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Connection Pooling in Servlets

Manal Sabri

Joined: Nov 24, 2000
Posts: 2
can anyone please explain me why connection pooling of database connections is done in servlets and exactly hw it is done .
thanks in advance ..
Mirko Froehlich
Ranch Hand

Joined: Aug 21, 2000
Posts: 114
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.
Ashwin Desai
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Joined: Jul 17, 2000
Posts: 124
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.
Matthew X. Brown
Ranch Hand

Joined: Nov 08, 2000
Posts: 165
There is some great source code for connection pooling- go to 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
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Joined: Nov 08, 2000
Posts: 165
BTW- the source code is based on a book entitled- Core Servlets and JavaServer Pages, by Marty Hall- its very good.
maha anna
Ranch Hand

Joined: Jan 31, 2000
Posts: 1467
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.
maha anna
Consider Paul's rocket mass heater.
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