This week's book giveaway is in the OCPJP forum. We're giving away four copies of OCA/OCP Java SE 7 Programmer I & II Study Guide and have Kathy Sierra & Bert Bates on-line! See this thread for details.
You can create a subclass of the servlet with no implementation and define it there. I'd prefer to keep both definitions in the web.xml. It is clearer to show how many instances of the servlet with different parameters there are.