十一、resultMap 的关联方式实现多表查询(一对 多)

 1 <?xml version="1.0" encoding="UTF-8" ?>
 2 <!DOCTYPE mapper
 3         PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
 4         "http://mybatis.org/dtd/mybatis-3-mapper.dtd">
 5 <mapper namespace="com.mapper.ClazzMapper">
 6     <!--开启二级缓存-->
 7     <cache/>
 8     <resultMap id="classMap" type="Clazz">
 9         <id property="id" column="cid"/>
10         <result property="name" column="cname"/>
11         <result property="room" column="room"/>
12         <collection property="stu" javaType="list" ofType="Student">
13             <id property="id" column="sid"/>
14             <result property="name" column="sname"/>
15             <result property="age" column="age"/>
16             <result property="gender" column="gender"/>
17             <result property="cid" column="cid"/>
18         </collection>
19     </resultMap>
20     <select id="selAll" resultMap="classMap">
21         select c.id cid, c.name cname, c.room, s.id sid, s.name sname, s.age, s.gender
22         from t_student s
23         right join t_class c
24         on s.cid=c.id
25     </select>
26 
27 </mapper>