1、SqlMapConfig.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">
<!--mybatis的主配置文件-->
<configuration>
<!--    配置环境-->
    <environments default="mysql"><!-- 默认值，可以随便起，但是下面id值要和这个一样 -->
<!--        配置mysql的环境-->
        <environment id="mysql">
<!--            配置事务的类型-->
            <transactionManager type="JDBC"></transactionManager>
<!--            配置数据源（连接池）-->
            <dataSource type="POOLED">
<!--                配置连接数据库的4个基本信息-->
                <property name="driver" value="com.mysql.jdbc.Driver"></property>
                <property name="url" value="jdbc:mysql://localhost:3306/eesy_mybatis"></property>
                <property name="username" value="root"></property>
                <property name="password" value="123456"></property>
            </dataSource>
        </environment>
    </environments>
<!--    指定映射配置文件的位置，映射配置文件是指每个dao独立的配置文件-->
    <mappers>
        <mapper resource="com/itheima/dao/IUserDao.xml"/>
    </mappers>
</configuration>

2、IUserDao.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.itheima.dao.IUserDao"><!-- dao的权限定类名 -->
<!--    配置查询所有-->
    <select id="findAll" resultType="com.itheima.domain.User">
        select * from user
    </select>
</mapper>

3、mybatisTest.java 测试类：

package com.itheima.test;
import com.itheima.dao.IUserDao;
import com.itheima.domain.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 java.io.InputStream;
import java.util.List;

public class MybatisTest {
    public static void main(String[] args) throws Exception {
        //读取配置文件
        InputStream in = Resources.getResourceAsStream("SqlMapConfig.xml");
        //创建SqlSessionFactory工厂
        SqlSessionFactoryBuilder builder = new SqlSessionFactoryBuilder();
        SqlSessionFactory factory = builder.build(in);
        //使用工厂创建SqlSession对象
        SqlSession session = factory.openSession();
        //使用SqlSession创建Dao接口的代理对象
        IUserDao userDao = session.getMapper(IUserDao.class);
        //使用代理对象执行方法
        List<User> users = userDao.findAll();
        for(User user:users){
            System.out.println(user);
        }
        //释放资源
        session.close();
        in.close();

    }
}

4、IUserDao.java :

package com.itheima.dao;

import com.itheima.domain.User;

import java.util.List;

//用户的持久层接口
public interface IUserDao {
    List<User> findAll();
}

5、user.java :

package com.itheima.domain;

import java.io.Serializable;

public class User implements Serializable {//实现Serializable的目的可能是字符串序列
    private Integer 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 Integer getId() {
        return id;
    }

    public void setId(Integer 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;
    }
}