Re: connection pooling with servlets - Mailing list pgsql-jdbc

From J.
Subject Re: connection pooling with servlets
Date
Msg-id 20060428061105.37423.qmail@web54215.mail.yahoo.com
Whole thread Raw
In response to Re: connection pooling with servlets  (David Durham <ddurham@vailsys.com>)
Responses Re: connection pooling with servlets  (David Durham <ddurham@vailsys.com>)
List pgsql-jdbc
Thanks.  I posted some of the relevant code here;

http://saloon.javaranch.com/cgi-bin/ubb/ultimatebb.cgi?ubb=get_topic&f=7&t=016798

But I'm still baffled as to how to get access to a session in a servlet that was called by a jsp.  Should servlets have access to sessions easily?  Everyone is making it seem like this shouldn't be a problem, but then I've read in other places that a jsp calling a servlet clears whatever attributes were part of the request object.

David Durham <ddurham@vailsys.com> wrote:
J. wrote:
> Thanks for replying. I'm not sure if that would help, but maybe if I
> understand the suggestion better it will.
>
> Right now I've got the index.jsp calling Login servlet via POST. Then
> Login creates the connection, puts it into a session with some other
> attributes and forward(req,res) to welcome.jsp.

Not much point in storing a datasource as a session attribute (1 datasource per application user?). More appropriate to make it application-wide by putting a datasource in a servlet context or, as someone else suggested, a static attribute/property/member/variable ... request.getSession().getServletContext().setAttribute(...). JNDI is another good place to put this sort of thing. An easy way to make sure your datasource is always available is to use a servlet context listener to create it when the application is initialized. Google for servlet context lifecycle should tell you how to do setup a listener.

Now, as for a null pointer on your connection object, maybe you have something misconfigured in your datasource. Username, password, host, and driver class are usual suspects.


> Welcome.jsp has a form
> that uses GET to call a Search servlet and this is where I get a null
> pointer on the connection object. I'm trying to get the session out of
> the request object, but it seems like the request loses state by the
> time I'm getting to it (in Search servlet).

Not sure. You can post your code and maybe get some help. Wait, is this homework?


-Dave



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