gwt+spring deploy tomcat failed

[q1111]

gwt+spring run in host mode is fine. but when i deployed war in tomcat ,rpc call is wrong.
web.xml

  <servlet>
  <servlet-name>gwt-controller</servlet-name>
  <servlet-class>
   org.springframework.web.servlet.DispatcherServlet
  </servlet-class>
  
  <load-on-startup>2</load-on-startup>
 </servlet>
  <servlet-mapping>
  <servlet-name>gwt-controller</servlet-name>
  <url-pattern>*.gwt.rpc</url-pattern>
 </servlet-mapping> 

gwt-controller-servlet.xml

 <bean id="handlerMapping"
  class="org.springframework.web.servlet.handler.BeanNameUrlHandlerMapping" />
 <bean name="/testgwt5/greet.gwt.rpc"
  id="greetService"
  class="com.zeng.server.GreetingServiceImpl">
 </bean> 

GreetingService.java

@RemoteServiceRelativePath("greet.gwt.rpc")
public interface GreetingService extends RemoteService {
 String greetServer() throws IllegalArgumentException;
} 

TestGWT5.java

greetingService.greetServer(
      new AsyncCallback<String>() {
       public void onFailure(Throwable caught) {
        // Show the RPC error message to the user
        dialogBox
          .setText("Remote Procedure Call - Failure");
        serverResponseLabel
          .addStyleName("serverResponseLabelError");
        serverResponseLabel.setHTML(SERVER_ERROR);
        dialogBox.center();
        closeButton.setFocus(true);
       }
       public void onSuccess(String result) {
        dialogBox.setText("Remote Procedure Call");
        serverResponseLabel
          .removeStyleName("serverResponseLabelError");
        serverResponseLabel.setHTML(result);
        dialogBox.center();
        closeButton.setFocus(true);
       }
      }); 

when i deploy on tomcat ,always run to onFailure(Throwable caught){}
Please help me. thanks a lot.

[q1111]

GWTController.java

public abstract class GWTController extends RemoteServiceServlet implements  Controller, ServletContextAware{
 private static final Log log = LogFactory.getLog(GWTController.class);
 public ServletContext m_servletContext;
    
    public ModelAndView handleRequest (HttpServletRequest request, HttpServletResponse response) throws Exception
    {
     doPost (request, response);
        return null;
    }
    public void setServletContext (ServletContext servletContext)
    {
        this.m_servletContext = servletContext;
    }
    public ServletContext getServletContext ()
    {
        return m_servletContext;
    }
} 

GreetingServiceImpl.java

public class GreetingServiceImpl extends GWTController implements
  GreetingService {
 public String greetServer() throws IllegalArgumentException {
...
}
}