java手機驗證碼5分鍾有效，利用session

 final HttpSession httpSession=request.getSession();
       final HttpSession httpSession=request.getSession();
    httpSession.setAttribute(Constants.YXCODE1, code1);
        try {
           
            //TimerTask實現5分鍾后從session中刪除checkCode
            final Timer timer=new Timer();
            timer.schedule(new TimerTask() {
                @Override
                public void run() {
                   String yxcode1 =  (String) httpSession.getAttribute(Constants.YXCODE1);
          if(StringUtils.isNotEmpty(yxcode1)){
              //確保清除不出錯
            httpSession.removeAttribute(Constants.YXCODE1);
          }
                    timer.cancel();
                }
            },5*60*1000);
        } catch (Exception e) {
            e.printStackTrace();
        }