Spring Vs Custom Contoller Servlet

arctictree

I wonder if someone could give me some advice.

I have written a J2EE application which has got fairly big over the years. I have one custom controller servlet which controls the interface between the web and business layer. This servlet has now got really big (about 200 if statements in the controller method). I have heard that I should really use Spring for this.

Could someone give me some really good arguments for changing my application to use spring instead? I mean, it actually works fine at the moment, its just a bit messy.

Thanks!

A