GenericRepositoryImpl.java 文件源码

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;
}