mybatis 使用（3）一对多关联映射

TypeMapper.xml

<?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="com.mybatis.mapper.TypeMapper">
	<!-- 根据商品类型编号查询商品类型信息 -->
	<select id="findTypeById" parameterType="int" resultMap="typeMap">
		select *
		from type where id = #{id}
	</select>
	<resultMap type="Type" id="typeMap">
		<id property="id" column="id" />
		<result property="name" column="name" />
		<!-- 一对多关联映射 -->
		<collection property="pis" column="id"
			select="com.mybatis.mapper.ProductInfoMapper.findProductInfoById">
		</collection>
	</resultMap>

	<!-- 使用嵌套结果查询方式实现一对多关联查询 -->
	<select id="findTypeById2" parameterType="int" resultMap="typeMap2">
		select
		t.id tid, t.name tname, pi.* from type t,product_info pi where
		pi.tid=t.id and t.id=#{id}
	</select>
	<resultMap type="Type" id="typeMap2">
		<id property="id" column="tid" />
		<result property="name" column="tname" />
		<!-- 一对多关联映射 -->
		<collection property="pis" ofType="ProductInfo">
			<id property="id" column="id" />
			<result property="code" column="code" />
			<result property="name" column="name" />
		</collection>
	</resultMap>

	<!-- 向type表插入数据 -->
	<insert id="addType" parameterType="Type">
		<!-- 插入数据,并获得刚插入数据表type的记录id -->
		<selectKey keyProperty="id" resultType="int" order="AFTER">
			SELECT
			LAST_INSERT_ID() AS ID
		</selectKey>
		insert into type(name) values(#{name})
	</insert>

	<!-- 删除数据 -->
	<delete id="deleteTypeById" parameterType="int">
		delete from
		product_info where tid = #{id};
		delete from type where id = #{id};
	</delete>

</mapper>

ProductInfoMapper.xml

<?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="com.mybatis.mapper.ProductInfoMapper">
	<!-- 根据类型编号查询商品信息 -->
	<select id="findProductInfoById" parameterType="int" resultType="ProductInfo">
		select * from product_info where tid = #{id}
	</select>
	
	<!-- 向 product_info表插入数据 -->
	<insert id="addProductInfo" parameterMap="addProductInfoPMap">
		insert into
		product_info(code,name,tid) values(#{code},
		#{name},#{type.id})
	</insert>
	<parameterMap type="ProductInfo" id="addProductInfoPMap">
		<parameter property="code" />
		<parameter property="name" />
		<parameter property="type.id" />
	</parameterMap>

</mapper>