association 的使用

	<resultMap id="wmsTaskMap" type="WmsTask">

		<id column="ID" jdbcType="DECIMAL" property="id" />
		<result column="TYPE" jdbcType="VARCHAR" property="type" />
		<result column="INVENTORY_STATUS" jdbcType="VARCHAR" property="inventoryStatus" />
		<result column="SRC_INVENTORY_ID" jdbcType="DECIMAL" property="srcInventoryId" />
		<result column="SRC_LOCATION_ID" jdbcType="DECIMAL" property="srcLocationId" />
		<result column="SRC_LOCATION_CODE" jdbcType="VARCHAR" property="srcLocationCode" />
		<result column="DEST_INVENTORY_ID" jdbcType="DECIMAL" property="destInventoryId" />
		<result column="DEST_LOCATION_ID" jdbcType="DECIMAL" property="destLocationId" />
		<result column="DEST_LOCATION_CODE" jdbcType="VARCHAR" property="destLocationCode" />
		<result column="PLAN_QUANTITY_BU" jdbcType="DECIMAL" property="planQuantityBU" />
		<result column="MOVED_QUANTITY_BU" jdbcType="DECIMAL" property="movedQuantityBU" />
		<result column="STATUS" jdbcType="VARCHAR" property="status" />

		<result property="info.creatorId" column="CREATOR_ID" />
		<result property="info.creator" column="CREATOR" />
		<result property="info.createdTime" column="CREATED_TIME" />
		<result property="info.lastOperatorId" column="LAST_OPERATOR_ID" />
		<result property="info.lastOperator" column="LAST_OPERATOR" />
		<result property="info.lastOperatedTime" column="LAST_OPERATED_TIME" />

		<association property="worker" column="WORKER_ID" javaType="User">
			<id column="ID" jdbcType="DECIMAL" property="id" />
		</association>
		<association property="productKey" column="PRODUCT_KEY_ID" javaType="WmsProductKey">
			<id column="ID" jdbcType="DECIMAL" property="id" />
		</association>
		<association property="workDoc" column="WORK_DOC_ID" javaType="WmsWorkDoc">
			<id column="ID" jdbcType="DECIMAL" property="id" />
			<!-- 单据编号 -->
			<result column="CODE" jdbcType="VARCHAR" property="code" />
		</association>
		<!--  -->
		<association property="moveDocDetail" column="MOVE_DOC_DETAIL_ID" javaType="WmsMoveDocDetail">
			<id column="ID" jdbcType="DECIMAL" property="id" />
			<association property="product" column="PRODUCT_ID" javaType="BisProduct">
				<id column="ID" jdbcType="DECIMAL" property="id" />
				<result column="CODE" jdbcType="VARCHAR" property="code" />
				<result column="NAME" jdbcType="VARCHAR" property="name" />
			</association>
		</association>
		<!-- 包装级别 -->
		<association property="packageLevel" column="PACKAGE_LEVEL_ID"
			javaType="BisPackageLevel"
			select="com.jshuabo.logistics.server.dao.bis.product.IBisPackageLevelMapper.load" />

	</resultMap>

为什么 association 关联不出信息， 仅仅有Id：

<association property="moveDocDetail" column="MOVE_DOC_DETAIL_ID" javaType="WmsMoveDocDetail">
			<id column="ID" jdbcType="DECIMAL" property="id" />
			<association property="product" column="PRODUCT_ID" javaType="BisProduct">
				<id column="ID" jdbcType="DECIMAL" property="id" />
				<result column="CODE" jdbcType="VARCHAR" property="code" />
				<result column="NAME" jdbcType="VARCHAR" property="name" />
			</association>
		</association>