request.getparamater在春天没有工作mvc

Question

request.getparameter在我的spring mvc中不工作我在下面使用html5是代码。

我试过在html中的text属性中添加名称，但它没有用。

package com.springmvc.controller;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.springframework.web.servlet.ModelAndView;
import org.springframework.web.servlet.mvc.Controller;


public class HelloWorldController implements Controller {

    @Override
    public ModelAndView handleRequest(HttpServletRequest req,
            HttpServletResponse res) throws Exception {

        System.out.println("***************");
    String userName =   req.getParameter("userName");
    String user =   req.getParameter("user");
    String nameCheck = req.getParameter("Username");
        ModelAndView mv = new ModelAndView("Sucess");
        return mv;
    }

}



  <input type="text" placeholder="Username" />
      <input type="password" placeholder="Password"/>
      <input type="email" placeholder="Email Address"/>
      <input type="tel" placeholder="Phone Number"/>
      <button>Register</button>