mybatis官方文档连接：https://mybatis.org/mybatis-3/zh/getting-started.html

dome结构：

 数据库结构：

 项目代码：

UserDao.java

package dao;

import pojo.User;

import java.util.List;

public interface UserDao {
    List<User> getUserList();
}

UserMapper.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">
<!--namespace=绑定一个对应的Dao/Mapper接口-->
<mapper namespace="dao.UserDao">
    <select id="getUserList" resultType="pojo.User">
        select * from mybatis.user
    </select>

</mapper>

User.java

package pojo;

//实体类
public class User {
    int id;
    String name;
    String pwd;

    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 getPwd() {
        return pwd;
    }

    public void setPwd(String pwd) {
        this.pwd = pwd;
    }
}

MybatisUtils.java

package utils;

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 java.io.IOException;
import java.io.InputStream;

//sqlSessionFactory     sqlSession
public class MybatisUtils {

    private static SqlSessionFactory sqlSessionFactory;
    //使用Mybatis第一步，获取sqlSessionFactory对象
    static
    {
        String resource = "mybatis-config.xml";

        {
            try {
                InputStream inputStream = Resources.getResourceAsStream(resource);
                sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);
            } catch (IOException e) {
                e.printStackTrace();
            }
        }

    }
    //既然有了 SqlSessionFactory，顾名思义，我们可以从中获得 SqlSession 的实例。
    //SqlSession 提供了在数据库执行 SQL 命令所需的所有方法。你可以通过 SqlSession 实例来直接执行已映射的 SQL 语句
    public static SqlSession getSqlSession()
    {
        return sqlSessionFactory.openSession();
    }
}

mybatis-config.xml

<?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>
    <environments default="development">
        <environment id="development">
            <transactionManager type="JDBC"/>
            <dataSource type="POOLED">
                <property name="driver" value="com.mysql.jdbc.Driver"/>
                <property name="url" value="jdbc:mysql://localhost:3306/mybatis?useUnicode=true&amp;characterEncoding=utf-8&amp;zeroDateTimeBehavior=convertToNull&amp;serverTimezone=UTC
"/>
                <property name="username" value="root"/>
                <property name="password" value="123456"/>
            </dataSource>
        </environment>
    </environments>
<!--每一个mapper都要注意一次-->
    <mappers>
        <mapper resource="dao/UserMapper.xml"></mapper>
    </mappers>
</configuration>

UserDaoTest

package dao;

import org.apache.ibatis.session.SqlSession;
import org.junit.Test;
import pojo.User;
import utils.MybatisUtils;

import java.util.List;

public class UserDaoTest {
    @Test
    public  void test()
    {
        //获得SqlSession对象
        SqlSession sqlSession=MybatisUtils.getSqlSession();
        //执行Sql
        UserDao userDao=sqlSession.getMapper(UserDao.class);
        List<User> userList=userDao.getUserList();

        for(User user:userList)
        {
            System.out.println(user.getId());
        }
        //关闭SqlSession
        sqlSession.close();
    }
}

数据库内容：

 测试结果图：

体会：

测试代码调用MybatisUtils.java文件，MybatisUtils.java文件调用mybatis-config.xml配置文件，测试文件再利用所返回的SqlSession调用UserDao接口文件，运行UserMapper.xml文件中的sql语句。经学习，了解到mybatis可以很好的将文件解耦，对程序的维护有利。

学习一项新的技术，他的官方文档很重要。