I have a project now to use hibernate, the scene is following:
(1) I have a thread pool to manage threads for business handling.
(2) In every thread, it maybe access several datasources(two or three database servers)
(3) To every datasource, thread maybe access to the several tables.

I study the ThreadLocal sample (in document 42.html) and several other examples, but I have some questions:
(1) when should i invoke the method closeSession? (in these examples, I can find nowhere to invoke this method.)
(2) Do you have some better ways to be fit for my situation?Thanks.
(3) In a thread, how can i manage several datasource?

Thanks firstly.

At the end of each Unit of Work. Which is most cases is the end of the transaction.


No - sounds like SLSB but your doing the work for yourself. Just don't
use the same session in different threads. You avoid this with ThreadLocal.


You need to create multiple SessionFactories, eg, One for each different datasource.

David, thanks for your reply!

Must i close the session at the end of work? why those examples do no close the Session? are they wrong?

What examples? The document you mention shows some possible ways to implement the ThreadLocal pattern. There were no examples of how to utilize these impls.

As David mentioned, you're setup is very much like session beans. In a session bean setup, typically session beans control the unit-of-work or use-case. In fact, most of the time a session bean method corresponds to exactly to a use-case. So generally the session beans "prime" the thread local object prior to making the calls into the layer controlling Hibernate access (DAOs or whatever). After all Hibernate access is complete to fulfill the use-case the session bean closes the hibernate session.

So basically, wherever you logically perceive the business logic controller in your system, that layer should control the opening/closing of the Hibernate sessions.


You should to ensure proper transaction isolation.

Thanks Steve and David!

I will try as you say! thanks again!