This week's book giveaway is in the OO, Patterns, UML and Refactoring forum. We're giving away four copies of Refactoring for Software Design Smells: Managing Technical Debt and have Girish Suryanarayana, Ganesh Samarthyam & Tushar Sharma 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.