1.创建一个springBoot项目

添加依赖

修改pom.xml，改mysql的版本，添加xml的扫描方式

        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <scope>runtime</scope>
            <version>5.1.47</version>
        </dependency>
        <dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>druid-spring-boot-starter</artifactId>
            <version>1.1.22</version>
        </dependency>

        <resources>
            <resource>
                <directory>src/main/java</directory>
                <includes>
                    <include>**/*.xml</include>
                </includes>
            </resource>
            <resource>
                <directory>src/main/resources</directory>
            </resource>
        </resources>

如果出现maven依赖报错，点击maven的刷新按钮

2.配置数据库账号密码

spring.datasource.type=com.alibaba.druid.pool.DruidDataSource
spring.datasource.username=root
spring.datasource.password=root
spring.datasource.url=jdbc:mysql://localhost:3306/java?useUnicode=true&characterEncoding=UTF-8

3.开启包扫描，创建mapper和model

package org.java.mybatis;

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

@SpringBootApplication
@MapperScan(basePackages = "org.java.mybatis.mapper")
public class MybatisApplication {

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

}

创建方法

package org.java.mybatis.mapper;

import org.java.mybatis.model.User;

import java.util.List;


public interface UserMapper {
     List<User>list();

}

创建实体类

package org.java.mybatis.model;

import java.io.Serializable;

public class User implements Serializable {

    private static final long serialVersionUID = 8596421348439484783L;
    private int id;
    private String userName;
    private String sex;

    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 getSex() {
        return sex;
    }

    public void setSex(String sex) {
        this.sex = sex;
    }
}

接下来是创建xml文件,先在idea里面创建一个xml模板

复制以下代码到模板中,更改名字，以及后缀，最后apply

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

然后新建mapper文件

更改以下内容

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

    <select id="list" resultType="org.java.mybatis.model.User">
        select * from user
    </select>
</mapper>

4.进行测试

package org.java.mybatis;

import org.java.mybatis.mapper.UserMapper;
import org.java.mybatis.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 MybatisApplicationTests {

    @Autowired
    UserMapper userMapper;

    @Test
    void contextLoads() {
        List<User> list = userMapper.list();
        System.out.println(list);
    }

}