Andy, I use Poolman in a Struts application and did it this way:
Downloaded poolman-2.1-b1 (you can even use CVS to pull the latest
version from their site)
Configured poolman.xml to work with mysql 3.23.46/mm.mysql-2.0.8 and
stuck it in WEB-INF/classes of my web app
BTW this works for both tomcat 3.2.4 and 4.0.1 - with struts-1.0
Then I preload an initservlet on startup that grabs a Poolman
datasource.
It also tears down all pools in destroy()
This datasource is stored in a connectionholder object in the
servletcontext that acts as a wrapper for Poolman.
I used this extra layer of abstraction so I can pull a generic
datasource from the servletcontext and call methods such as
getConnection() and closeConnection() that in turn call the correct
methods in Poolman. That way, I can plug-and-play with alternative
connection pools without modifying my application objects.
// set up a connection pool with
// <dbName> from web.xml initparam
javax.sql.DataSource defaultPool =
PoolMan.findDataSource(dbName);
zConnectionHolder dsPool =
new zConnectionHolder();
dsPool.setDefaultPool(defaultPool);
context.setAttribute("dsPool", dsPool);
Then I proceed like you:
zConnectionHolder dsPool =
(zConnectionHolder) servlet.getServletContext()
.getAttribute("dsPool");
java.sql.Connection con =
dsPool.getConnection();
dsPool.closeConnection();
Works like a charm. Your error makes no mention of anything that looks
like a non-tomcat or non-struts object, so it's probably a config error
in setting up you web app with tomcat/struts
I work like this: develop in a source directory, then deploy to the
servlet container (with ant), with a "clean" target if needed, and then
bounce tomcat (and apache, if in the loop). I have even run into the
need to shut down tomcat, whack my web app *and* tomcat/work directories
before deploying - primarily on Unix. And - turn on as much debugging as
possible initially. *Logs are your friend*
Many pieces have to be happy for it all to work, and they will be happy
to let you know if they don't play well with other children. Also, don't
do what I do: fix 50 things at once, instead debug incrementally by
changing one thing at a time.
Be aware that mysql versions 3.23.36 and below fail miserably with
Poolman, as Poolman tries to set transaction levels and mysql barfs in
technicolor.
Andy Timm wrote:
>
> Hello. I am trying to implement a DB connection
> manager with my Struts webapp. I created a servlet
> that gets called when Tomcat is initialized, that
> creates a DbConnectionBroker, and puts it in the
> ServletContext:
> getServletContext().setAttribute("dbPool", dbPool);
>
> In a 'ActionForm', I'm validating a username against
> the database, so I grab the dbPool object to pass into
> my database bean:
> DbConnectionBroker pool =
> (DbConnectionBroker)servlet.getServletContext().getAttribute("dbPool");
>
> This works fine for the first page. When I attempt to
> access the next page (any other following page), right
> after the "checkLogin" tag is called, it throws the
> exception below. Two questions... First, I would
> like to utilize Struts datasource mapping, but don't
> know how to do so while using a different connection
> manager. (There was a post yesterday suggesting
> Poolman... ) Second, what am I doing wrong so that I
> cannot access my next page? The 'Action' called after
> the working page executes normally, then it dies. I'm
> loading two servlets (action, and my initDBPool) in
> web.xml. Is there some rule about which must be
> loaded first? I'm new to the whole servlet thing, but
> it seems like it's looking to my initDBPool servlet
> for information it should find elsewhere (hence the
> IncompatibleClassChangeError). I would be most
> grateful if someone could explaine the 'proper' method
> for merging connectionPooling with Struts - but I'd be
> happy for a solution for my problem at hand too...
> Thanks, Andy Timm
>
> java.lang.IncompatibleClassChangeError
> at
> _0002fregister_0002ejspregister_jsp_0._jspService(_0002fregister_0002
> ejspregister_jsp_0.java:578)
> at
> org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:119)
> at
> javax.servlet.http.HttpServlet.service(HttpServlet.java:853)
> at
> org.apache.jasper.servlet.JspServlet$JspServletWrapper.service(JspSer
> vlet.java:177)
> at
> org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:3
> 18)
> at
> org.apache.jasper.servlet.JspServlet.service(JspServlet.java:391)
> at
> javax.servlet.http.HttpServlet.service(HttpServlet.java:853)
> at
> org.apache.tomcat.core.ServletWrapper.doService(ServletWrapper.java:4
> 04)
> at
> org.apache.tomcat.core.Handler.service(Handler.java:286)
> at
> org.apache.tomcat.core.ServletWrapper.service(ServletWrapper.java:372
> )
> at
> org.apache.tomcat.facade.RequestDispatcherImpl.forward(RequestDispatc
> herImpl.java:194)
> at
> org.apache.struts.action.ActionServlet.processActionForward(ActionSer
> vlet.java:1758)
> at
> org.apache.struts.action.ActionServlet.process(ActionServlet.java:159
> 5)
> at
> org.apache.struts.action.ActionServlet.doGet(ActionServlet.java:491)
> at
> javax.servlet.http.HttpServlet.service(HttpServlet.java:740)
> at
> javax.servlet.http.HttpServlet.service(HttpServlet.java:853)
> at
> org.apache.tomcat.core.ServletWrapper.doService(ServletWrapper.java:4
> 04)
> at
> org.apache.tomcat.core.Handler.service(Handler.java:286)
> at
> org.apache.tomcat.core.ServletWrapper.service(ServletWrapper.java:372
> )
> at
> org.apache.tomcat.core.ContextManager.internalService(ContextManager.
> java:797)
> at
> org.apache.tomcat.core.ContextManager.service(ContextManager.java:743
> )
> at
> org.apache.tomcat.service.http.HttpConnectionHandler.processConnectio
> n(HttpConnectionHandler.java:210)
> at
> org.apache.tomcat.service.TcpWorkerThread.runIt(PoolTcpEndpoint.java:
> 416)
> at
> org.apache.tomcat.util.ThreadPool$ControlRunnable.run(ThreadPool.java
> :498)
> at java.lang.Thread.run(Thread.java:484)
>
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Software Engineer
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770-551-4528
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