In our forthcoming "Java XML programming with Servlets and JSP" (WROX,
within a month) we've implemented connection pooling, using a Singleton
class that extends a more general Cache class. Connection pools can be
dynamically created and accessed by their defining characteristics, i.e.,
dbUrl, username and password.
> -----Original Message-----
> From: D. J. Hagberg [mailto:[EMAIL PROTECTED]]
> Sent: Friday, December 03, 1999 5:13 PM
> Subject: Re: Connection Pool
>
>
> Cory L Hubert wrote:
> >
> > Ok. I am on a roll now. I am trying to setup a
> Connection Pool. I have
> > a few samples. But I don't know where to put it in my
> project. Should I
> > put it in the Beans? Or should I just make one
> connectionpool jsp file and
> > include it in all the pages?
> >
> > What is the best way? I know this is an opened end
> question but, I'd like
> > to hear a few suggestions.
>
> We have also written a simple singleton ConnectionGenerator class that
> has static poolCheckout(...) and poolCheckin(Connection)
> methods. These
> methods are used
> inside our *bean* code whenever a db connection in needed.
> This is done
> because
> you want to be sure to check the Connection back into a pool
> regardless
> of whether
> an exception occurred in your code or not, so you need a try/finally
> combo.
> We also use this combo to implement transaction rollback when
> multi-statement
> transactions are used.
>
> For example:
>
> boolean autoCommit = false;
> boolean committed = false;
> Connection c = ConnectionGenerator.poolCheckout();
> Statement s = null;
> try {
> // do some stuff that could possibly throw an exception.
> s = c.createStatement();
> s.executeUpdate("UPDATE x SET q=5");
> s.commit();
> s.close();
> committed = true;
> s = null;
> }
> finally {
> if( s != null ) try {s.close();} catch(SQLException
> ignore1) { }
> if(!committed ) try {c.rollback();}
> catch(SQLException ignore2)
> { }
> ConnectionGenerator.poolCheckin(c);
> }
>
> I really don't think you'd want to implement this sort of code in a
> .jsp...
>
===========================================================================
To unsubscribe: mailto [EMAIL PROTECTED] with body: "signoff JSP-INTEREST".
FAQs on JSP can be found at:
http://java.sun.com/products/jsp/faq.html
http://www.esperanto.org.nz/jsp/jspfaq.html
