First of all it sounds like you're heading towards an XML solution without a clear need for it. Make sure you need it before you use it!
There are probably multiple ways to do it, but for ease of use I like
castor. It is object-centric, but provides both object to database and object to xml mappings. Therefore you need to load data as objects then convert to XML rather than going directly to XML, but it's easy to use and maintain.
Dave