MyBatis 是一款优秀的持久层框架，它支持自定义 SQL、存储过程以及高级映射。MyBatis 免除了几乎所有的 JDBC 代码以及设置参数和获取结果集的工作。MyBatis 可以通过简单的 XML 或注解来配置和映射原始类型、接口和 Java POJO（Plain Old Java Objects，普通老式 Java 对象）为数据库中的记录。

第一步、创建数据库

CREATE DATABASE `mybatis_db`;
USE `mybatis_db`;
CREATE TABLE `user` (
`id` int(11) NOT NULL auto_increment,
`username` varchar(32) NOT NULL COMMENT '用户名称',
`birthday` datetime default NULL COMMENT '生日',
`sex` char(1) default NULL COMMENT '性别',
`address` varchar(256) default NULL COMMENT '地址',
PRIMARY KEY (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;
-- insert....
insert into `user`(`id`,`username`,`birthday`,`sex`,`address`) values (1,'子
慕','2020-11-11 00:00:00','男','北京海淀'),(2,'应颠','2020-12-12 00:00:00','男','北
京海淀');

第二步、新建maven项目，导入MyBatis的坐标和其他相关坐标

<!--mybatis坐标-->
<dependency>
<groupId>org.mybatis</groupId>
<artifactId>mybatis</artifactId>
<version>3.5.4</version>
</dependency>
<!--mysql驱动坐标-->
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
<version>5.1.6</version>
<scope>runtime</scope>
</dependency>
<!--单元测试坐标-->
<dependency>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
<version>4.12</version>
<scope>test</scope>
</dependency>

第三步、编写User实体类

package com.xh.pojo;

public class User {
    private int id;
    private String username;
    private String birthday;
    private String sex;
    private String address;

    @Override
    public String toString() {
        return "User{" +
                "id=" + id +
                ", username='" + username + '\'' +
                ", birthday='" + birthday + '\'' +
                ", sex='" + sex + '\'' +
                ", address='" + address + '\'' +
                '}';
    }

    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 getBirthday() {
        return birthday;
    }

    public void setBirthday(String birthday) {
        this.birthday = birthday;
    }

    public String getSex() {
        return sex;
    }

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

    public String getAddress() {
        return address;
    }

    public void setAddress(String address) {
        this.address = address;
    }
}

第四步、编写UserMapper映射文件

<?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="UserMapper">
<!--  id标识  namespace命名空间：与id属性构成唯一标识 nnamespace.id user.id-->
<!--    resultType:返回结果类型 自动映射封装 要封装的实体的全路径-->
    <select id="findAll" resultType="com.xh.pojo.User">
        select * from user
    </select>
</mapper>

第五步、编写MyBatis核心文件

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE configuration
        PUBLIC "-//mybatis.org//DTD Config 3.0//EN"
        "http://mybatis.org/dtd/mybatis-3-config.dtd">
<configuration>
    <!--环境配置-->
    <environments default="mysql">
        <!--使用MySQL环境-->
        <environment id="mysql">
            <!--使用JDBC类型事务管理器-->
            <transactionManager type="JDBC"></transactionManager>
            <!--使用连接池-->
            <dataSource type="POOLED">
                <property name="driver" value="com.mysql.jdbc.Driver"></property>
                <property name="url" value="jdbc:mysql:///mybatis_db"></property>
                <property name="username" value="root"></property>
                <property name="password" value="root"></property>
            </dataSource>
        </environment>
    </environments>
    <!--加载映射配置-->
    <mappers>
        <mapper resource="mapper/UserMapper.xml"></mapper>
    </mappers>
    </configuration>

第六步、编写测试类

package com.xh.Test;

import com.xh.pojo.User;
import org.apache.ibatis.io.Resources;
import org.apache.ibatis.session.SqlSession;
import org.apache.ibatis.session.SqlSessionFactory;
import org.apache.ibatis.session.SqlSessionFactoryBuilder;
import org.junit.Test;

import java.io.IOException;
import java.io.InputStream;
import java.util.List;

public class MybatiseTest {
    @Test
    public void mybatisQuickStart() throws IOException {
        //1.加载核心配置文件
        InputStream resourceAsStream = Resources.getResourceAsStream("sqlMappConfig.xml");
        //2.获取sqlSessionFactory工厂对象
        SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(resourceAsStream);
        // 3.获取sqlSession会话对象
        SqlSession sqlSession = sqlSessionFactory.openSession();
        //4.执行sql 参数：statementid：namespace.id组成
        List<User> users = sqlSession.selectList("UserMapper.findAll");
        for (User user : users) {
            System.out.println(user);
        }
        sqlSession.close();
    }
}