mybatis延迟加载

博客：https://blog.csdn.net/PostersXu/article/details/79053916

<select id="queryByID" resultMap="pojoResultMap">
        SELECT
            *
        FROM
            <include refid="tableName"/>
        WHERE order_id = #{id};
    </select>
<sql id="tableName">tb_order</sql>

<resultMap type="Order" id="pojoResultMap" autoMapping="true">
        <id column="order_id" property="orderId"/>
        <association property="orderShipping" javaType="OrderShipping" column="order_id" select="queryOrderShippingByOrderId" autoMapping="true"></association>
        <collection property="orderItems" javaType="Arraylist" ofType="OrderItem" autoMapping="true" select="queryOrderItemByOrderId" column="order_id">
        </collection>
    </resultMap>
    
    <select id="queryOrderItemByOrderId" resultType="OrderItem" parameterType="String">
        SELECT * FROM tb_order_item WHERE order_id = #{orderId};
    </select>
    
    <select id="queryOrderShippingByOrderId" resultType="OrderShipping" parameterType="String">
        SELECT * FROM tb_order_shipping WHERE order_id = #{orderId};
    </select>

<!-- 延迟加载配置 -->

<settings>
<!-- 开启字段名和属性名驼峰似的匹配 -->
<setting name="mapUnderscoreToCamelCase" value="true" />
<!-- 开启延迟加载 -->
<setting name="lazyLoadingEnabled" value="true" />
<!-- 按需延迟加载 -->
<setting name="aggressiveLazyLoading" value="false" />
</settings>