Mybatis 批量更新實體對象方式

Mybatis 批量更新實體對象

(1)Dao層接口

    /**
     * 根據更新采購計劃(批量)
     * @param plans
     */
    void batchUpdatePlan(List<PubPurchasePlan> plans);

(2)Mapper.xml 文件

<sql id="batchUpdatePlanCondition">
    <where>
        <foreach collection="list" item="item" open="( " separator=") or (" close=" )">
            comId = #{item.comId} AND id = #{item.id}
        </foreach>
    </where>
</sql>
<update id="batchUpdatePlan" parameterType="list">
        UPDATE pub_purchase_plan
        <trim prefix="set" suffixOverrides=",">
            <trim prefix="warehouseId=case" suffix="end,">
                 <foreach collection="list" item="item" index="index">
                    WHEN comId = #{item.comId} AND id = #{item.id} THEN #{item.warehouseId}
                 </foreach>
            </trim>
            <trim prefix="productId=case" suffix="end,">
                 <foreach collection="list" item="item" index="index">
                   WHEN comId = #{item.comId} AND id = #{item.id} THEN #{item.productId}
                 </foreach>
            </trim>
            <trim prefix="amount=case" suffix="end,">
                 <foreach collection="list" item="item" index="index">
                   WHEN comId = #{item.comId} AND id = #{item.id} THEN #{item.amount}
                 </foreach>
            </trim>
            <trim prefix="deleted=case" suffix="end,">
                 <foreach collection="list" item="item" index="index">
                   WHEN comId = #{item.comId} AND id = #{item.id} THEN #{item.deleted}
                 </foreach>
            </trim>
            <trim prefix="price=case" suffix="end,">
                 <foreach collection="list" item="item" index="index">
                   WHEN comId = #{item.comId} AND id = #{item.id} THEN #{item.price}
                 </foreach>
            </trim>
            <trim prefix="type=case" suffix="end,">
                 <foreach collection="list" item="item" index="index">
                   WHEN comId = #{item.comId} AND id = #{item.id} THEN #{item.type}
                 </foreach>
            </trim>
        </trim>
        <include refid="batchUpdatePlanCondition"/>
</update>
 

Mybatis批量更新數據三種方法效率對比

探討批量更新數據三種寫法的效率問題

實現方式有三種

  • 1、用for循環通過循環傳過來的參數集合,循環出N條sql
  • 2、用mysql的case when 條件判斷變相的進行批量更新
  • 3、用ON DUPLICATE KEY UPDATE進行批量更新

下面進行實現。

註意第一種方法要想成功,需要在db鏈接url後面帶一個參數 &allowMultiQueries=true

即: jdbc:mysql://localhost:3306/mysqlTest?characterEncoding=utf-8&allowMultiQueries=true

其實這種東西寫過來寫過去就是差不多一樣的代碼,不做重復的贅述,直接上代碼。

 
    <!-- 批量更新第一種方法,通過接收傳進來的參數list進行循環著組裝sql -->
     <update id="updateBatch" parameterType="java.util.List" >
        <foreach collection="list" item="item" index="index" open="" close="" separator=";">
            update standard_relation
            <set >
                <if test="item.standardFromUuid != null" >
                    standard_from_uuid = #{item.standardFromUuid,jdbcType=VARCHAR},
                </if>
                <if test="item.standardToUuid != null" >
                    standard_to_uuid = #{item.standardToUuid,jdbcType=VARCHAR},
                </if>
                <if test="item.gmtModified != null" >
                    gmt_modified = #{item.gmtModified,jdbcType=TIMESTAMP},
                </if>
            </set>
            where id = #{item.id,jdbcType=BIGINT}
        </foreach>
    </update>
 
