Question

I have a single .war file with my web-application. The root of the problem is that I want to keep one .war file for all customers (which have different environment). For this I should keep different versions of libraries in .war and decide which of them to use while deployment.

For example:

First customer have oracle 10, the second one have oracle 11. I want keep both ojdbc.jar files in my war, and choose which of them to use according to some parameter in properties file.

One solution to solve this problem is writing my own ClassLoader, which will not load useless files(as shown here: https://serverfault.com/questions/317901/tomcat-possible-to-exclude-jars-during-app-deployment).

The problem is that our ClassLoader class should be into “tomcat\lib” directory. This do installation of my application is more complex.

Maybe there are another ways how to solve this problem? It will be great to do it programmatically inside my application, using reflection or something else.

Thanks for help!

Answer 1

IMHO the best practice for the example you give (database driver) is to provide a datasource through tomcat. This implies that the database driver jar needs to be in the global classpath (tomcat/lib). This would also keep your intent to have the same .war file for all customers – when you update this, you only need to provide an identical file for all users.

In the case of a database connection, you’ll most likely need a customized database for each customer anyway – providing this as a datasource through tomcat makes it necessary to configure it once (on first installation), but you won’t need to worry about it afterwards.

If database drivers are not your only problem, please update your question with more examples of differing environments/jars.