Struts问题

[gmz]

package firstjsp;

import org.apache.struts.action.*;
import javax.servlet.http.*;

public class WelcomeAction extends Action {
public ActionForward perform(ActionMapping actionMapping, ActionForm actionForm, HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse) {
/**@todo: complete the business logic here, this is just a skeleton.*/
WelcomeActionForm welcomeActionForm = (WelcomeActionForm) actionForm;
throw new java.lang.UnsupportedOperationException("Method perform() not yet implemented.");
HttpSession /* 这里有问题，请问怎么解决 */ session = httpServletRequest.getSession(false);
String username=((WelcomeActionForm)actionForm).getUsername();
session.setAttribute("username",username);
return(actionMapping.findForward("welcome"));
}
}