<!-- 引入 myBatis，这是 MyBatis官方提供的适配 Spring Boot 的，而不是Spring Boot自己的-->
<dependency>
    <groupId>org.mybatis.spring.boot</groupId>
    <artifactId>mybatis-spring-boot-starter</artifactId>
    <version>2.1.0</version>
</dependency>

import lombok.AllArgsConstructor;
import lombok.Data;
import lombok.NoArgsConstructor;

@Data
@AllArgsConstructor
@NoArgsConstructor
public class User {

    private int id;
    private String name;
    private String pwd;

}

import org.apache.ibatis.annotations.Mapper;
import org.springframework.stereotype.Repository;
import ustc.wzh.pojo.User;

import java.util.List;

//@Mapper : 表示本类是一个 MyBatis 的 Mapper，等价于以前 Spring 整合 MyBatis 时的 Mapper 接口
@Mapper
@Repository
public interface UserMapper {

    //选择全部用户
    List<User> selectUser();
    //根据id选择用户
    User selectUserById(int id);
    //添加一个用户
    int addUser(User user);
    //修改一个用户
    int updateUser(User user);
    //根据id删除用户
    int deleteUser(int id);

}

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE mapper
        PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
        "http://mybatis.org/dtd/mybatis-3-mapper.dtd">

<mapper namespace="ustc.wzh.mapper.UserMapper">

    <select id="selectUser" resultType="User">
      select * from user
    </select>

    <select id="selectUserById" resultType="User">
        select * from user where id = #{id}
    </select>

    <insert id="addUser" parameterType="User">
        insert into user (id,name,pwd) values (#{id},#{name},#{pwd})
    </insert>

    <update id="updateUser" parameterType="User">
        update user set name=#{name},pwd=#{pwd} where id = #{id}
    </update>

    <delete id="deleteUser" parameterType="int">
        delete from user where id = #{id}
    </delete>
</mapper>

#指定myBatis的核心配置文件与Mapper映射文件
mybatis:
  mapper-locations: classpath:mybatis/mapper/*.xml
  # 注意：对应实体类的路径
  type-aliases-package: ustc.wzh.pojo

import com.alibaba.fastjson.JSON;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;
import ustc.wzh.mapper.UserMapper;
import ustc.wzh.pojo.User;

import java.util.List;

@RestController
@RequestMapping("/mybatis")
public class UserController {

    @Autowired
    private UserMapper userMapper;

    //选择全部用户
    @GetMapping("/selectUser")
    public String selectUser(){
        List<User> users = userMapper.selectUser();
        for (User user : users) {
            System.out.println(user);
        }

        return "mybatis-selectUser:"+JSON.toJSONString(users);
    }

    //根据id选择用户
    @GetMapping("/selectUserById")
    public String selectUserById(){
        User user = userMapper.selectUserById(1);
        System.out.println(user);
        return "mybatis-selectUserById:"+JSON.toJSONString(user);
    }

    //添加一个用户
    @GetMapping("/addUser")
    public String addUser(){
        User user = new User(5,"阿毛","456789");
        userMapper.addUser(user);
        return "mybatis-addUser:"+JSON.toJSONString(user);
    }

    //修改一个用户
    @GetMapping("/updateUser")
    public String updateUser(){
        User user = new User(5,"阿毛","421319");
        userMapper.updateUser(user);
        return "mybatis-updateUser:"+JSON.toJSONString(user);
    }

    //根据id删除用户
    @GetMapping("/deleteUser")
    public String deleteUser(){
        userMapper.deleteUser(5);
        return "mybatis-deleteUser:ok";
    }

}