    <!-- 批量更新第二種方法,通過 case when語句變相的進行批量更新 -->
    <update id="updateBatch" parameterType="java.util.List" >
        update standard_relation
        <trim prefix="set" suffixOverrides=",">
            <trim prefix="standard_from_uuid =case" suffix="end,">
                <foreach collection="list" item="i" index="index">
                    <if test="i.standardFromUuid!=null">
                        when id=#{i.id} then #{i.standardFromUuid}
                    </if>
                </foreach>
            </trim>
            <trim prefix="standard_to_uuid =case" suffix="end,">
                <foreach collection="list" item="i" index="index">
                    <if test="i.standardToUuid!=null">
                        when id=#{i.id} then #{i.standardToUuid}
                    </if>
                </foreach>
            </trim>
            <trim prefix="gmt_modified =case" suffix="end,">
                <foreach collection="list" item="i" index="index">
                    <if test="i.gmtModified!=null">
                        when id=#{i.id} then #{i.gmtModified}
                    </if>
                </foreach>
            </trim>
        </trim>
        where
        <foreach collection="list" separator="or" item="i" index="index" >
            id=#{i.id}
        </foreach>
    </update>
批量更新第三種方法,用ON DUPLICATE KEY UPDATE
 <insert id="updateBatch" parameterType="java.util.List">
        insert into standard_relation(id,relation_type, standard_from_uuid,
        standard_to_uuid, relation_score, stat,
        last_process_id, is_deleted, gmt_created,
        gmt_modified,relation_desc)VALUES
        <foreach collection="list" item="item" index="index" separator=",">
            (#{item.id,jdbcType=BIGINT},#{item.relationType,jdbcType=VARCHAR}, #{item.standardFromUuid,jdbcType=VARCHAR},
            #{item.standardToUuid,jdbcType=VARCHAR}, #{item.relationScore,jdbcType=DECIMAL}, #{item.stat,jdbcType=TINYINT},
            #{item.lastProcessId,jdbcType=BIGINT}, #{item.isDeleted,jdbcType=TINYINT}, #{item.gmtCreated,jdbcType=TIMESTAMP},
            #{item.gmtModified,jdbcType=TIMESTAMP},#{item.relationDesc,jdbcType=VARCHAR})
        </foreach>
        ON DUPLICATE KEY UPDATE
        id=VALUES(id),relation_type = VALUES(relation_type),standard_from_uuid = VALUES(standard_from_uuid),standard_to_uuid = VALUES(standard_to_uuid),
        relation_score = VALUES(relation_score),stat = VALUES(stat),last_process_id = VALUES(last_process_id),
        is_deleted = VALUES(is_deleted),gmt_created = VALUES(gmt_created),
        gmt_modified = VALUES(gmt_modified),relation_desc = VALUES(relation_desc)
    </insert>
 @Override
    public void updateStandardRelations() {
        List<StandardRelation> list=standardRelationMapper.selectByStandardUuid("xiemingjieupdate");
        for(StandardRelation tmp:list){
            tmp.setStandardFromUuid(tmp.getStandardFromUuid()+"update");
            tmp.setStandardToUuid(tmp.getStandardToUuid()+"update");
        }
        long begin=System.currentTimeMillis();
        standardRelationManager.updateBatch(list);
        long end=System.currentTimeMillis();
        System.out.print("當前的批量更新的方法用時"+(end-begin)+"ms");
    }

sql語句for循環效率其實相當高的,因為它僅僅有一個循環體,隻不過最後update語句比較多,量大瞭就有可能造成sql阻塞。

case when雖然最後隻會有一條更新語句,但是xml中的循環體有點多,每一個case when 都要循環一遍list集合,所以大批量拼sql的時候會比較慢,所以效率問題嚴重。使用的時候建議分批插入。

duplicate key update可以看出來是最快的,但是一般大公司都禁用,公司一般都禁止使用replace into和INSERT INTO … ON DUPLICATE KEY UPDATE,這種sql有可能會造成數據丟失和主從上表的自增id值不一致。而且用這個更新時,記得一定要加上id,而且values()括號裡面放的是數據庫字段,不是java對象的屬性字段。

根據效率,安全方面綜合考慮,選擇適合的很重要。

以上為個人經驗,希望能給大傢一個參考,也希望大傢多多支持WalkonNet。

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