Spring Data Pagination返回错误的内容数量

Question

currently I am developing an api which uses Spring Data Pagination and I came to the problem that I passing a Pageable object as a request to my repository with which page I want to receive and how many elements should be on it. And with that my object looks like: Pageable pageable = PageRequest.of(0, 2); - so I want first page with two elements. In my database are 3 objects so therefore there will be 2 pages. But what ide shows me is: screenshot . Can anyone tell me why it shows that content is an array of 3 elements but actually I asked for 2 elements?

   @Override
public List<NotificationDto> getLast30NotificationsFor(ApplicationUser user) {
    Pageable pageable = PageRequest.of(0, 2);
    Page<Notification> first30ByOwnerIdOrderByCreatedAtDesc = notificationRepository.findFirst30ByOwnerIdOrderByCreatedAtDesc(user.getId(), pageable);

    List<Notification> notifications = new ArrayList<>(first30ByOwnerIdOrderByCreatedAtDesc.getContent());
    return notifications.stream()
            .map(NotificationToDtoMapper::map)
            .collect(toList());
}

Answer 1

Try:

@Override
public List<NotificationDto> getLast30NotificationsFor(ApplicationUser user) {
    Pageable page = PageRequest.of(0,2, Sort.by("createdAt").descending());
    return notificationRepository.findByOwnerId(user.getId(), page)
    .getContent()
    .stream()
    .map(NotificationToDtoMapper::map)
    .collect(toList());
}