[jboss-user] [JBoss Seam] - servlet in seam application

[jason_rency]

All,
my question may looks strange, 

I tried to get a common java servlet work within a seam application by adding the following line in web.xml: (calculator is the servlet name)

<servlet>
  |         <servlet-name>Calculator</servlet-name>
  |         <servlet-class>server.Calculator</servlet-class>
  |     </servlet>
  |     
  |     <servlet-mapping>
  |         <servlet-name>Calculator</servlet-name>
  |         <url-pattern>/Calculator</url-pattern>
  |     </servlet-mapping> 

the servlet worked fine (I called it from a mobile phone, that's why I need a servlet) after I deployed the seam app with this servlet. but when I tried to use the seam app itself by browser (the hotel booking example), it just didn't work. seems there are conflicts between the new lines I added and the old lines  in web.xml .

then I changed the servlet by adding ejb3 annotation (it's strange, huh? a ejb3 staless session bean servlet) and re-deploy the app again (with the new lines in the web.xml). then the servlet (also a session bean) worked well and the hotel booking example worked fine as normal.

then added persistency statement to this servlet (the session bean) but I got a NPE, which seems the  Entity manager is null and I can't get the entity manager properly in a servlet which is also a ejb3 session bean? 

the code is like this:

package server;
  | 
  | import javax.ejb.Stateless;
  | import javax.servlet.*;
  | import javax.servlet.http.*;
  | import java.io.*;
  | import java.text.*;
  | import javax.persistence.EntityManager;
  | import javax.persistence.PersistenceContext;
  | 
  | 
  | @Stateless
  | public class Calculator extends HttpServlet implements cacu 
  | {
  | 	@PersistenceContext
  | 	private EntityManager em;
  | 	private Reguser user;
  | 	
  | 	public void doPost(HttpServletRequest request,HttpServletResponse response)
  |        throws IOException, ServletException 
  |     {  
  |       response.setContentType("text/plain");
  | 	  PrintWriter out = response.getWriter();
  | 	  String uid = request.getParameter("uid");
  | 	  String passwd =request.getParameter("passwd");
  | 	  user = em.find(Reguser.class, "rency"); (exception here, em is null)
  | 	  String email = user.getEmail();
  | 	  System.out.print(email);
  | 	  out.println("just a test: "+ uid);
  |     }
  |    
  | }

exception was:

10:16:49,501 ERROR [[Calculator]] Servlet.service() for servlet Calculator threw exception
  | java.lang.NullPointerException
  | 	at server.Calculator.doPost(Calculator.java:26) (the entity manager)	at javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
  | 	at javax.servlet.http.HttpServlet.service(HttpServlet.java:810)
  | 	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:252)
  | 	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:173)
  | 	at org.jboss.web.tomcat.filters.ReplyHeaderFilter.doFilter(ReplyHeaderFilter.java:96)
  | 	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:202)
  | 	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:173)
  | 	at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:213)
  | 	at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:178)
  | 	at org.jboss.web.tomcat.security.SecurityAssociationValve.invoke(SecurityAssociationValve.java:175)
  | 	at org.jboss.web.tomcat.security.JaccContextValve.invoke(JaccContextValve.java:74)
  | 	at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:126)
  | 	at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:105)
  | 	at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:107)
  | 	at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:148)
  | 	at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:869)
  | 	at org.apache.coyote.http11.Http11BaseProtocol$Http11ConnectionHandler.processConnection(Http11BaseProtocol.java:664)
  | 	at org.apache.tomcat.util.net.PoolTcpEndpoint.processSocket(PoolTcpEndpoint.java:527)
  | 	at org.apache.tomcat.util.net.MasterSlaveWorkerThread.run(MasterSlaveWorkerThread.java:112)
  | 	at java.lang.Thread.run(Thread.java:595)


also I added a ejb3 web service in the app, the web service work well: code like this:

interface:

package server;
  | 
  | import javax.jws.WebService;
  | import javax.jws.WebMethod;
  | 
  | 
  | @WebService
  | public interface findEmail {
  | 	
  | 	 @WebMethod public String findemail(String username);
  | 	 
  | }

the implementation:

package server;
  | 
  | import javax.ejb.Stateless;
  | import javax.jws.WebService;
  | import javax.persistence.EntityManager;
  | import javax.persistence.PersistenceContext;
  | 
  | 
  | @Stateless
  | @WebService(endpointInterface="server.findEmail")
  | 
  | public class findemailimpl implements findemail {
  | 
  | 	@PersistenceContext
  | 	private EntityManager em;
  | 	private Reguser user;
  | 			
  | 	public String finduser(String username) 
  | 	{
  |                   em.find(Reguser.class, username);
  | 	  String email = user.getEmail();
  |                   return email;
  |                  }
  | }
  |     


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