转载一篇关于mybatis中两个bean组合成的list查询对象

状况描述:当使用JOIN查询,若是SQL查询出来的记录不是按id列排序的,则生成的List结果会有问题

案例:

1) 数据库模型

简而言之一个Goods包含多个Goods_Img

2) Java Bean

Goods.java

public class Goods {

    private Integer goodsId;

    private String goodsName;

    private Integer goodsStorageNum;

    private Integer goodsScore;

    private GoodsStatus goodsStatus;

    private String goodsDescription;

    private List<GoodsImg> goodsImgList;

    ... getter and setter ...

}

GoodImg.java

public class GoodsImg {

    private Integer imgId;

    private Integer goodsId;

    private String imgDir;

    private Integer imgSize;

    private String imgName;

    ... getter and setter ...

}

 

3) Mapper

<!-- Result Map -->
    <!-- goods resultmap -->
    <resultMap id="goodsResultMap" type="com.qunar.scoresystem.bean.Goods">
        <id property="goodsId" column="goods_id" />
        <result property="goodsName" column="goods_name" />
        <result property="goodsStorageNum" column="goods_storage_num" />
        <result property="goodsScore" column="goods_score" />
        <result property="goodsDescription" column="goods_description" />
        <result property="goodsStatus" column="goods_status" />
        <collection property="goodsImgList" resultMap="goodsImgResult" />
    </resultMap>

    <!-- goodsimage resultmap -->
    <resultMap id="goodsImgResult" type="com.qunar.scoresystem.bean.GoodsImg">
        <id property="imgId" column="img_id" />
        <result property="goodsId" column="goods_id" />
        <result property="imgDir" column="img_dir" />
        <result property="imgSize" column="img_size" />
        <result property="imgName" column="img_name" />
    </resultMap>

 

4) 执行的 SQL

select 
    goods.goods_id as goods_id, 
    goods.goods_name as goods_name, 
    goods.goods_storage_num as goods_storage_num, 
    goods.goods_score as goods_score,     
    goods.goods_description as goods_description, 
    goods.goods_status as goods_status , 
    goods_img.img_name as img_name , 
    goods_img.img_dir as img_dir , 
    goods_img.img_size as img_size 
from goods 
join goods_img 
    on goods.goods_id=goods_img.goods_id

原文地址：http://www.cnblogs.com/zemliu/archive/2013/08/16/3263053.html