springbootJpa + QueryDsl查詢組件的聯合運用<記錄>

pom.xml中加入依賴:

  <!-- QueryDSL -->
        <dependency>
            <groupId>com.querydsl</groupId>
            <artifactId>querydsl-jpa</artifactId>
            <version>${querydsl.version}</version>
        </dependency>
        <dependency>
            <groupId>com.querydsl</groupId>
            <artifactId>querydsl-apt</artifactId>
            <version>${querydsl.version}</version>
            <scope>provided</scope>
        </dependency>

 業務服務層:<示例>

//引入JPA EntityManager
@PersistenceContext
private EntityManager entityManager;

　　　　// 今日累計津貼
        BigDecimal todaySubsidyTotal = new JPAQuery<>(entityManager)
                .select(QSenderRewarding.senderRewarding.amount.sum())
                .from(QSenderRewarding.senderRewarding, QAgent.agent, QSender.sender)
                .where(QAgent.agent.cityCode.eq(QSender.sender.cityId)//代理商和配送員關聯
                        .and(QSender.sender.id.eq(QSenderRewarding.senderRewarding.senderId))//配送員和配送員獎勵關聯
                        .and(QSenderRewarding.senderRewarding.createTime.between(TimeUtils.today(), Instant.now()))//配送員獎勵時間限制
                        .and(QAgent.agent.id.eq(agentId)))//根據傳入agentId找到對應代理商信息
                .fetchOne();//返回類型

 JPAQuery每次查詢都需要重新new下