public String intercept(ActionInvocation invocation) throws Exception {
        // TODO Auto-generated method stub
        System.out.println("----------经过了拦截器---------------");
        ActionContext act = ActionContext.getContext();
        Cuserinfo uinfo = (Cuserinfo)act.getSession().get("user");
        if(uinfo == null){
            System.out.println("回话过时,请重新登录");
            act.put("message", "回话过时,请重新登录.");
            return "forward";
        }else{
            return invocation.invoke();
        }
        
    }

<global-results>
            <result name="forward">/forward.jsp</result>
        </global-results>