jsp 防止表单多次提交

1：首先java 后台代码生成一个token,然后保存到jsp 页面的一个隐藏控件并且保存到set session中

 */
    @RequestMapping("/yuDengJi")
    public String registrationAdd(HttpSession session, HttpServletResponse response, Model model, HttpServletRequest request,String exhiId,String canGuanId,String ispay,String type,String hangYe) {
        YuDengJi rsEx = new YuDengJi();
        rsEx.setExhiId(exhiId);//展览ID
        rsEx.setType(type);//类型(0参展团1参观团,2标准展位,3门票)
        
        model.addAttribute("exhiId", exhiId);//展馆ID
        model.addAttribute("canGuanId",canGuanId);//参观ID
        model.addAttribute("ispay",ispay);//参观团详细页面意向登记只显示参观
        model.addAttribute("hangYe", hangYe);//行业id
        
        model.addAttribute("tyep", type);//类型(0参展团1参观团,2标准展位,3门票)
        model.addAttribute("countYuDengJi", yuDengJiService.getCountYuDengJi(rsEx));//已经登记的参展或参观的个数
        String token = UUID.randomUUID().toString();//生成token 然后保存到jsp 页面的隐藏控件
        session.setAttribute("yudengjiToken", token);
        model.addAttribute("token", token);
    
        return "modules/yudengji/addYuDengJi";
    }

2：当用户提交表单时到后台Controller 类保存方法进行判断，当token 等于null 时 或者 隐藏控件的token 值 不等于session 的token 值就判断操作为多次提交表单

    @ResponseBody
    @RequestMapping("/yuDengJi/saveExhibitors")
    public String saveRegistration(HttpSession session, HttpServletResponse response, Model model, HttpServletRequest request,String type,String hangYe,String token) {
        YuDengJi rsEx = new YuDengJi();
        rsEx.setCompanyName(request.getParameter("companyName").trim());// 公司名称
        rsEx.setType(type);// 类型
        rsEx.setCanZhanMianJi(Double.parseDouble(request.getParameter("canZhanMianJi").trim()));// 意向参展面积
        rsEx.setCanZhanYuSuan(Double.parseDouble(request.getParameter("canZhanYuSuan").trim()));//参展预算
        rsEx.setName(request.getParameter("name").trim());// 联系人姓名
        rsEx.setPhone(request.getParameter("phone").trim());// 联系人手机号码
        rsEx.setMail(request.getParameter("mail").trim());// 邮箱
        rsEx.setKaoChaDi(request.getParameter("kaoChaDi").trim());// 意向考察目的地
        String exhiId = request.getParameter("exhiId").trim();
        rsEx.setExhiId(exhiId);//展览ID
        rsEx.setHangYe(hangYe);//关联行业
        
        Account account = (Account)session.getAttribute(Constants.ACCOUNT);
        String accountId = account.getId();
        if(!"".equals(accountId) && accountId !=null){//用户ID
            rsEx.setAccountId(Integer.parseInt(accountId));
        }
        try {
            String yudengjiToken = (String)session.getAttribute("yudengjiToken");
            if(yudengjiToken == null || !yudengjiToken.equals(token)){
                
            }else{
                yuDengJiService.save(rsEx);
                session.removeAttribute("yudengjiToken");
            }
            
               
            return "ok";
            /*String ulr  = "redirect:" + frontPath + "/exhi/product-"+exhiId+urlSuffix;
            System.out.println("ulr>>>>"+ulr);
            return "redirect:" + frontPath + "/exhi/product-"+exhiId+urlSuffix;*/
        } catch (Exception e) {
            e.printStackTrace();
            return "no";
        }
    }

3：用完后记得从session 中 remove 掉token

session.removeAttribute("yudengjiToken");