Connection Pooling in Servlets

[Manal Sabri]

can anyone please explain me why connection pooling of database connections is done in servlets and exactly hw it is done .
thanks in advance ..
manal

[Mirko Froehlich]

If you do a lot of database queries, opening and closing a new connection every time is very inefficient. Therefore, you want to use connection pooling. Basically, you will need to write a Java class to represent the connection pool, possibly as a singleton. When this class is instantiated, it opens a specified number of database connections. Whenever your JSP pages or servlets need to open a connection, they request it from the connection pool class instead of creating a new one. The pool class then checks if it still has an open connection and returns it, or it blocks and waits until a connection is available again.
-Mirko

[Ashwin Desai]

An addition to the above answer,
Connection Pool is not limited to be used for servlets. This can be used by any Database accessing servers. In fact, a similar kind of notion called as an Object Pool is also widely used to recycle the objects coz object creation time is also substantial.
Ashwin.

[Matthew X. Brown]

There is some great source code for connection pooling- go to www.coreservlets.com and go to the 18th chapter-has an example and case study- I went through it and understand connection pooling much better than I did prior to it.I believe it might even implement a singleton pattern -although I don't remember exactly.

[Matthew X. Brown]

BTW- the source code is based on a book entitled- Core Servlets and JavaServer Pages, by Marty Hall- its very good.

[maha anna]

Yes. I also use it. But the author overlooked to close the Statements and RedulstSet in one method. i had to fix it. Other than this the class defn is good.
regds
maha anna