MySql批量插入数据，已经存在的更新，不存在新增

<insert id="batchDeviceUser">
    insert into iot_device_user(device_id, user_id) values
    <foreach item="item" index="index" collection="list" separator=",">
        (#{item.deviceId},#{item.userId})
    </foreach>
    ON DUPLICATE KEY UPDATE
    user_id = VALUES(user_id)
</insert>