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.
In servlets , HTTPServletRequest's getParameterNames() and getParameterMap() would give you the expected parameters list.
For Struts , you can access HTTPServletRequest as well , so that should be acheivable. anyways wait for Struts experts comments.