Question

[Yuna Zhang <yu...@site.uottawa.ca>]

Hi There , 
I meet a problem when I would like to forward a request to other jsp page. My code is as following:

 public void doPost(HttpServletRequest req, HttpServletResponse res)
   throws ServletException,IOException {

  String uName = null;
  String userId = req.getParameter("userId");
  String password = req.getParameter("password");
  PrintWriter ot = res.getWriter();
  ot.println(" Please verify the Userid and password" + userId + "sdgsgdfsfd"+password);
 
try {

 uName = userValidate(userId, password);
 
 ot.println(" Please verify the Userid and password" + uName);
}
 catch(ClassNotFoundException e) { 
  System.out.println("Driver not found."); 
 System.out.println(e.toString());

 } catch(SQLException e) { 
   System.out.println("An error occurs.");
  System.out.println(e.toString());

 }catch(Exception e) { 
   System.out.println("An error occurs.");
  System.out.println(e.toString());

 }

/************************************************************
** call a method to validate the password which will return the 
** User Name for authorized users and null string for un-authorised. 
**********************************************************/


  if (uName == null)
       {

 
        ot.println(" Please verify the Userid and password");
        ot.close();
       }
  else
       {

   // So the user is valid let's create a seesion    // for this user.
   
  
      HttpSession userSession = req.getSession(true);

   // put the user name session variable.
 
      userSession.putValue("userName", uName);

  // now we need to transfer the control to welcome.jsp

      RequestDispatcher rd = 
 getServletContext().getRequestDispatcher("/../../jsp/welcome.jsp");

      file://if (rd != null)
        // {
   rd.forward(req,res);
   ot.println("ggggggggggg");
   
         file://}
         
         
         

       }


  }// end of doPost



The errors comes as following.

HTTP Status 500 - 

--------------------------------------------------------------------------------

type Exception report

message 

description The server encountered an internal error () that prevented it from fulfilling this request.

exception 

java.lang.NullPointerException
	at heartpro.Login1.doPost(Login1.java:198)
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:760)
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:853)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:247)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:193)
	at filters.ExampleFilter.doFilter(ExampleFilter.java:149)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:213)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:193)
	at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:256)
	at org.apache.catalina.core.StandardPipeline$StandardPipelineValveContext.invokeNext(StandardPipeline.java:643)
	at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:480)
	at org.apache.catalina.core.ContainerBase.invoke(ContainerBase.java:995)
	at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:191)
	at org.apache.catalina.core.StandardPipeline$StandardPipelineValveContext.invokeNext(StandardPipeline.java:643)
	at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:494)
	at org.apache.catalina.core.StandardPipeline$StandardPipelineValveContext.invokeNext(StandardPipeline.java:641)
	at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:480)
	at org.apache.catalina.core.ContainerBase.invoke(ContainerBase.java:995)
	at org.apache.catalina.core.StandardContext.invoke(StandardContext.java:2415)
	at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:180)
	at org.apache.catalina.core.StandardPipeline$StandardPipelineValveContext.invokeNext(StandardPipeline.java:643)
	at org.apache.catalina.valves.ErrorDispatcherValve.invoke(ErrorDispatcherValve.java:171)
	at org.apache.catalina.core.StandardPipeline$StandardPipelineValveContext.invokeNext(StandardPipeline.java:641)
	at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:172)
	at org.apache.catalina.core.StandardPipeline$StandardPipelineValveContext.invokeNext(StandardPipeline.java:641)
	at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:480)
	at org.apache.catalina.core.ContainerBase.invoke(ContainerBase.java:995)
	at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:174)
	at org.apache.catalina.core.StandardPipeline$StandardPipelineValveContext.invokeNext(StandardPipeline.java:643)
	at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:480)
	at org.apache.catalina.core.ContainerBase.invoke(ContainerBase.java:995)
	at org.apache.coyote.tomcat4.CoyoteAdapter.service(CoyoteAdapter.java:223)
	at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:594)
	at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.processConnection(Http11Protocol.java:392)
	at org.apache.tomcat.util.net.TcpWorkerThread.runIt(PoolTcpEndpoint.java:565)
	at org.apache.tomcat.util.threads.ThreadPool$ControlRunnable.run(ThreadPool.java:619)
	at java.lang.Thread.run(Thread.java:536)



--------------------------------------------------------------------------------

Thank you very much!

Yuna