public void service(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {

        response.setContentType("text/html");
        String uri = request.getRequestURI();
        String action = uri.substring(uri.lastIndexOf("/") + 1, uri.lastIndexOf(".do"));
        if (action.equals("list")) {
//            MailUtil.sendMail("test", "testcontent", "289048093@qq.com");
            Scheduler.restartUserOperators();
//            request.setAttribute("users", Scheduler.getUsers().values());
            dispatcher("list.jsp", request, response);
            return;
        }
        if (action.equals("login")) {
            String username = request.getParameter("username");
            String randCode = request.getParameter("randCode");
            UserOperator uo = Scheduler.getUserOperators().get(username);
            if (uo == null) {
                redirect("list.jsp", response);
                return;
            }
            uo.login(randCode);
//            Scheduler.restartUserOperators();
            redirect("list.jsp", response);
            return;
        }
    }