1.引入相应的jar 包

<dependency>
   <groupId>org.mybatis</groupId>
   <artifactId>mybatis</artifactId>
   <version>3.5.2</version>
</dependency>
<dependency>
   <groupId>mysql</groupId>
   <artifactId>mysql-connector-java</artifactId>
   <version>5.1.47</version>
</dependency>

2.编写Mybatis核心配置文件·

1.路径在 项目的 resources
<?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/day2?useSSL=true&amp;useUnicode=true&amp;characterEncoding=utf8"/>
                <property name="username" value="root"/>
                <property name="password" value="123456789"/>
            </dataSource>
        </environment>
    </environments>
//每个Mapper 都需要注册到核心配置文件中
    <mappers>
        <mapper resource="com/example/dao/UserMapper.xml"/>
    </mappers>
</configuration>

mybatis 核心文件·配置.JPG

3.编写MyBatis 工具类

工具类放在utils 包下  
package com.example.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 javax.annotation.Resource;
import java.io.IOException;
import java.io.InputStream;

public class MybatisUtils {
    private static  SqlSessionFactory sqlSessionFactory;
    static {


        try{
            //使用mybatis  第一步  获取sqlsessionFactory  对象
            String resource="mybatis-config.xml";
            InputStream inputStream= Resources.getResourceAsStream(resource);
            sqlSessionFactory=new SqlSessionFactoryBuilder().build(inputStream);
        }catch (IOException e){
            e.printStackTrace();
        }
        //既然有了sqlsessionFactory     获取 sqlsession实例
        //sqlsession  完全面向数据库执行sql 命令

    }

    public  static SqlSession  getSqlSession(){
        SqlSession   sqlSession= sqlSessionFactory.openSession();
        return sqlSession;
    }




}

4.编写实体

package com.example.entity;

public class User {

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

    public User() {
    }

    public User(int id, String name, String pwd) {
        this.id = id;
        this.name = name;
        this.pwd = 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;
    }

    @Override
    public String toString() {
        return "User{" +
                "id=" + id +
                ", name='" + name + '\'' +
                ", pwd='" + pwd + '\'' +
                '}';
    }
}

5.编写Mapper 接口类/UserDao

package com.example.dao;

import com.example.entity.User;

import java.util.List;

public interface UserDao {

    List<User> getUserList();


}

6.编写Mapper.xml 配置文件

namespace  不能写错
<?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  绑定一个对于的Dao/MAPPER 接口-->
<mapper namespace="com.example.dao.UserDao">
    <!--id对应方法名    resultType /resultMap 经常用      resultType   对应实体·-->
        <select id="getUserList"  resultType="com.example.entity.User">

            select * from  user

        </select>
</mapper>

7.编写测试类

package com.example.dao;

import com.example.dao.UserDao;
import com.example.entity.User;
import com.example.utils.MybatisUtils;
import org.apache.ibatis.session.SqlSession;
import org.junit.Test;

import javax.annotation.Resource;
import java.util.List;

public class UserDaoTest {
    @Test
    public void test() {
        //第一步获取Sqlsession  对象
        SqlSession sqlSession = MybatisUtils.getSqlSession();
        try {
            //        sqlSession.close();
            //执行sql
            UserDao userDao = sqlSession.getMapper(UserDao.class);
            List<User> userlist = userDao.getUserList();
            for (User user : userlist) {
                System.out.println(user);
            }
        }
        catch(Exception e){
            System.out.println(e);

            }
        finally{
                //关闭sqlsession
                sqlSession.close();
            }

    }
}

注:需放在pom <build></build>

···
可能出现问题说明：Maven静态资源过滤问题

<resources>
<resource>
<directory>src/main/java</directory>
<includes>
<include>/.properties</include>
<include>/.xml</include>
</includes>
<filtering>false</filtering>
</resource>
<resource>
<directory>src/main/resources</directory>
<includes>
<include>/.properties</include>
<include>/.xml</include>
</includes>
<filtering>false</filtering>
</resource>
</resources>
···