java - 值(value)返回方法JPQL的最佳实践是什么

Question

我需要寻求支持，在这段代码中我最初只需要两个字段， 但我不确定如果只有两个字段或整个对象，如何最好地将查询值返回到下面的方法。

提前致谢

  public LocalDE localizaPorItemstockdeposit(   final BigInteger ItemId, 
                                                  final BigInteger stockId, 
                                                  final BigInteger depositId){

        StringBuilder sql = new StringBuilder();

        sql.append(" SELECT ")
           .append("     c.bkLocationC, ")
           .append("     d.bkStockTypeC ") 
           .append("   FROM LocalDE c ") 
           .append("     JOIN a.partsXWarehouseDE b ")
           .append("     JOIN a.depositDE c  ")
           .append("     JOIN a.TypedepositDE d ")
           .append("   WHERE ")
           .append("      a.ItemId = :ItemId AND")
           .append("      a.stockId = :stockId AND") 
           .append("      a.bkdepositId  = :depositId ");         

        TypedQuery<LocalDE> query = this.entityManager().createQuery(sql.toString(), LocalDE.class);

        query.setParameter("ItemId", ItemId);
        query.setParameter("stockId", stockId);
        query.setParameter("depositId", depositId);

        @SuppressWarnings("unchecked")
        List lstitemxStockxDeposit = query.getResultList();
        java.util.Iterator it = lstitemxStockxDeposit.iterator(); 

        LocalDE itemxStockxDeposit = new LocalDE();
        depositDE deposit = new depositDE();
        TypedepositDE  typeDeposit = new TypedepositDE();

        while(it.hasNext()) {
            Object[] resultitemxStockxDeposit =(Object[]) it.next();

            deposit.setDepositDesc(String.valueOf(resultitemxStockxDeposit[0]));
            typeDeposit.setTypeDepositDEsc(String.valueOf(resultitemxStockxDeposit[1]));

            itemxStockxDeposit.setDepositDE(deposit);
            itemxStockxDeposit.setTypeDepositDE(typeDeposit);
        }

        return itemxStockxDeposit;

    }

Answer 1

我曾经创建这样的 DTO:

public class StockxDepositDTO {

        private String deposit;
        private String typeDeposit;

        //with a constructor
        public StockxDepositDTO(String deposit, String typeDeposit){
             this.deposit = deposit;
             this.typeDeposit = typeDeposit;
    }
}

因此，当您获取数据时，可以使用此 DTO 代替结果集，如下所示:

“从...中选择新的 com.stackoverflow.repository.StockxDepositDTO(c.bkLocationC, d.bkStockTypeC )”

结果，您将收到一个 StockxDepositDTO 列表，其中包含您需要的两个字段。