Mbatis高级映射

								<!-- 一对一映射 -->
<!-- 订单关联查询的resultMap 
	将整个结果映射到com.shi.POJO的Orders中
-->
<resultMap type="com.shi.POJO.Orders" id="ordersUserResultMap">
 <!-- 配置映射的订单信息 -->
	<!-- id:指定查询列中的唯一标识，订单信息中的唯一标识，如果有多个列组成唯一标识，配置多个id 
		column:指定查询列中的唯一标识，如果有多个列组成唯一标识，配置多个id
		property：订单信息的唯一标识 ，列所映射到orders中哪个属性
	-->
	<id column="id" property="id"/>
	<result column="user_id" property="user_id"/>
	<result column="number" property="number"/>
	<result column="createtime" property="createtime"/>
	<result column="note" property="note"/>
 <!-- 配置映射的关联的用户信息 -->
 	<!-- association:用于映射关联查询单个对象的信息
 	propety: 要将关联查选的用户信息映射到Orders中哪个属性 -->
 	<association property="user" javaType="com.shi.POJO.User">
 		<!-- id :关联查询用户的唯一标识
 		column：指定唯一标识用户信息的列
 		property：映射到user的哪个属性	-->
 		<id column="user_id" property="id"/>
 		<result column="username" property="username"/>
 		<result column="birthday" property="birthday"/>
 		<result column="sex" property="sex"/>
 		<result column="address" property="address"/>
 	</association>
</resultMap>

<select id="findOrderCastomResultMap" resultMap="ordersUserResultMap">
	SELECT orders.*,user.username,user.sex,user.birthday FROM orders,USER WHERE
	orders.user_id=user.id
</select>

						<!-- ================一对多映射================ -->
	
	<!-- 一对多映射查询  查询订单 ，用户信息 及订单明细表 
	 -->
	 <!-- rusultMap配置      注意：如果上面有重复的东西 可以使用  extends="" -->
	 <resultMap type="com.shi.POJO.Orders" id="OrdersAndOrderDetailResultMap" >
<!-- 订单信息 -->
	 	<id column="id" property="id"/>
	 	<result column="user_id" property="user_id"/>
	 	<result column="number" property="number"/>
	 	<result column="createtime" property="createtime"/>
	 	<result column="note" property="note"/>
<!-- 用户信息 -->
	 	<association property="user" javaType="com.shi.POJO.User">
	 		<id column="user_id" property="id"/>
	 		<result column="username" property="username"/>
	 		<result column="birthday" property="birthday"/>
	 		<result column="sex" property="sex"/>
	 		<result column="address" property="address"/>
	 	</association>
<!-- 订单明细信息 -->
	 	<!-- 
	 		一个订单关联查询出来了多条明细，所以要使用collection进行映射
	 		collection:对查询到多条记录映射到集合对象中去
	 		property：将关联查询到的多条记录映射到该orderdetailList属性中去
	 		ofType：指定映射到list集合属性中pojo的类型
	 	 -->
	 	 <collection property="orderdetailList" ofType="com.shi.POJO.Orderdetail">
	 	 	<!-- id：订单明细表的唯一标识
	 	 	property：要将订单明细的唯一标识映射到com.shi.POJO.Orderdetail 的哪个属性 -->
	 	 	<id column="orderdetail_id" property="id"/>
	 	 	<result column="items_id" property="items_id"/>
	 	 	<result column="orders_id" property="orders_id"/>
	 	 	<result column="items_num" property="items_num"/>
	 	 </collection>
	 	
	 </resultMap>	 
	 <!-- sql语句 -->
	<select id="findOrdersAndOrderDetailResultMap" resultMap="OrdersAndOrderDetailResultMap">
		SELECT
			orders.*,
			user.username,
			user.sex,
			user.address,
			orderdetail.id orderdetail_id, <!-- 注意：这里需要collection中的id  所以 不能和上面属性冲突 -->
			orderdetail.items_id,
			orderdetail.orders_id,
			orderdetail.items_num
		FROM
			orders,
			USER,
			orderdetail
		WHERE 
			orders.user_id=user.id AND orderdetail.orders_id=orders.id
	</select>

							<!-- =================多对多查询=============== -->
		<!-- 现在执行多对多查询  查询用户信息和商品信息 进行关联-->
	<!-- resultMap映射 -->
		<resultMap type="com.shi.POJO.User" id="UserAndItemsReusltMap">
			<!-- 对用户信息进行映射 -->
			<id column="user_id" property="id"/>
			<result column="username" property="username"/>
			<result column="birthday" property="birthday"/>
			<result column="sex" property="sex"/>
			<result column="address" property="address"/>
			
			<!-- 对订单进行映射   ######一对多映射######-->
			<collection property="orders" ofType="com.shi.POJO.Orders">
				<id column="id" property="id"/>
				<result column="user_id" property="user_id"/>
				<result column="number" property="number"/>
				<result column="createtime" property="createtime"/>
				<result column="note" property="note"/>
				
				<!-- 对订单细节进行映射 ######一对多映射######-->
				<collection property="orderdetailList" ofType="com.shi.POJO.Orderdetail">
					<id column="" property=""/>
					<result column="orderdetail_id" property="id"/>
					<result column="orders_id" property="orders_id"/>
					<result column="items_id" property="items_id"/>
					<result column="items_num" property="items_num"/>
					
					<!-- 对商品表进行映射  ######一对一映射###### -->
					<association property="items" javaType="com.shi.POJO.Items">
						<id column="items_id" property="id"/>
						<result column="items_name" property="name"/>
						<result column="items_price" property="price"/>
					</association>
				</collection>
			</collection>
		</resultMap>
	<!-- sql语句 -->
	<select id="findUserAndItemsReusltMap" resultMap="UserAndItemsReusltMap">
		SELECT 
			orders.*,
			user.username,
			user.sex,
			user.address,
			orderdetail.id orderdetail_id,
			orderdetail.items_id,
			orderdetail.orders_id,
			orderdetail.items_num,
			items.name items_name,
			items.price items_price
		FROM
			orders,
			USER,
			orderdetail,
			items
		WHERE 
			orders.user_id=user.id AND orderdetail.orders_id=orders.id AND orderdetail.items_id=items.id
		
	</select>