<select id="querytcclass" parameterType="Cclass" resultMap="getClassesMap">        select c.cid,c.cname,s.sname,s.age from test.cclass c ,test.student s where s.cid=c.cid    </select>
    
    <resultMap type="com.ordermeal.PO.Cclass" id="getClassesMap">
        <id column="cid" property="cid"></id>
        <result column="cname" property="cname"/>
        
        <collection property="Student" ofType="com.ordermeal.PO.Student">
            <id column="sid" property="sid"/>
            <result column="sname" property="sname"/>
            <result column="cid" property="cid"/>
            <result column="age" property="age"/>
        </collection>
    </resultMap>