Shop实体类
package io.github.coinsjack.pojo;
import java.io.Serializable;
import java.sql.Date;
public class Shop implements Serializable{
Area area;
} |
Area实体类
public class Area implements Serializable{
Integer id;
String name;
Integer priority;
Date createTime;
Date lastEditTime;
|
ShopMapper映射文件
<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>
|
这里需要注意, association必须放置在result后面
AreaMapper映射文件
<?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>
|
AreaMapper接口
public interface AreaMapper {
Area getAreaById(Integer id);
}
|
测试用例
@Test
public void testGetShopById() {
SqlSession session = MyBatisUtil.getSqlSession();
ShopMapper mapper = session.getMapper(ShopMapper.class);
System.out.println(mapper.getShopById(1));
session.close();
}
|
运行结果
2018-12-28 20:33:07,171 [main] DEBUG [io.github.coinsjack.dao.ShopMapper] - Cache Hit Ratio [io.github.coinsjack.dao.ShopMapper]: 0.0
2018-12-28 20:33:07,565 [main] DEBUG [io.github.coinsjack.dao.ShopMapper.getShopById] - ==> Preparing: select * from tb_shop where `shop_id` = ?
2018-12-28 20:33:07,655 [main] DEBUG [io.github.coinsjack.dao.ShopMapper.getShopById] - ==> Parameters: 1(Integer)
2018-12-28 20:33:07,728 [main] DEBUG [io.github.coinsjack.dao.AreaMapper.getAreaById] - ====> Preparing: select * from tb_area WHERE `area_id` = ?;
2018-12-28 20:33:07,729 [main] DEBUG [io.github.coinsjack.dao.AreaMapper.getAreaById] - ====> Parameters: 3(Integer)
2018-12-28 20:33:07,736 [main] DEBUG [io.github.coinsjack.dao.AreaMapper.getAreaById] - <==== Total: 1
2018-12-28 20:33:07,737 [main] DEBUG [io.github.coinsjack.dao.ShopMapper.getShopById] - <== Total: 1
Shop{id=1, ownerId=1, area=Area{id=3, name='长治学院', priority=2, createTime=null, lastEditTime=null}, categoryId=14, name='new 正式店铺名称', desc='测试描述', addr='正式地址', phone='13810524086', image='/upload/item/shop/1/2017091621545314507.jpg', priority=10, createTime=2017-08-03, lastEditTime=2017-09-16, enableStatus=0, advice='审核中'} |
总结
观察Preparing可以明显从结果中看出,进行了嵌套查询.
