1、编写Dao接口
2、编写Dao的实现
做查询
首先要编写resultMap(输出结果),<id>是主键,<result>是数据库字段和属性的对应,<association>是外键里的属性
在<select>标签中resultMap 引用的就是上面的id
<mapper namespace="com.imooc.o2o.dao.ShopDao">
<resultMap type="com.imooc.o2o.entity.Shop" id="shopMap">
<id column="shop_id" property="shopId"/>
<result column="shop_name" property="shopName"/>
<result column="shop_desc" property="shopDesc"/>
<result column="shop_addr" property="shopAddr"/>
<result column="phone" property="phone"/>
<result column="priority" property="priority"/>
<result column="create_time" property="createTime"/>
<result column="last_edit_time" property="lastEditTime"/>
<result column="enable_status" property="enableStatus"/>
<result column="advice" property="advice"/>
<association property="area" column="area_id" javaType="com.imooc.o2o.entity.Area">
<id column="area_id" property="areaId"/>
<result column="area_name" property="areaName"/>
</association>
<association property="shopCategory" column="shop_category_id" javaType="com.imooc.o2o.entity.ShopCategory">
<id column="shop_category_id" property="shopCategoryId"/>
<result column="shop_category_name" property="shopCategoryName"/>
</association>
<association property="owner" column="user_id" javaType="com.imooc.o2o.entity.PersonInfo">
<id column="user_id" property="userId"/>
<result column="name" property="name"/>
</association>
</resultMap>
<select id="queryByShopId" resultMap="shopMap" parameterType="Long">
SELECT
s.shop_id,
s.shop_name,
s.shop_desc,
s.shop_addr,
s.phone,
s.shop_img,
s.priority,
s.create_time,
s.last_edit_time,
s.enable_status,
s.advice,
a.area_id,
a.area_name,
sc.shop_category_id,
sc.shop_category_name
FROM
tb_shop s,
tb_area a,
tb_shop_category sc
WHERE
s.area_id=a.area_id
AND
s.shop_category_id=sc.shop_category_id
AND
s.shop_id=#{shopId}
</select>
3、测试