session.getAttribute is null?

[Bibhudutta Pradhan]

public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException
{
    HttpSession session = request.getSession();
    session.setAttribute("name", "MyName");
    response.sendRedirect("SecondServlet");
} 

Here is the Second Servlet

public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException
{
  HttpSession session = request.getSession();
  String name = (String)request.getSession().getAttribute("name");
  System.out.println(name);
}

name=null , in the SecondServlet
Whats the problem?

[Bibhudutta Pradhan]

Edit : for the second servlet
The SecondServlet is here.

 public void doGet(HttpServletRequest request, HttpServletResponse response)  
    throws ServletException, IOException  
    {   
      String name = (String)request.getSession().getAttribute("name");  
      System.out.println(name);  
    } 

[Mario Alcantara]

When you use response.sendRedirect("someLocation"), the servlet container create a new request and response object, and, if the request has not associated a session, when you call request.getSession(), a new session is created. You can use

RequestDispatcher rd = request.getRequestDispatcher("pathToServlet");
rd.forward(request, response);

insteand of

response.sendRedirect("SecondServlet");  

Thus, you send the current request and response, which have a session associated

PD. Sorry by my english

[Bear Bibeault]

A redirect does create a new request, but it should be participating in the same session. Changing to a forward is usually not an acceptable substitution.

Are you sure that the two servlets are in the same web app? Your redirect URL is also suspect. It should start with the context path.

[Mario Alcantara]

Bear Bibeault wrote:A redirect does create a new request, but it should be participating in the same session. Changing to a forward is usually not an acceptable substitution.

Are you sure that the two servlets are in the same web app? Your redirect URL is also suspect. It should start with the context path.

Hi Bear!

I have a question, why changing redirect to a forward is usually not an acceptable substitution?

Thanks

[Bear Bibeault]

Precisely because a forward does not create a new request, and a redirect does. When you need a new request, a forward is not acceptable. When you don't need a new request, a redirect is not acceptable.

They are not interchangeable.

[Bibhudutta Pradhan]

Hi Bear!

Both servlets are in the same web-app. Infact in the same package.
The Redirect URL without a context path also works for me.
But I have tried with a context path also. But with no results.

String contextPath = request.getContextPath();
response.sendRedirect(contextPath+"/loginAuth"); 

[William Brogden]

How about this diagnostic test. In your "second servlet" use the HttpSession method isNew() just to check.

If it is not new, use getAttributeNames to find out what it does have.

Bill

[thopex Arcilla]

try something like this in your second servlet:

public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException
{
String name = (String)session.getAttribute("name");
System.out.println("welcome" +name);
}

[Bibhudutta Pradhan]

Hi William Brogden. Thanks for your reply.
According to you I have tested like this :

System.out.println(session.isNew());         // true
if(session.isNew())
		{
			Enumeration enm = session.getAttributeNames();
			System.out.println("has more elements : " + enm.hasMoreElements());      //false
			while(enm.hasMoreElements())
			{
				System.out.println("element : " + enm.nextElement());
			}
		}

[Bear Bibeault]

And?

[Bibhudutta Pradhan]

session.isNew()

true

Enumeration enm = session.getAttributeNames(); 
enm.hasMoreElements());

false

[Bibhudutta Pradhan]

I cant understand now, that the same code I did a copy-paste in a new web application.
And it works fine.

I tried the old one by deleting the application from C:\Tomcat 6.0\work\Catalina\localhost\oldProject
don't work.

Then I tried to run it on my friend's computer. But did not work.


Then I created a new project from the scratch. And just copy paste the same code from the old project.
And its just working fine.

May it be a virus effect ??? I cant understand.
Please share your experience.

[Niraj Jha]

try this in second servlet:

HttpSession session = request.getSession(false);