使用动态查询在 ReactiveMongoRepository 上实现分页和排序

Question

我知道分页在某种程度上违反了反应性原则，但由于要求，我必须使其以某种方式工作。我正在使用 Spring Data 2.1.6 并且无法升级，因此ReactiveQuerydslSpecification动态查询是不可能的。我想我可以使用ReactiveMongoTemplate所以我想出了这个：

public interface IPersonRepository extends ReactiveMongoRepository<Person, String>, IPersonFilterRepository {
    Flux<Person> findAllByCarId(String carId);
}

public interface IPersonFilterRepository {
    Flux<Person> findAllByCarIdAndCreatedDateBetween(String carId, PersonStatus status,
                                                             OffsetDateTime from, OffsetDateTime to,
                                                             Pageable pageable);
}

@Repository
public class PersonFilterRepository implements IPersonFilterRepository {

    @Autowired
    private ReactiveMongoTemplate reactiveMongoTemplate;

    @Override
    public Flux<Person> findAllByCarIdAndCreatedDateBetween(String carId, PersonStatus status,
                                                                   OffsetDateTime from, OffsetDateTime to,
                                                                   Pageable pageable) {
        Query query = new Query(Criteria.where("carId").is(carId));

        if (status != null) {
            query.addCriteria(Criteria.where("status").is(status));
        }

        OffsetDateTime maxLimit = OffsetDateTime.now(ZoneOffset.UTC).minusMonths(3).withDayOfMonth(1); // beginning of month
        if (from == null || from.isBefore(maxLimit)) {
            from = maxLimit;
        }

        query.addCriteria(Criteria.where("createdDateTime").gte(from));

        if (to == null) {
            to = OffsetDateTime.now(ZoneOffset.UTC);
        }

        query.addCriteria(Criteria.where("createdDateTime").lte(to));

        // problem is trying to come up with a decent page-ish behavior compatible with Flux
        /*return reactiveMongoTemplate.count(query, Person.class)
                .flatMap(count -> reactiveMongoTemplate.find(query, Person.class)
                        .flatMap(p -> new PageImpl<Person>(p, pageable, count))
                        .collectList()
                        .map());*/

        /* return reactiveMongoTemplate.find(query, Person.class)
                .buffer(pageable.getPageSize(), pageable.getPageNumber() + 1)
                //.elementAt(pageable.getPageNumber(), new ArrayList<>())
                .thenMany(Flux::from);*/
    }

我试图返回一个Page<Person>（假设这个单一方法一次可能是非反应性的），并且在运行测试时失败并出现以下错误（Spring 上下文未成功加载，因为： 。InvalidDataAccessApiUsageException: 'IDocumentFilterRepository.findAllByCustomerIdAndCreatedDateBetween' must not use sliced or paged execution. Please use Flux.buffer(size, skip)我也尝试返回Mono<Page<Person>>然后失败"Method has to use a either multi-item reactive wrapper return type or a wrapped Page/Slice type. Offending method: 'IDocumentFilterRepository.findAllByCustomerIdAndCreatedDateBetween'，所以我想我唯一的选择是返回 a Flux，根据示例 133，片段 3

Answer 1

事实证明，您只需将以下内容添加到查询对象即可：

query.with(pageable);

reactiveMongoTemplate.find(query, Person.class);

返回Flux<T>后即可开箱即用。