1.Question Description: sometimes, POJO bean contains another bean or collection as property, it's suitable for select data from more than one table. ...
1.Question Description:
sometimes, POJO bean contains another bean or collection as property,
it's suitable for select data from more than one table.
2. Solution:
2.1 mybatis mapper file , for example:
<mapper namespace="cn.net.syl.dao.ProductsMapper" >
<resultMap id="BaseResultMap" type="cn.net.syl.model.Products" >
<id column="product_id" property="productId" jdbcType="BIGINT" />
<result column="product_name" property="productName" jdbcType="VARCHAR" />
<result column="title" property="title" jdbcType="VARCHAR" />
<result column="descript" property="descript" jdbcType="VARCHAR" />
<result column="price" property="price" jdbcType="DOUBLE" />
......
</resultMap>
.....
<resultMap type="cn.net.syl.model.Products" id="BigResultMap" extends="BaseResultMap">
<association property="prodExt" javaType="cn.net.syl.model.ProductsExt">
<id column="product_ext_id" property="productExtId" jdbcType="BIGINT" />
<result column="product_id" property="productId" jdbcType="BIGINT" />
....
</association>
<collection property="prodPropImgList" ofType="cn.net.syl.model.ProductsPreviewImages">
<id column="prev_id" property="prevId" jdbcType="BIGINT" />
<result column="product_id" property="productId" jdbcType="BIGINT" />
..........
</collection>
</resultMap>
<select id="getProductInfo" resultMap="BigResultMap" parameterType="java.lang.Long">
select
a.*, b.detail_descript,
c.image_url,
c.product_id,
c.property_id,
c.value_id,
d.value_name
FROM
syl_products a,
syl_products_ext b,
syl_products_preview_images c,
syl_property_values d
where a.product_id = b.product_id
and a.product_id = c.product_id
and c.value_id = d.value_id
and a.product_id = #{productId}
</select>
</mapper>
2.2 POJO bean , for example:
public class Products {
private String idStr;
private Long productId;
private String productName;
............
//add field for sql
private ProductsExt prodExt;
//add field for sql
List<ProductsPreviewImages> prodPropImgList;
//add field for sql
private List<ProductPropertyEntity> baseProdPropList;
//getter and setter method
....
}