步骤一、配置pom.xml

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.6.5</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>
    <groupId>com.shen</groupId>
    <artifactId>springboot-mybatis</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>springboot-mybatis</name>
    <description>Demo project for Spring Boot</description>
    <properties>
        <java.version>1.8</java.version>
    </properties>
    <dependencies>
        <dependency>
            <groupId>org.mybatis.spring.boot</groupId>
            <artifactId>mybatis-spring-boot-starter</artifactId>
            <version>2.2.2</version>
        </dependency>

        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <scope>runtime</scope>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>

</project>

步骤二、实体类

package com.shen.springbootmybatis.model;

public class User {

    private int id;
    private String username;
    private String password;

    public User() {
    }

    public User(int id, String username, String password) {
        this.id = id;
        this.username = username;
        this.password = password;
    }

    public int getId() {
        return id;
    }

    public void setId(int id) {
        this.id = id;
    }

    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;
    }

    @Override
    public String toString() {
        return "user{" +
                "id=" + id +
                ", username='" + username + '\'' +
                ", password='" + password + '\'' +
                '}';
    }
}

步骤三、XxxMapper接口类

package com.shen.springbootmybatis.mapper;

import com.shen.springbootmybatis.model.User;
import org.apache.ibatis.annotations.Mapper;
import org.springframework.stereotype.Repository;

import java.util.List;

@Mapper
@Repository
public interface UserXmlMapper {

    public List<User> findAll();
}

步骤四、XxxMapper接口映射的XML

<?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="com.shen.springbootmybatis.mapper.UserXmlMapper">
    <resultMap id="returnType" type="com.shen.springbootmybatis.model.User">
        <id property="id" column="ID"/>
        <result property="username" column="USERNAME"/>
        <result property="password" column="PASSWORD"/>
    </resultMap>

    <select id="findAll" resultMap="returnType">
        select * from tb_user
    </select>
</mapper>

步骤五、application.yml

spring:
#  数据源信息配置
  datasource:
    url: jdbc:mysql://192.168.137.5:3306/dbtmp?serverTimezone=UTC
    username: root
    password: 123456
    driver-class-name: com.mysql.cj.jdbc.Driver

# mybatis
mybatis:
#  mapper 映射文件路径
  mapper-locations: classpath:mapper/*Mapper.xml
  type-aliases-package: com.shen.springbootmybatis.model
#  config-location: --指定mybatis核心配置文件

步骤六、单元测试

package com.shen.springbootmybatis;

import com.shen.springbootmybatis.mapper.UserMapper;
import com.shen.springbootmybatis.mapper.UserXmlMapper;
import com.shen.springbootmybatis.model.User;
import org.junit.jupiter.api.Test;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.context.SpringBootTest;

import java.util.List;

@SpringBootTest
class SpringbootMybatisApplicationTests {

    @Autowired
    private UserMapper userMapper;

    @Autowired
    private UserXmlMapper userXmlMapper;

    @Test
    public void testFindAll() {
        List<User> users = userMapper.findAll();
        System.out.println(users);
    }

    @Test
    public void testFindAllXml() {
        List<User> users = userXmlMapper.findAll();
        System.out.println(users);
    }

}