getAttribute resulting in java.lang.NullPointerException

Question

So I'm learning Servlet and JSP and I'm trying to send a String name to my jsp using RequestDispatcher but I'm getting java.lang.NullPointerException

DemoServlet.java

package com.shubhankar;

import java.io.IOException;

import javax.servlet.RequestDispatcher;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
@WebServlet("/DemoServlet")
public class DemoServlet extends HttpServlet {
    
    protected void doGet(HttpServletRequest request,HttpServletResponse response) throws ServletException, IOException
    {
        String name ="Harmless";
        request.setAttribute("label", "Harmless");
        RequestDispatcher rd= request.getRequestDispatcher("index.jsp");
        rd.forward(request, response);
        
    }   
}

index.jsp

<%@ page language="java" contentType="text/html; charset=ISO-8859-1"
    pageEncoding="ISO-8859-1"%>
<!DOCTYPE html>
<html>
<head>
<meta charset="ISO-8859-1">
<title>Insert title here</title>
</head>
<body>
<%

        String name=request.getAttribute("label").toString();
        out.println(name);
%>
</body>
</html>

Error

vaibhav0228 · Answer 1 · 2020-07-11T09:26:08.223

0

Use setAttribute (and getAttribute) when you need to pass objects around across many servlets (or other components) handling the same request.

Can you please try using setAttribute in your servlet and fetch the parameter using getParameter in the jsp

request.setAttribute("name", "Harmless");

above code in servlet.

and try to fetch in jsp as below
<%
  request.getParamter("name");
%>

edited Jul 11 '20 at 09:26

answered Jul 11 '20 at 08:54

vaibhav0228

49
7

hey when I add `request.setParameter("name", "Harmless");`in Servlet I get this error `The method setParameter(String, String) is undefined for the type HttpServletRequest` – Harmless Jul 11 '20 at 08:59
try request.setAttribute("name","Harmless") in servlet – vaibhav0228 Jul 11 '20 at 09:06
it shows the same error as servlet ie can't use getParameter with request – Harmless Jul 11 '20 at 09:11
``` request.getSession().setAttribute("name", "Harmless"); above code in servlet. and try to fetch in jsp as below <% session.getAttribute("name"); %> ``` – vaibhav0228 Jul 11 '20 at 09:39
I'm getting is null in name on my jsp page – Harmless Jul 11 '20 at 13:11
what is the attribute you are setting from servlet. i just gave an example request.getSession().setAttribute("name","Harmless") – vaibhav0228 Jul 11 '20 at 13:18
Yeah I too set the same attributes as `setAttribute("name","Harmless") ` – Harmless Jul 11 '20 at 13:23
Here is my output:https://i.stack.imgur.com/uDnKo.png I – Harmless Jul 11 '20 at 13:24
Hope you are calling the servlet which is redirecting to index.jsp. http://localhost:10311/JSTLDemo/DemoServlet – vaibhav0228 Jul 11 '20 at 13:49

getAttribute resulting in java.lang.NullPointerException

1 Answers1