网页版Java（Spring/Spring Boot/Spring MVC）五子棋项目（二）前后端实现用户的登录和注册功能【用户模块】

在用户模块我们要清楚要完成的任务

一、MyBatis后端操作数据库

1. 需要在数据库创建用户数据库

1. 用户id

2. 用户名

3. 密码

4. 天梯积分

5. 总场数

6. 获胜场数

create database if not exists java_gobang;

use java_gobang;

drop table if exists user;
create table user (
    userId int primary key auto_increment,
    username varchar(50) unique,
    password varchar(50),
    score int,       -- 天梯积分
    totalCount int,  -- 比赛总场数
    winCount int     -- 获胜场数
);

insert into user values(null, 'zhangsan', '123', 1000, 0, 0);
insert into user values(null, 'lisi', '123', 1000, 0, 0);
insert into user values(null, 'wangwu', '123', 1000, 0, 0);

2. 创建用户类User

和数据库的数据一一对应

package com.example.java_gobang.model;

public class User {
    private int userId;
    private String username;
    private String password;
    private int score;
    private int totalCount;
    private int winCount;

    public int getUserId() {
        return userId;
    }

    public void setUserId(int userId) {
        this.userId = userId;
    }

    public String getUsername() {
        return username;
    }

    public void setUsername(String username) {
        this.username = username;
    }

    public String getPassword() {
        return password;
    }

    public void setPassword(String password) {
        this.password = password;
    }

    public int getScore() {
        return score;
    }

    public void setScore(int score) {
        this.score = score;
    }

    public int getTotalCount() {
        return totalCount;
    }

    public void setTotalCount(int totalCount) {
        this.totalCount = totalCount;
    }

    public int getWinCount() {
        return winCount;
    }

    public void setWinCount(int winCount) {
        this.winCount = winCount;
    }
}

3. 用MyBatis操作数据库

1. 连接数据库（application.yml连接数据库）

这个可以直接赋值代码

spring:
  datasource:
    url: jdbc:mysql://127.0.0.1:3306/java_gobang?characterEncoding=utf8&useSSL=false&serverTimezone=GMT%2B8
    username: root
    password: 123456
    driver-class-name: com.mysql.cj.jdbc.Driver

mybatis:
  mapper-locations: classpath:mapper/**Mapper.xml

logging:
  pattern:
    console: "[%-5level] - %msg%n"

2. 创建UserMapper的Java接口（interface UserMapper）

创建接口，在UserMapper.xml实现

在model中创建

需要实现@Mapper注释

package com.example.java_gobang.model;

import org.apache.ibatis.annotations.Mapper;

@Mapper
public interface UserMapper {
    // 往数据库里插入一个用户. 用于注册功能.
    void insert(User user);

    // 根据用户名, 来查询用户的详细信息. 用于登录功能
    User selectByName(String username);

    // 总比赛场数 + 1, 获胜场数 + 1, 天梯分数 + 30
    void userWin(int userId);

    // 总比赛场数 + 1, 获胜场数 不变, 天梯分数 - 30
    void userLose(int userId);
}

3. 创建UserMapper.xml 实现数据库操作

实现具体数据库操作

利用标签

mapper标签地址要对应好

不同操作 标签不同

DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN" "http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<mapper namespace="com.example.java_gobang.model.UserMapper">
    <insert id="insert">
        insert into user values(null, #{username}, #{password}, 1000, 0, 0);
    insert>

    <select id="selectByName" resultType="com.example.java_gobang.model.User">
        select * from user where username = #{username};
    select>
    
    <update id="userWin">
        update user set totalCount = totalCount + 1, winCount = winCount + 1, score = score + 30
        where userId = #{userId}
    update>
    
    <update id="userLose">
        update user set totalCount = totalCount + 1, score = score - 30
        where userId = #{userId}
    update>
mapper>

二、约定前后端接口

1. 登录接口

前端发送post请求，具体内容是直接对应的

所以后端的参数也是对应的，然后后端返回一个用户类

1. 后端通过前端传的用户名，查询数据库

2. 如果数据库为空，返回一个新的 用户类

3. 否则，把Session置为true

4. 然后返回用户类

@PostMapping("/login")
@ResponseBody
public Object login(String username, String password, HttpServletRequest req) {
    // 关键操作, 就是根据 username 去数据库中进行查询.
    // 如果能找到匹配的用户, 并且密码也一致, 就认为登录成功
    User user = userMapper.selectByName(username);
    System.out.println("[login] username=" + username);
    if (user == null || !user.getPassword().equals(password)) {
        // 登录失败
        System.out.println("登录失败!");
        return new User();
    }
    HttpSession httpSession = req.getSession(true);
    httpSession.setAttribute("user", user);
    return user;
}

2. 注册接口

前端POST请求，参数是一一对应

后端参数接受一个一一对应

1. 创建一个User类

2. 调用userMapper插入

如果创建重复 则抛出异常 返回一个新的User

    @PostMapping("/register")
    @ResponseBody
    public Object register(String username, String password) {
        try {
            User user = new User();
            user.setUsername(username);
            user.setPassword(password);
            userMapper.insert(user);
            return user;
        } catch (org.springframework.dao.DuplicateKeyException e) {
            User user = new User();
            return user;
        }
    }

