Struts is a common MVC solution that has been proven in many Java projects. If you need to use Struts, here is an article that is pretty useful to get started on Struts. Included is an overview of what Struts is and how Struts works, Struts actions, form, common tags used in Struts, Tiles, and how to use JBuilder for Struts development.
This article gives an example of a Struts/Ajax solution for updating display data based on a select box without having to refresh the whole page. This is an alternative to writing Javascript straight on to the page that manipulates the DOM.