This week's book giveaway is in the OCAJP 8 forum. We're giving away four copies of OCA Java SE 8 Programmer I Study Guide and have Edward Finegan & Robert Liguori on-line! See this thread for details.
The Action class which you are extending has a getServlet() method that allows you to get a reference to the ActionServlet instance. From there, you can get an init parameter in the same way you would with any servlet (getServletConfig().getInitParameter("xyz")).