Re: connection pooling with servlets

From: David Durham <ddurham(at)vailsys(dot)com>
To: "J(dot)" <sweepingoar(at)yahoo(dot)com>
Cc: pgsql-jdbc(at)postgresql(dot)org
Subject: Re: connection pooling with servlets
Date: 2006-04-28 05:28:51
Message-ID: 4451A813.6030403@vailsys.com
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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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