@Override
 public Page<Comment> findAllPagedByID(Long id, int pagenum, int size) {
   return commentRepository.findAllByPost_PostId(id, new PageRequest(pagenum, size));
 }
 @Override
 public Comment save(Comment comment) {
   return commentRepository.save(comment);
 }
 @Override
 public Long countByPost(Post post) {
   return commentRepository.countByPost(post);
 }