Mybatis3.0-[tp_28-29]-映射文件-resultMap_自定义结果集映射规则_及关联环境的搭建

笔记要点
出错分析与总结
工程组织

1.定义接口  EmployeeMapperPlus.java

package com.dao;
import com.bean.*;
public interface EmployeeMapperPlus {
    public Employee getEmpById(Integer id);
}

2.定义映射文件    EmployeeMapperPlus.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.dao.EmployeeMapperPlus">

   <!--ResultMap ;自定义结果集映射规则;
        type: 自定义规则的Java类型;id: 唯一的标识,方便引用-->
    <resultMap id="MyEmp" type="com.bean.Employee">
        <!--指定主键列的封装规则,id定义主键,底层会有优化规则;
        column : 指定具体的那一列; property:指定的JavaBean对应的属性-->
        <id column="id" property="id"/>
        <!--定义普通列的封装规则-->
        <result column="last_name" property="lastName"/>
        <!--,其他不指定的列会自动封装;我们只要写ResultMap,就把剩下的映射全部都写上-->
        <result column="email" property="email"/>
        <result column="gender" property="gender"/>
    </resultMap>

    <!--public Employee getEmpById(Integer id);   注意进行更改为resultMap-->
    <select id="getEmpById" resultMap="MyEmp">
        select * from tbl_employee where id=#{id}
    </select>
    <!--场景1

    -->

</mapper>

(关闭了驼峰规则,验证自定义配置)

3.编写测试代码  test_tp28

public class test_tp28 {
    public SqlSessionFactory getSqlSessionFactory() throws IOException {
        String resource = "mybatis-config.xml";
        InputStream inputStream=Resources.getResourceAsStream(resource);
        return new SqlSessionFactoryBuilder().build(inputStream);
    }
    @Test
    public void test06() throws Exception{
        //默认是不自动提交数据的,需要我们自己手动提交
        SqlSession openSession = getSqlSessionFactory().openSession();
        try {
            EmployeeMapperPlus mapper = openSession.getMapper(EmployeeMapperPlus.class);
            Employee empById = mapper.getEmpById(1);
            System.out.println(empById);

            //最后手动提交
            openSession.commit();
        }finally {
            openSession.close();
        }
    }

}

测试结果

DEBUG 11-29 17:32:44,565 ==>  Preparing: select * from tbl_employee where id=?   (BaseJdbcLogger.java:145) 
DEBUG 11-29 17:32:44,584 ==> Parameters: 1(Integer)  (BaseJdbcLogger.java:145) 
DEBUG 11-29 17:32:44,597 <==      Total: 1  (BaseJdbcLogger.java:145) 
Employee{id=1, lastName='jerry', email='jerry@163.com', gender='1'}