3.1 源码环境搭建

• mybatis源码地址：https://github.com/mybatis/mybatis-3

3.2 源码导入&编译

3.3 编写测试代码

3.3.1 配置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">


<configuration>
    
    <!--第一部分：数据源配置-->
    <environments default="development">
        <environment id="development">
            <!-- 使用jdbc事务管理 -->
            <transactionManager type="JDBC" />
            <!-- 数据库连接池 -->
            <dataSource type="POOLED">
                <property name="driver" value="com.mysql.cj.jdbc.Driver" />
                <property name="url"
                          value="jdbc:mysql:///zdy_mybatis?useSSL=false&amp;characterEncoding=UTF-8&amp;serverTimezone=UTC" />
                <property name="username" value="root" />
                <property name="password" value="root" />
            </dataSource>
        </environment>
    </environments>


   <!--第二部分：引入映射配置文件-->
    <mappers>
      <mapper resource="mapper/UserMapper.xml"></mapper>
    </mappers>
    
</configuration>

3.3.2 配置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">


<mapper namespace="user">
 
  <select id="findUserById" parameterType="int" resultType="com.itheima.pojo.User">
        SELECT id,username FROM  user WHERE id = #{id}
    </select>
  
</mapper>

3.3.3 编写User类

package com.itheima.pojo;


import lombok.Data;


@Data
public class User {


    // ID标识
    private Integer id;
    // 用户名
    private String username;


}

3.3.5 编写测试类

public class MybatisTest {


      @Test
      public void test1() throws IOException {


        InputStream resourceAsStream = Resources.getResourceAsStream("SqlMapConfig.xml");
        SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(resourceAsStream);
        SqlSession sqlSession = sqlSessionFactory.openSession();


        User user = sqlSession.selectOne("user.findUserById", user1);
        System.out.println(user);
        System.out.println("MyBatis源码环境搭建成功...");
        sqlSession.close();
      }


}

输出：