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Tetaining session info between jsp page and servlet

Posted on 2005-04-11
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Last Modified: 2010-04-01
Hey,
I have I website that contains both jsp pages and servlets. In one of my jsp pages I set a session variable using

session.setAttribute("emp_id",rs.getString("emp_id"));

This information is held fine when I'm just navigating between jsp pages but when I go to a servlet and use

HttpServletRequest req;
req.getAttribute("emp_id").toString();

I get a null pointer exception. Help greatly needed and hugely appreciated,

aka_damo
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Question by:aka_damo
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4 Comments
 

Author Comment

by:aka_damo
ID: 13756737
Sorry,
That should be "Retaining session info between jsp page and servlet"
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Accepted Solution

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bloodredsun earned 500 total points
ID: 13756922
You need this

HttpSession session = request.getSession() ;
String emp_id = session.getAttribute("emp_id");
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LVL 29

Expert Comment

by:bloodredsun
ID: 13756966
In your example you are setting data into the session object and then trying to read it from the request object so it wil be null.( and there's a missed cast in my code)

setting JSP
---------------
session.setAttribute("emp_id",rs.getString("emp_id"));

getting JSP
---------------
String emp_id = (String)session.getAttribute("emp_id");//notice the cast to String as it actually returns an Object.

getting Servlet
---------------
HttpSession session = request.getSession() ;//get session object from the request object
String emp_id = (String)session.getAttribute("emp_id");//now as above


This is because the servlet container, such as tomcat, already provides you with the session object in the JSP so you don't need to worry about it.
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Author Comment

by:aka_damo
ID: 13757069
Cheers bloodredsun,
That works fine. I spotted the missed cast alright but I just used

emp_id = session.getAttribute("emp_id").toString();

Thanks again
aka_damo
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