How to configure Spring to call an image serving servlet from the dispatcher servlet?

I've written the code for a servlet to serve images in my app from a url such as:

/imgsrv?imgid=12345

So this would be one additional servlet in the app besides the Dispatcher servlet.

The problem is, I don't know how do you configu开发者_运维问答re Spring to call this new servlet from the Dispatcher servlet?

Can you make it clear that why you should call the new servlet from the Dispatcher servlet, what not just add a new servlet?