don't understand with behaviour with tomcat session

[Nikko]

Hi all,
I have got a web application(on tomcat server) in which clients have to
be logged to enter. And I would like to create only new user's session
if user's authentification is successful (login/password correct). So,
normaly the number of users logged = number of tomcat's sessions.
In my webapps, I use a 'AuthenticationFilter' which implement Filter
java Class . When user fill his login and password and click button
'enter', I pass in function 'doFilter '

public class AuthenticationFilter implements Filter
{
public void init(FilterConfig config) throws ServletException {}
public void doFilter(ServletRequest req, ServletResponse
res,FilterChain chain) throws IOException, ServletException
{
HttpSession session =
(HttpServletRequest)req).getSession(false);
//session is null, ok no problem
HttpServletRequest request = (HttpServletRequest)req;
//by casting req to HttpServletRequest, a session is created,
and I don't understand
HttpSession session2 = request.getSession(false);
//and now session2 is not null.
}

public void destroy() {}
}

I don't understand why when I do this : HttpServletRequest request
= (HttpServletRequest)req;
a new session is created, (I verified also in tomcat manager)
Has anybody already dealed with this problem?
I use eclipse too with wtp for debug.

 

[Harry]

Hi,

HttpServletRequest request = (HttpServletRequest) req;
should not do any change to session. As you know, it is just a simple
JAVA syntax casting the variable down the inheritance tree. So the
problem may not happen ONLY in this filter. Will it be something
happening on another thread in a servlet class that creates the
session?

To debug this case, I think the Tomcat Manager cannot reflect the
actual case, because when you see the Tomcat Manager, the whole
request already finishes. I suggest you to debug the code line by
line. Then, you can see whether the session is created before and
after your logic above.

Harry