Session Problem

[Mark Henryson]

Hi,

I tried the following coding for understanding the Session.

Servlet1.java
-------------
It is the form that having two fields 'name' and 'password'. When I submitted, it should go to servlet2.java with (Welcome name) and that screen will have another two fields 'age' and 'designation'. When I submitted this one, all the fields(name,password,age,designation) that are entered in the two forms should be displayed in the servlet3.java.

But it returning as Null for all the fields. If I am getting using request.getParameter("name"), it's working. but using session.getAttribute("name" is not working, returing null.

Below is my coding:

Servlet1.java
--------------
package com.example;
 
import javax.servlet.*;
import javax.servlet.http.*;
import java.io.*;
 
public class Session1 extends HttpServlet
{
   public void doGet(HttpServletRequest request, HttpServletResponse response)
                      throws IOException, ServletException
   {
       response.setContentType("text/html");
       PrintWriter out = response.getWriter();
    
       out.println("<form action=Session2.do>");
 
       out.println("<center><h1><b>"); 
       out.println("Example Program for Session Scope - Screen I"); 
       out.println("</b></h1></center><BR><BR>"); 
 
       out.println("<center>"); 
       out.println("Enter the Name"); 
       out.println("<input type=text name=user>");
       out.println("<BR><BR>"); 
 
       out.println("Enter the Password"); 
       out.println("<input type=text name=pass>");
       out.println("<BR><BR>"); 
       out.println("</center>"); 
 
       out.println("<center>"); 
       out.println("<input type=SUBMIT>");
       out.println("</center>"); 
       out.println("</form>");
  }
}

Servlet2.java
-------------
package com.example;
 
import javax.servlet.*;
import javax.servlet.http.*;
import java.io.*;
 
public class Session2 extends HttpServlet
{
   public void doGet(HttpServletRequest request, HttpServletResponse response)
                            throws IOException, ServletException
   {
       response.setContentType("text/html");
       PrintWriter out = response.getWriter();
 
       HttpSession sess = request.getSession();
       sess.setAttribute("Name", request.getParameter("user"));
       sess.setAttribute("Password", request.getParameter("pass"));   
 
       out.println("<center><h1><b>"); 
       out.println("Example Program for Session Scope - Screen II"); 
       out.println("</b></h1></center><BR><BR>"); 
 
       out.println("<center><h1><b>"); 
       out.println("Welcome" + " " + request.getParameter("user"));
       out.println("Welcome" + " " + sess.getAttribute("user"));
       out.println("</b></h1></center><BR><BR>"); 
 
       out.println("<form action=Session3.do>");
 
       out.println("<center>"); 
       out.println("Enter the Age"); 
       out.println("<input type=text name=age>");
       out.println("<BR><BR>"); 
 
       out.println("Enter the Designation"); 
       out.println("<input type=text name=des>");
       out.println("<BR><BR>"); 
       out.println("</center>"); 
 
       out.println("<center>"); 
       out.println("<input type=SUBMIT>");
       out.println("</center>"); 
       out.println("</form>");
   }
}

package com.example;
 
import javax.servlet.*;
import javax.servlet.http.*;
import java.io.*;
 
public class Session3 extends HttpServlet
{
   public void doGet(HttpServletRequest request, HttpServletResponse response)
                            throws IOException, ServletException
   {
      response.setContentType("text/html");
      PrintWriter out = response.getWriter();
     
      HttpSession sess1 = request.getSession();
      sess1.setAttribute("Age",request.getParameter("age"));
      sess1.setAttribute("Designation",request.getParameter("des"));
 
      out.println("<center><h1><b>"); 
      out.println("Example Program for Session Scope - Screen III"); 
      out.println("</b></h1></center><BR><BR>"); 
 
      out.println("Welcome " + " " + sess1.getAttribute("user"));
      out.println("<BR>");
      out.println("Your Password is " + " " + sess1.getAttribute("pass"));
      out.println("<BR>");
      out.println("Your Age is " + " " + sess1.getAttribute("age"));
      out.println("<BR>");
      out.println("Your Designation is " + " " + sess1.getAttribute("des"));
   }
}

web.xml
--------
<web-app xmlns="http://java.sun.com/xml/ns/j2ee"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee/web-app_2_4.xsd"
         version="2.4">
 
  <servlet>
    <servlet-name>Session Example1</servlet-name>
    <servlet-class>com.example.Session1</servlet-class>
  </servlet>
 
  <servlet-mapping>
    <servlet-name>Session Example1</servlet-name>
    <url-pattern>/Session1.do</url-pattern>
  </servlet-mapping>
 
  <servlet>
    <servlet-name>Session Example2</servlet-name>
    <servlet-class>com.example.Session2</servlet-class>
  </servlet>
 
  <servlet-mapping>
    <servlet-name>Session Example2</servlet-name>
    <url-pattern>/Session2.do</url-pattern>
  </servlet-mapping>
 
  <servlet>
    <servlet-name>Session Example3</servlet-name>
    <servlet-class>com.example.Session3</servlet-class>
  </servlet>
 
  <servlet-mapping>
    <servlet-name>Session Example3</servlet-name>
    <url-pattern>/Session3.do</url-pattern>
  </servlet-mapping>
 
</web-app>

[Pradeep bhatt]

The code does a session.setattribute("Name"...) but gets the value using sess.getAttribute("user"). The key used used in the set and get operation is different.
Replace sess.getAttribute("user") with sess.getAttribute("Name").