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.
I'm sure there is a way of doing that since plugin developers would need to create project types. But I'm sure it is complicated and there are easier ways to accomplish what you are trying to do.
1) Create a project containing the proper classpath and jars. Every time, you want a new Struts project, make a copy of this project. 2) Download a plugin that supports Struts. You can do a search of this forum to find a few. I think one is free.