3. 从服务器获取当前登录的信息

前端GET请求

后端

1. 判断用户是否Session中

2. 查询数据库 返回对应类

如果没有在则返回一个新的user

@GetMapping("/userInfo")
@ResponseBody
public Object getUserInfo(HttpServletRequest req) {
    try {
        HttpSession httpSession = req.getSession(false);
        User user = (User) httpSession.getAttribute("user");
        // 拿着这个 user 对象, 去数据库中找, 找到最新的数据
        User newUser = userMapper.selectByName(user.getUsername());
        return newUser;
    } catch (NullPointerException e) {
        return new User();
    }
}

4. UserAPI

package com.example.java_gobang.api;

import com.example.java_gobang.model.User;
import com.example.java_gobang.model.UserMapper;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.ResponseBody;
import org.springframework.web.bind.annotation.RestController;

import javax.annotation.Resource;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpSession;

@RestController
public class UserAPI {

    @Resource
    private UserMapper userMapper;

    @PostMapping("/login")
    @ResponseBody
    public Object login(String username, String password, HttpServletRequest req) {
        // 关键操作, 就是根据 username 去数据库中进行查询.
        // 如果能找到匹配的用户, 并且密码也一致, 就认为登录成功
        User user = userMapper.selectByName(username);
        System.out.println("[login] username=" + username);
        if (user == null || !user.getPassword().equals(password)) {
            // 登录失败
            System.out.println("登录失败!");
            return new User();
        }
        HttpSession httpSession = req.getSession(true);
        httpSession.setAttribute("user", user);
        return user;
    }

    @PostMapping("/register")
    @ResponseBody
    public Object register(String username, String password) {
        try {
            User user = new User();
            user.setUsername(username);
            user.setPassword(password);
            userMapper.insert(user);
            return user;
        } catch (org.springframework.dao.DuplicateKeyException e) {
            User user = new User();
            return user;
        }
    }

    @GetMapping("/userInfo")
    @ResponseBody
    public Object getUserInfo(HttpServletRequest req) {
        try {
            HttpSession httpSession = req.getSession(false);
            User user = (User) httpSession.getAttribute("user");
            // 拿着这个 user 对象, 去数据库中找, 找到最新的数据
            User newUser = userMapper.selectByName(user.getUsername());
            return newUser;
        } catch (NullPointerException e) {
            return new User();
        }
    }
}

三、实现前端页面

1. 登录页面

DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>登录title>

    <link rel="stylesheet" href="css/common.css">
    <link rel="stylesheet" href="css/login.css">
head>
<body>
    <div class="nav">
        五子棋对战
    div>
    <div class="login-container">
        
        <div class="login-dialog">
            
            <h3>登录h3>
            
            <div class="row">
                <span>用户名span>
                <input type="text" id="username">
            div>
            
            <div class="row">
                <span>密码span>
                <input type="password" id="password">
            div>
            
            <div class="row">
                <button id="submit">提交button>
            div>
        div>

    div>

    <script src="./js/jquery.min.js">script>
    <script>
        let usernameInput = document.querySelector('#username');
        let passwordInput = document.querySelector('#password');
        let submitButton = document.querySelector('#submit');
        submitButton.onclick = function() {
            $.ajax({
                type: 'post',
                url: '/login',
                data: {
                    username: usernameInput.value,
                    password: passwordInput.value,
                },
                success: function(body) {
                    // 请求执行成功之后的回调函数
                    // 判定当前是否登录成功~
                    // 如果登录成功, 服务器会返回当前的 User 对象. 
                    // 如果登录失败, 服务器会返回一个空的 User 对象. 
                    if (body && body.userId > 0) {
                        // 登录成功
                        alert("登录成功!");
                        // 重定向跳转到 "游戏大厅页面".
                        location.assign('/game_hall.html');
                    } else {
                        alert("登录失败!");
                    }
                },
                error: function() {
                    // 请求执行失败之后的回调函数
                    alert("登录失败!");
                }
            });
        }
    script>
body>
html>

2. 注册页面

DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>注册title>
    <link rel="stylesheet" href="css/common.css">
    <link rel="stylesheet" href="css/login.css">
head>
<body>
    <div class="nav">
        五子棋对战
    div>
    <div class="login-container">
        
        <div class="login-dialog">
            
            <h3>注册h3>
            
            <div class="row">
                <span>用户名span>
                <input type="text" id="username">
            div>
            
            <div class="row">
                <span>密码span>
                <input type="password" id="password">
            div>
            
            <div class="row">
                <button id="submit">提交button>
            div>
        div>
    div> 

    <script src="js/jquery.min.js">script>
    <script>
        let usernameInput = document.querySelector('#username');
        let passwordInput = document.querySelector('#password');
        let submitButton = document.querySelector('#submit');
        submitButton.onclick = function() {
            $.ajax({
                type: 'post',
                url: '/register',
                data: {
                    username: usernameInput.value,
                    password: passwordInput.value,
                },
                success: function(body) {
                    // 如果注册成功, 就会返回一个新注册好的用户对象. 
                    if (body && body.username) {
                        // 注册成功!
                        alert("注册成功!")
                        location.assign('/login.html');
                    } else {
                        alert("注册失败!");
                    }
                }, 
                error: function() {
                    alert("注册失败!");
                }
            });
        }

    script>
body>
html>