Pass value servlet to jsp

Question

I want to pass value servlet to jsp. set value in servlet and use in jsp page

I getting NullPointerException below is my code

jsp

<body>
<%
  String message = (String) request.getAttribute("message");
  out.println("Servlet communicated message to JSP: "+ message);

  Vector vecObj = (Vector) request.getAttribute("vecBean");
  out.println("Servlet to JSP communication of an object: "+vecObj.get(0));
%>
</body>

java

public class ServletToJSP extends HttpServlet {
      public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {

        //communicating a simple String message.
        String message = "Example source code of Servlet to JSP communication.";
        request.setAttribute("message", message);

        //communicating a Vector object
        Vector vecObj = new Vector();
        vecObj.add("Servlet to JSP communicating an object");
        request.setAttribute("vecBean",vecObj);

        //Servlet JSP communication
        RequestDispatcher reqDispatcher = getServletConfig().getServletContext().getRequestDispatcher("javaPapers.jsp");
        reqDispatcher.forward(request,response);
      }
    }

Error Log I didnt do any chnages in web.xml I didnt do any chnages in web.xml

org.apache.jasper.JasperException: An exception occurred processing JSP page /javaPapers.jsp at line 21

18:   out.println("Servlet communicated message to JSP: "+ message);
19:  
20:   Vector vecObj = (Vector) request.getAttribute("vecBean");
21:   out.println("Servlet to JSP communication of an object: "+vecObj.get(0));
22: %>
23: </body>
24: </html>


Stacktrace:
    org.apache.jasper.servlet.JspServletWrapper.handleJspException(JspServletWrapper.java:553)
    org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:457)
    org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:391)
    org.apache.jasper.servlet.JspServlet.service(JspServlet.java:334)
    javax.servlet.http.HttpServlet.service(HttpServlet.java:722)


root cause 

java.lang.NullPointerException
    org.apache.jsp.javaPapers_jsp._jspService(javaPapers_jsp.java:83)
    org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:70)
    javax.servlet.http.HttpServlet.service(HttpServlet.java:722)
    org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:419)
    org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:391)
    org.apache.jasper.servlet.JspServlet.service(JspServlet.java:334)
    javax.servlet.http.HttpServlet.service(HttpServlet.java:722)


note The full stack trace of the root cause is available in the Apache Tomcat/7.0.12 logs.

Is vecObj throwing NullPointerException? Please share the stack trace — WarFox, Sep 03 '13 at 06:17
@RohitJain: I didnt do any chnages in web.xml please help me — Nick, Sep 03 '13 at 06:24
It's clear that your `vecObj` is `null`. But given your code, it doesn't look like it should happen. Do you have something in between your servlet and JSP. — Rohit Jain, Sep 03 '13 at 06:26
What happen if you remove the vector and try to print only the message? — Enrichman, Sep 03 '13 at 06:29
@RohitJain: No . any chnages in web.xml . or I just want to pass any value . if you can help — Nick, Sep 03 '13 at 06:30

score 0 · Answer 1 · answered Sep 03 '13 at 06:30

0

You might be getting NullPointerException because " reqDispatcher.forward(request,response);" creates a new request altogether and vecObj is becoming null because it does not exist in the request object. Instead of using reqDispatcher.forward use response.redirect .

answered Sep 03 '13 at 06:30

Chaitanya Gudala

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Isn't that actually opposite of what you are saying? – Rohit Jain Sep 03 '13 at 06:31
Please see this http://stackoverflow.com/questions/2047122/requestdispatcher-interface-vs-sendredirect – Chaitanya Gudala Sep 03 '13 at 06:34
You should also see. Specially the very first statement of accepted answer. – Rohit Jain Sep 03 '13 at 06:35
@RohitJain not working. when I remove Vector o/p like Servlet communicated message to JSP: null – Nick Sep 03 '13 at 06:35
The difference between these two scenarios has been very well explained by BalusC. – Chaitanya Gudala Sep 03 '13 at 06:35
@Nick : Is your problem solved ? If yes please do accept the answer – Chaitanya Gudala Sep 03 '13 at 06:45
@KrsnaChaitanya: Not solved . can you say me how to pass only single value servlet to jsp . – Nick Sep 03 '13 at 06:48
@Nick : The same way as you are doing it now. But instead of requestDispatcher use response.redirect("javaPapers.jsp"); . And also check "javaPapers.jsp" path is correct or not – Chaitanya Gudala Sep 03 '13 at 07:00

Pass value servlet to jsp

1 Answers1