以下几种方式只有在已搭好的SpringMVC环境中,才能执行成功!
首先,写一个登陆页面和一个Bean类
 <%@ page language="java" contentType="text/html; charset=UTF-8"
pageEncoding="UTF-8"%>
<!DOCTYPE html>
<html>
 <head>
 <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
 <title>yyx博客后台登录</title>
</head>
<body>
 <form action="${pageContext.request.contextPath}/user/login.do"
    method="post">
    <table>
        <tr>
            <td>用户名:</td>
            <td><input type="text"  name="userName"></td>
        </tr>
        <tr>
            <td>密码:</td>
            <td><input type="password"  name="userPwd"></td>
        </tr>
        <tr>
            <td colspan="2"><input type="submit" value="登陆"></td>
        </tr>
    </table>
</form>
</body>
</html>

package com.yyx.model;
public class User {
private String userName;
private String userPwd;

public String getUserName() {
    return userName;
}

public void setUserName(String userName) {
    this.userName = userName;
}

public String getUserPwd() {
    return userPwd;
}

public void setUserPwd(String userPwd) {
    this.userPwd = userPwd;
}
 }

1、直接把表单的参数写在Controller相应的方法的形参中
package com.yyx.controller;

import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;

@Controller
@RequestMapping("/user")
public class UserController {
@RequestMapping("/login")
public String loginByUser(String userName, String userPwd) {
    System.out.println("userName is:" + userName);
    System.out.println("userPwd is:" + userPwd);
    return "success";
}
}
控制器中方法的形参String userName,String userPwd名称必须和登陆页面的name=“userName”,name="userPwd"相同

2.通过HttpServletRequest接收
package com.yyx.controller;

import javax.servlet.http.HttpServletRequest;

import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;

@Controller
@RequestMapping("/user")
public class UserController {
@RequestMapping("/login")
public String loginByUser(HttpServletRequest request) {
    String userName=request.getParameter("userName");
    String userPwd=request.getParameter("userPwd");
    System.out.println("userName is:" + userName);
    System.out.println("userPwd is:" + userPwd);
    return "success";
}
}
控制器中String userName=request.getParameter(“userName”);String userPwd=request.getParameter(“userPwd”);的参数名称必须和登陆页面的name=“userName”,name="userPwd"相同

3.通过一个bean来接收
package com.yyx.controller;

import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;

import com.yyx.model.User;

@Controller
@RequestMapping("/user")
public class UserController {
@RequestMapping("/login")
public String loginByUser(User user) {
    System.out.println("userName is:" + user.getUserName());
    System.out.println("userPwd is:" + user.getUserPwd());
    return "success";
}
}
登陆页面的name=“userName”,name="userPwd"必须和Bean类的属性名称相同

4.通过json数据接收
<%@ page language="java" contentType="text/html; charset=UTF-8"
pageEncoding="UTF-8"%>

<!DOCTYPE html>
 <html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<script type="text/javascript"
src="${pageContext.request.contextPath}/static/jquery-3.1.1.min.js"></script>
<title>yyx博客后台登录</title>
<script type="text/javascript">
$(document).ready(function() {
    $("#button_submit").click(function() {
        var name = $("#userName").val();
        var pwd = $("#userPwd").val();
        var user = {
            userName : name,
            userPwd : pwd
        };//拼装成json格式
        $.ajax({
            type : "POST",
            url : "${pageContext.request.contextPath}/user/login.do",
            data : user,
            success : function(data) {
                alert("成功");
            },
            error : function(e) {
                alert("出错:" + e);
            }
        });
    });
});
</script>
</head>
<body>
<form>
    <table>
        <tr>
            <td>用户名:</td>
            <td><input type="text" id="userName"></td>
        </tr>
        <tr>
            <td>密码:</td>
            <td><input type="password" id="userPwd"></td>
        </tr>
        <tr>
            <td colspan="2"><input type="button" id="button_submit"
                value="提交"></td>
        </tr>
    </table>
</form>
</body>
</html>

package com.yyx.controller;

import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;

import com.yyx.model.User;

@Controller
@RequestMapping("/user")
public class UserController {
@RequestMapping("/login")
public String loginByUser(User user) {
    System.out.println("userName is:" + user.getUserName());
    System.out.println("userPwd is:" + user.getUserPwd());
    return "success";
}
}
var user={userName:name,userPwd:pwd};//拼装成json格式 语句中userName,userPwd必须和Bean类中属性名称相同