@RequestMapping(value = "/logincheck" , method = RequestMethod.POST)
public String login(HttpServletResponse response,
                    @RequestParam(value = "UserName",required = true) String UserName,
                    @RequestParam(value = "PassWord",required = true) String PassWord){
    System.out.println(response.getHeaderNames()+"hhhh");
    UserDemo userDemo = new UserDemo();
    userDemo.setUserName(UserName);
    userDemo.setPassWord(PassWord);
    if(loginService.login(userDemo,response).equals("SUCCESS")){
        return "UserOne";
    }
    return "login";
}

里面response为什么是空值