Mybatis学习第17节 -- 嵌套查询(多对一和一对一)

package io.github.coinsjack.pojo;

import java.io.Serializable;
import java.sql.Date;

public class Shop implements Serializable{

    Area area;

public class Area implements Serializable{

    Integer id;
    String name;
    Integer priority;

    Date createTime;
    Date lastEditTime;

<resultMap id="simpleResultMap" type="Shop">
    <id column="shop_id" property="id" ></id>
    <result column="owner_id" property="ownerId" ></result>
    <result column="shop_category_id" property="categoryId" ></result>
    <result column="shop_name" property="name"></result>
    <result column="shop_desc" property="desc"></result>
    <result column="shop_addr" property="addr"></result>
    <result column="phone" property="phone"></result>
    <result column="shop_img" property="image"></result>
    <result column="priority" property="priority"></result>
    <result column="create_time" property="createTime"></result>
    <result column="last_edit_time" property="lastEditTime"></result>
    <result column="enable_status" property="enableStatus"></result>
    <association property="area" column="area_id" javaType="Area"
                 select="io.github.coinsjack.dao.AreaMapper.getAreaById"/>
</resultMap>

<select id="getShopById" parameterType="int" resultMap="simpleResultMap" >
    select * from tb_shop where `shop_id` = #{id}
</select>

<?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="io.github.coinsjack.dao.AreaMapper">

    <cache/>

    <resultMap id="areaResultMap" type="Area">
        <result column="area_id" property="id"/>
        <result column="area_name" property="name"/>
        <result column="create_time" property="createTime"/>
        <result column="last_edit_time" property="lastEditTime"/>
    </resultMap>

    <select id="getAreaById" resultMap="areaResultMap">
        select * from tb_area
        WHERE `area_id` = #{id};
    </select>
</mapper>

public interface AreaMapper {

    Area getAreaById(Integer id);
}

@Test
public void testGetShopById() {
    SqlSession session = MyBatisUtil.getSqlSession();
    ShopMapper mapper = session.getMapper(ShopMapper.class);
    System.out.println(mapper.getShopById(1));
    session.close();
}