missing type javax.servlet.http.HttpServletRequest

Hi All,

I have imported a par file.its giving an error after build---

Error The project was not built since its classpath is incomplete. Cannot find the class file for javax.servlet.http.HttpServletRequest. Fix the classpath then try rebuilding this project.

Error This compilation unit indirectly references the missing type javax.servlet.http.HttpServletRequest (typically some required class file is referencing a type outside the classpath)

Please help me fix this error ....from where can i get the missing..type javax.servlet.http.HttpServletRequest