java - 如何使用 typedQuery 在 Criteria api 上添加分页？

Question

我正在使用具有可分页功能的 Criteria API 来返回 Page<MyClass>可分页，但是当我插入 setFirstResult 时和setMaxResults查询始终返回 10 个元素。

如果我删除 setFirstResult和setMaxResults来自 TypedQuery，我的 typedQuery.getResultList()返回所有元素，但显然没有分页。

我有一项服务调用我的标准，发送主函数的可分页 peopleRepository.filter

public Page<People> filtrarParcial(String name, String rg, String mom, String cpf, String nickname, Integer pageNumber, Integer pageSize, List<String> sort) {
    List<Sort.Order> orders = new ArrayList<>();

    PageRequest pageRequest = PageRequest.of(pageNumber, pageSize, Sort.by(orders));

    Page<People> listPeople = peopleRepository.filter(name, rg, mom, cpf, nickname, pageRequest);

    return listPeople;
}

我的存储库实现了

@Service
public class PeopleRepositoryImpl implements PeopleRepositoryQueries {
    @PersistenceContext
    private EntityManager manager;

    @Transactional(readOnly = true)
    public Page<People> filter(String name, String rg, String mom, String cpf, String nickname, Pageable pageable) {

        CriteriaBuilder criteriaBuilder = manager.getCriteriaBuilder();
        CriteriaQuery<People> query = criteriaBuilder.createQuery(People.class);

        Root<People> root = query.from(People.class);

        Path<String> nomePath = root.<String>get("name");

        List<Predicate> predicates = new ArrayList<Predicate>();

        if(!nome.equals("")) {
            Predicate nomeIgual = criteriaBuilder.like(nomePath, "%" +name.toUpperCase() + "%");
            predicates.add(nomeIgual);
        }

        query.where((Predicate[]) predicates.toArray(new Predicate[0]));

        int paginaAtual = pageable.getPageNumber();
        int totalRegistrosPorPagina = pageable.getPageSize();
        int primeiroRegistro = paginaAtual * totalRegistrosPorPagina;

        TypedQuery<People> typedQuery = manager.createQuery(query);

//      typedQuery.setFirstResult(primeiroRegistro);
//      typedQuery.setMaxResults(totalRegistrosPorPagina);

        Integer totalRows = typedQuery.getResultList().size();

        Long total = totalRows.longValue();
        return new PageImpl<>(typedQuery.getResultList(), pageable, total);
    }

如果我搜索名为 ma​​rcos 的人，typedQuery.getResultList()按页仅返回 10 个与相同数量元素同时出现的元素(在我的数据库中有 180 个)。如果我删除这个

typedQuery.setFirstResult(primeiroRegistro);
typedQuery.setMaxResults(totalRegistrosPorPagina);

然后typedQuery.getResultList()返回 180 个元素，但带分页，所有 180 个元素都在单页内，不带分页

Answer 1

尝试使用以下配置。

CriteriaQuery<Long> countQuery = criteriaBuilder.createQuery(Long.class);
Root<People> entity_ = countQuery.from(query.getResultType());
entity_.alias("entitySub"); //use the same alias in order to match the restrictions part and the selection part
countQuery.select(criteriaBuilder.count(entity_));
Predicate restriction = query.getRestriction();
if (restriction != null) {
    countQuery.where(restriction); // Copy restrictions
}
Long totalCount=entityManager.createQuery(countQuery).getSingleResult();


query.setFirstResult(pageable.getOffset());
query.setMaxResults(pageable.getPageSize());
List<People> result = query.getResultList();
return PageableExecutionUtils.getPage(result,pageable, () -> totalCount);