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From Ameer Mawia <ameer.ma...@gmail.com>
Subject Re: My problem: I cannot successfully get or set a session attribute from a JSP file.
Date Sat, 06 Dec 2014 23:44:38 GMT
On Sun, Dec 7, 2014 at 2:49 AM, Jim Anderson <jim_anderson@centurylink.net>
wrote:

>
> Hi to all,
>
> I am currently developing some server side JSP code. By and large, things
> are progressing and working well. I have gotten half way decent at
> debugging my java/javascript/jquery/jsp/HTML source code, but I have run
> into a problem in JSP where the code does not work, but I have found no
> clues as to why it is not working.
>
> The environment that I am working in is Tomcat 7.0.54 and I am using java
> 1.8 and jquery 1.7.2.
>
> What I am trying to do:
>
> I have html code with an embedded javascript that runs jquery code. The
> jquery code being run makes an ajax call to a JSP file on the server side,
> which I will call s.jsp. This file is a very simple file whose sole
> function is to take a registration name and query an SQL database to see if
> the name has already been used at the web site. The registration name is
> passed with a method call that looks like this:
>
>         regName = request.getParameter("registrationName");    [item 1]
>
> This all works fine for me. So far so good. If the registration name is
> good, the state of my application logic changes. I guess there are multiple
> ways to store state, but I have chosen to store the state as a session
> variable.  I searched the net and found an example of JSP code that uses
> the session object to store information as an attribute with a statement
> that looks something like:
>
>         session.setAttribute("logicState","nameValidated"); [item 2]
>
> I tried adding this line and when I now push the submit button of my HTML
> form, which calls s.jsp as an action, the application hangs (in firefox). I
> receive no error messages anywhere. Usually, when I add bad code in s.jsp I
> will get a stacktrace from firefox or error messages in the firefox debug
> console, or both. Or I will error message in my own homegrown debug code,
> but that does not happen. I know that my home grown code does not get
> called, so I can infer that the call to s.jsp is never made, but I cannot
> be 100% certain of this. I also checked my tomcat/logs directory and there
> was nothing in the log files that I would not expect.
>
> So my first question is:  Can I simply add item 2, above, to my jsp file
> and expect that tomcat will recognize that I am referencing the session
> object?  In s.jsp, item 1, above, references the request object and tomcat
> handles that and I am expecting that it will also hand my reference to the
> session object.
>
> This should work. Make sure, you don't have the session disable on your
jsp i.e. your jsp don't have this directive:
<%@ page *session*="false" %>


> My second question is more general. My code is not working and there are
> no error messages. Can anyone speculate why this would be the case?  Is
> there any   place else I should be looking for error messages?
>
> There are many places to start debugging at. But first and foremost is
your application logs. What does your application logs says? Any exception,
corresponding stack-trace??

> Jim A.
>
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