Environment:
Tomcat 7
JNDI
Spring-MyBatis
No JTA - commons pooling only
Problem: Can't get the connection pooling to work as advertised. I can't find a single example of this that doesn't use a stand-alone Transaction manager or that doesn't put all the settings in the war, which makes JNDI pointless. I'm told that JTA is overkill for this application and that we should stick with commons pooling. That makes sense but I don't see a way to configure pooling, if we do it that way.
So... how do I configure connection pooling without putting the settings in the war file AND without using a stand-alone transaction manager? Can this be done without a full Java EE Application Server? We are just moving to Tomcat from another product which actually is full Java EE, so I am thinking this may be a Container vrs. Application server issue.
The weird part is that we can and have used JNDI but the pooling is definitely wrong.
Here is one example that probably works but why bother with JNDI if the settings are going to be in META-INF/context.xml?:
MyBatis JNDI Example
Even with context.xml, it's still a container level setting. But, it's a convenient way of deploying everything in a singe unit rather than having to create the connection pool before you deploy the WAR file.
JNDI is meant to keep your application configuration generic. If you take your WAR and deploy it in WebSphere, for example, it will ignore the context.xml file. But WebSphere will see that you have a JDNI resource-ref in your web.xml and walk you through creating the data source. Same idea as Tomcat, just a different way of doing it.
If you are 100% sure that this application will only run in Tomcat then you don't have to use JNDI. But, it will save you trouble later if you do move to another container.