Java_myBatis_消極式載入

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使用mybatis的消極式載入，需要兩個步驟：

1.在全域設定檔中添加一下語句（lazyLoadingEnabled預設為false，aggressiveLazyLoading預設為true）

<settings>    <!-- 消極式載入總開關 -->    <setting name="lazyLoadingEnabled" value="true"/>    <!-- 侵入式延遲 -->    <setting name="aggressiveLazyLoading" value="false"/></settings>

2.寫好對應檔

<resultMap type="User" id="CacheTest">    <id column="id" property="id" />    <result column="username" property="username" />    <result column="birthday" property="birthday" />    <result column="address" property="address" />    <!-- column相當於傳入parameter  ofType相當於resultType -->    <collection property="orderList" column="id" ofType="Order"        select="resultMap.resultMapMapper.CacheTestSelect">        <result column="number" property="number" />        <result column="createtime" property="createtime" />    </collection></resultMap><select id="CacheTest" resultMap="CacheTest">    select * from user</select><select id="CacheTestSelect" parameterType="int" resultType="Order">    select * from orders where user_id = #{id}</select>

這樣查詢一開始會執行select * from user

然後當讀取到orderList時才會執行select * from orders where user_id = #{id}

Java_myBatis_消極式載入