Java CriteriaQuery.multiselect方法代碼示例

import javax.persistence.criteria.CriteriaQuery; //導入方法依賴的package包/類
@Override
public Optional<SearchResponse> search(final ServiceUser user,
                                       final SearchRequest request){
    final String dataSourceUuid = request.getQuery().getDataSource().getUuid();

    try (final Session session = database.openSession()) {
        final CriteriaBuilder cb = session.getCriteriaBuilder();

        final CriteriaQuery<Tuple> cq = cb.createTupleQuery();
        final Root<T> root = cq.from(this.dtoClass);

        cq.multiselect(this.fields.stream()
                .map(f -> root.get(f.getName()))
                .collect(Collectors.toList()));

        final Predicate requestPredicate = getPredicate(cb, root, request.getQuery().getExpression());
        final Predicate dataSourcePredicate = cb.equal(root.get(QueryableEntity.DATA_SOURCE_UUID), dataSourceUuid);

        cq.where(cb.and(requestPredicate, dataSourcePredicate));
        final List<Tuple> tuples = session.createQuery(cq).getResultList();
        final SearchResponse searchResponse = projectResults(request, tuples);

        return Optional.of(searchResponse);
    }
}
 

import javax.persistence.criteria.CriteriaQuery; //導入方法依賴的package包/類
private <S> S aggregate(CriteriaBuilder builder, CriteriaQuery<S> query, Root<E> root, Specification<E> spec, List<Selection<?>> selectionList, LockModeType lockMode) {
	if (selectionList != null) {
		Predicate predicate = spec.toPredicate(root, query, builder);
		if (predicate != null) {
			query.where(predicate);
		}
		query.multiselect(selectionList);
		return (S) em.createQuery(query).setLockMode(lockMode).getSingleResult();
	}
	return null;
}
 

import javax.persistence.criteria.CriteriaQuery; //導入方法依賴的package包/類
private <R> List<R> findAllImpl2(final DatatableQuery<R, T> input, final Specifications<T> specifications,
      final Pageable pageable) {
      
      // create query
  	final EntityManager entityManager = entityManagerFactory.createEntityManager();
      final CriteriaBuilder qb = entityManager.getCriteriaBuilder();        
      final CriteriaQuery<R> cq = qb.createQuery(input.getQueryClass());

      // Etablir entité racine
      final Root<T> from = cq.from(this.entity);
      
      // select for custom class
      final List<Selection<?>> selectList = new ArrayList<Selection<?>>();
      if (input.getGroupByColumns() != null) {
          DatatableHelper.getExpressions(from, input.getGroupByColumns(), selectList);
      } else {
          DatatableHelper.getExpressions(from, input.getColumns(), selectList);
      }
      cq.multiselect(selectList);

      // where
      if (specifications != null) {
          cq.where(specifications.toPredicate(from, cq, qb));
      }

      // group by
      if (input.getGroupByColumns() != null && !input.getGroupByColumns().isEmpty()) {
          final List<Expression<?>> groupByList = new ArrayList<Expression<?>>();
          DatatableHelper.getExpressions(from, input.getGroupByColumns(), groupByList);
          cq.groupBy(groupByList);
      }

      // order by
      if (pageable != null && pageable.getSort() != null) {
          cq.orderBy(DatatableHelper.getOrderBy(from, qb, pageable));
      }

      // page limit
      final TypedQuery<R> q = entityManager.createQuery(cq);
      if (pageable != null) {
      	LOGGER.log(Level.FINE, "Pageable: offset: {0}, page size: {1}", new Object[]{pageable.getOffset(), pageable.getPageSize()});
          q.setFirstResult(pageable.getOffset());
          q.setMaxResults(pageable.getPageSize());
      }

      // execute query
      final List<R> ret = q.getResultList();
      entityManager.close();
return ret;
  }