java - QueryDsl boolean 生成器 : How to create a predicate that compares another field?

Question

我有一个简单的例子:查找所有已售完的商品。

项目具有initialQuantity 和soldQuantity 整数字段。(由于某种原因，我需要存储初始数量)

我正在尝试做类似的事情:

builder = new BooleanBuilder();
Predicate predicate = builder.and(item.initialQuantity.eq(item.soldQuantity)).getValue();
Iterable<Item> iterable = itemRepository.findAll(predicate);

但它没有按预期返回。 “.eq()”看起来需要一个整数而不是 Path<>

Answer 1

首先声明它:

JPAQueryFactory query = new JPAQueryFactory(em);
BooleanBuilder booleanBuilder = new BooleanBuilder();
QCreditRequest creditRequest = QCreditRequest.creditRequest;

然后，您可以包含您的业务逻辑，例如:

booleanBuilder.and(creditRequest.creditRequestId.eq(dataRequest.getCreditRequestId()));

if (StringUtils.isNotBlank(dataRequest.getProductId())){
                 booleanBuilder.and(creditRequest.product.productId.eq(dataRequest.getProductId()));}

最终返回结果，映射到您的 DTO:

return new HashSet<>(
            query
                .select(
                    Projections.constructor(
                        APResponse.class,
                        creditRequest.creditRequestId,
                        creditRequest.creditRequestDate,
                        creditRequest.product.productId,
                        creditRequest.creditRequestComment))
                .from(creditRequest)
                .innerJoin(creditRequest.product, product)
                .innerJoin(creditRequest.status, creditRequestStatus)
                .where(booleanBuilder)
                .fetch());