xml一对多映射 collection的使用

<resultMap id="UserOrderResultMap" type="User">
    <id property="id" column="user_id"/>
    <result property="name" column="name"/>
    <result property="psw" column="pwd"/>
    <result property="phone" column="phone"/>
    <result property="headImg" column="head_img"/>
    <result property="createTime" column="create_time"/>

    <!--   
         property 填写java对象中集合类属性名称
         ofType 填写集合类中的Java对象
    -->
    <collection property="videoOrderList" ofType="VideoOrder">

        <!--配置主键，管理order的唯一标识-->
        <id column="id" property="id"/>
        <result column="user_id" property="userId"/>
        <result column="out_trade_no" property="outTradeNo"/>
        <result column="state" property="state"/>
        <result column="create_time" property="createTime"/>
        <result column="total_fee" property="totalFee"/>
        <result column="video_id" property="videoId"/>
        <result column="video_title" property="videoTitle"/>
        <result column="video_img" property="videoImg"/>
    </collection>

</resultMap>
<select id="queryUserOrder" resultMap="UserOrderResultMap">
    select
    u.id,
    u.name,
    u.pwd,
    u.phone,
    u.head_img,
    u.create_time,
    o.id order_id,
    o.out_trade_no,
    o.state,
    o.create_time,
    o.total_fee,
    o.video_id,
    o.video_title,
    o.video_img

    from user u left join video_order o on u.id = o.user_id
</select>