Mybatis 中一對多，多對一的配置

現在有很多電商平台，就拿這個來說吧。顧客跟訂單的關系，一個顧客可以有多張訂單，但是一個訂單只能對應一個顧客。

　　一對多的顧客

<?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.zdp.domain.Person">

	<resultMap type="Person" id="personBean">
		<id column="personId" property="id"/>
		<result column="personName" property="name"/>
		<result column="personAddress" property="address"/>
		<result column="personTel" property="tel"/>
		
		<!-- 一對多的關系 -->
		<!-- property: 指的是集合屬性的值, ofType：指的是集合中元素的類型 -->
		<collection property="orders" ofType="Order">
			<id column="orderId" property="id"/>
			<result column="orderNumber" property="number"/>
			<result column="orderPrice" property="price"/>
		</collection>
	</resultMap>
	
	<!-- 根據id查詢Person, 關聯將Orders查詢出來 -->
	<select id="selectPersonById" parameterType="string" resultMap="personBean">
		select p.*, o.* from person p, orders o where p.personId  = o.pid and p.personId = #{id}
	</select>
	
</mapper>


多對一的訂單

<?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.zdp.domain.Order">
	<resultMap type="Order" id="orderBean">
		<id column="orderId" property="id"/>
		<result column="orderNumber" property="number"/>
		<result column="orderPrice" property="price"/>
		
		<!-- 多對一的關系 -->
		<!-- property: 指的是屬性的值, javaType：指的是屬性的類型-->
		<association property="person" javaType="Person">
			<id column="personId" property="id"/>
			<result column="personName" property="name"/>
			<result column="personAddress" property="address"/>
			<result column="personTel" property="tel"/>
		</association>
	</resultMap>
	<!-- 根據id查詢Order, 關聯將Person查詢出來 -->
	<select id="selectOrderById" parameterType="string" resultMap="orderBean">
		select p.*, o.* from person p, orders o where p.personId  = o.pid and o.orderId = #{id}
	</select>
</mapper>

總配置: sqlMapConfig.xml

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE configuration
PUBLIC "-//mybatis.org//DTD Config 3.0//EN"
"http://mybatis.org/dtd/mybatis-3-config.dtd">
<configuration>
　　　　　／／這塊兒做了別名的配置所以上面兩個配置文件中可以使用Person和Order直接去代表類的全名
	<typeAliases>
	　　<typeAlias type="com.zdp.domain.Person" alias="Person"/>  
        　　<typeAlias type="com.zdp.domain.Order" alias="Order"/>  
	</typeAliases>
	<environments default="development">
		<environment id="development">
			<transactionManager type="JDBC" />
			<dataSource type="POOLED">
				<property name="driver" value="com.mysql.jdbc.Driver" />
				<property name="url" value="jdbc:mysql://localhost/test" />
				<property name="username" value="root" />
				<property name="password" value="root" />
			</dataSource>
		</environment>
	</environments>
	<mappers>
		<!-- 映射文件的位置 -->
		<mapper resource="com/zdp/domain/Person.xml" />
		<mapper resource="com/zdp/domain/Order.xml" />
	</mappers>
</configuration>