DatatableDAOImpl.java 文件源码

private long countDefault(final Specification<T> specification, final DatatableQuery<?, T> input) {
    final EntityManager entityManager = entityManagerFactory.createEntityManager();
      final CriteriaBuilder qb = entityManager.getCriteriaBuilder();
      final CriteriaQuery<Long> cq = qb.createQuery(Long.class);
      final Root<T> from = cq.from(this.entity);

      cq.select(qb.count(from));
      if (specification != null) {
          cq.where(specification.toPredicate(from, cq, qb));
      }
      final long ret = entityManager.createQuery(cq).getSingleResult();
      entityManager.close();
return ret;
  }