Re: Testing for a User in a Session (JSP/Servlet)

From:

Lew <lew@nospam.lewscanon.com>

Newsgroups:

comp.lang.java.help

Date:

Wed, 21 Feb 2007 10:46:06 -0500

Message-ID:

<5qudnVBKxo6j9EHYnZ2dnUVZ_qPinZ2d@comcast.com>

llama64 wrote:

My project is a simple web application that requires user
authentication. To accomplish this, the first page is a login JSP
that forwards a user's credentials to a loginCheck servlet. Upon
approval, it forwards to the main JSP of the app.

If a user has already logged in (User bean object created and in the
Session), I want it to redirect all requests to the main JSP rather
then the login JSP.

I created a tag to handle this but I ran into an endless loop. ...
Can anyone help me with the logic here? I want this tag to be usable
on all pages of the system, but I want to avoid the endless
redirecting that occurs when you get logged in and load "welcome.jsp".

I suggest looking into the Model-View-Controller paradigm for Web
applications. In this model, JSPs never handle navigation directly, they send
a request for navigation to a controller servlet, which uses a dispatch table
or similar mechanism to match the request, the permission and the target view.

So your code would move out of the tag library, where it is hard to debug,
into the controller servlet, where it is much easier.

This is the basis of the Struts framework.

- Lew