package io.github.coinsjack.pojo;

public class ShopCustom extends Shop {

    private String shopName;
    private String shopDesc;

    public ShopCustom() {
 
    }

package io.github.coinsjack.dao;

import io.github.coinsjack.pojo.ShopCustom;

public interface ShopMapperCustom {

    ShopCustom getShopById(Integer id);

}

<?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.ShopMapperCustom">

    <cache/>
    

    <resultMap id="shopResultMap" type="ShopCustom">
        <id column="shop_id" property="id" ></id>
 
        <result column="shop_name" property="shopName"></result>
        <result column="shop_desc" property="shopDesc"/>
    </resultMap>

    <select id="getShopById" parameterType="int" resultMap="shopResultMap" >
        select `shop_id`, `shop_name`, `shop_desc`
        from tb_shop
        where `shop_id` = #{id}
    </select>
</mapper>

@Test
public void testGetShopByIdCustom() {
    SqlSession session = MyBatisUtil.getSqlSession();
    ShopMapperCustom mapper = session.getMapper(ShopMapperCustom.class);
    System.out.println(mapper.getShopById(29));
    session.close();
}