   
   public JaxWsClientServlet() {
   super();
   }
   
   protected void service(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
   JaxWsClient client = new JaxWsClient(service);
   response.getWriter().println(client.callService());
   response.getWriter().close();
   }
   }

   JaxWsClientServlet.java
4. Write the client class: The client class is a simple Java class, which uses the Service references generated by the wsimport command to invoke the Web Service. Following is the code for the client class.

   import ws.JaxWsService;
   import ws.JaxWsServiceService;
   
   public class JaxWsClient {
   JaxWsServiceService service;
   
   public JaxWsClient(JaxWsServiceService service) {
   this.service = service;
   }
   
   public String callService() {
       JaxWsService port = service.getJaxWsServicePort();
       String result = port.sayHello("Hello");
   return result;
   }
   }

   JaxWsClient
5. The Web Deployment Descriptor

   <?xml version="1.0" encoding="UTF-8"?>
   <web-app xmlns="http://java.sun.com/xml/ns/javaee" version="2.5" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
     xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd">
   <display-name>JaxWsTest</display-name>
   <display-name>JaxWsClientWeb</display-name>
   <servlet>
   <description></description>
   <display-name>clientServlet</display-name>
   <servlet-name>clientServlet</servlet-name>
   <servlet-class>servlets.JaxWsClientServlet</servlet-class>
   </servlet>
   <servlet-mapping>
   <servlet-name>clientServlet</servlet-name>
   <url-pattern>/clientServlet</url-pattern>
   </servlet-mapping>
   <welcome-file-list>
   <welcome-file>default.jsp</welcome-file>
   </welcome-file-list>
   </web-app>

   web.xml
6. Export WAR file and deploy. To test go to

   http://localhost:8080/JaxWsClientWeb/clientServlet