1. 第一步，新建Project

把application.properties改成application.yml

 application.yml的内容：url?后面参数很关键

# 应用服务 WEB 访问端口

mybatis:
  mapper-locations: classpath:mapper/*.xml
  type-aliases-package: com.example.demo.bean
spring:
  datasource:
    name: testdb
    password: 123456
    username: root
    url: jdbc:mysql://localhost:3306/testdb?useUnicode=true&characterEncoding=UTF-8&serverTimezone=Asia/Shanghai
server:
  port: 8080

创建文件后的目录树：

pom.xml 的dependencies

    
        org.springframework.boot
        spring-boot-starter-web
    
    
        org.mybatis.spring.boot
        mybatis-spring-boot-starter
        2.1.4
    
    
        mysql
        mysql-connector-java
        runtime
    
    
        org.springframework.boot
        spring-boot-starter-test
        test
    
    
        junit
        junit
    

 UserBean 代码：

package com.example.demo.bean;

public class UserBean {
    private int ID;
    private String Name;
    private String Password;
    public int getID(){
        return ID;
    }
    public void setID(int ID){
        this.ID=ID;
    }
    public String getName(){
        return Name;
    }
    public void setName(String name){
        this.Name=name;
    }
    public String getPassword(){
        return Password;
    }
    public void setPassword(String password){
        this.Password =password;
    }

}

LoginController 代码：

package com.example.demo.controller;


import com.example.demo.bean.UserBean;
import com.example.demo.service.UserService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;

@Controller
public class LoginController {
    @Autowired
    UserService userService;

    @RequestMapping("/login")
    public String show(){
        return "login";
    }

    @RequestMapping(value="/loginIn",method = RequestMethod.POST)
    public String login(String name,String password){
        UserBean userBean=userService.loginIn(name,password);
        if(userBean!=null){
            return "success";
        }else{
            return "error";
        }
    }
}

UserMapper 代码：

package com.example.demo.mapper;

import com.example.demo.bean.UserBean;

public interface UserMapper {
    UserBean getInfo(String name,String password);
}

UserService 代码：

package com.example.demo.service;

import com.example.demo.bean.UserBean;

public interface UserService {
    UserBean loginIn(String name,String password);
}

UserServiceImpl 代码：

package com.example.demo.serviceImpl;

import com.example.demo.bean.UserBean;
import com.example.demo.mapper.UserMapper;
import com.example.demo.service.UserService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;

@Service
public class UserServiceImpl  implements UserService {

    @Autowired
    private   UserMapper userMapper;

    @Override
    public UserBean loginIn(String name,String password){
        return userMapper.getInfo(name,password);
    }
}

DemoApplication 代码：

package com.example.demo;

import org.mybatis.spring.annotation.MapperScan;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;

@SpringBootApplication
@MapperScan("com.example.demo.mapper")
public class DemoApplication {

    public static void main(String[] args) {
        SpringApplication.run(DemoApplication.class, args);
    }

}

UserMapper.xml 内容：

<?xml version="1.0" encoding="UTF-8"?>



    
        SELECT * FROM T_User WHERE name = #{name} AND password = #{password}
    



error.html  内容：

    
    


登录失败!




login.html 内容：

    
    



    账号：

    密码：

    

success.html 内容：

    
    


登录成功!

TestApplicationTest 的代码：

package com.example.demo;

import com.example.demo.bean.UserBean;
import com.example.demo.service.UserService;
import org.junit.jupiter.api.Test;
import org.junit.runner.RunWith;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.context.SpringBootTest;
import org.springframework.test.context.junit4.SpringRunner;

@RunWith(SpringRunner.class)
@SpringBootTest
class TestApplicationTests {

    @Autowired
    UserService userService;

    @Test
    public void contextLoads() {
        UserBean userBean=userService.loginIn("a","a");
        System.out.println("该用户ID为：");
        System.out.println(userBean.getID());
    }

}