JPA sorting query result after querying with Pageable - spring-boot

Question

I am having an #Entity like this:
import java.time.LocalDateTime;
import javax.persistence.Entity;
import lombok.AllArgsConstructor;
import lombok.Data;
import lombok.NoArgsConstructor;
import org.springframework.data.jpa.domain.AbstractPersistable;
#Entity
#Data#NoArgsConstructor#AllArgsConstructor
public class Message extends AbstractPersistable<Long> {
private LocalDateTime messageDate = LocalDateTime.now();
private String message;
}
And a repository like this:
import java.util.List;
import org.springframework.data.domain.Pageable;
import org.springframework.data.jpa.repository.JpaRepository;
public interface MessageRepository extends JpaRepository<Message, Long> {
//List<Message> findAllByOrderByMessageDateAsc(Pageable pageable);
// With this I am trying to re-sort what I get
}
And a #Controller
#GetMapping("/messages")
public String list(Model model) {
Pageable limit = PageRequest.of(0, 5, Sort.by("messageDate").descending());
model.addAttribute("messages", messageRepository.findAll(limit));
//model.addAttribute("messages", messageRepository.findAllByOrderByMessageDateAsc(limit));
return "messages";
}
I get five latest messages in descending order. But how do I get them in ascending order?

Answer 1

What you need is the last 5 messages in ascending order by massage date.
Two ways to solve it.
Using Custom implementation of Pageable
You can't use offset properly for PageRequest. So,
you need to use a custom implementation of Pageable for offset.
You can use custom implementation OffsetBasedPageRequest. Then use it this way.
int totalCount = (int)serviceRepository.count();
Pageable pageable = new OffsetBasedPageRequest(totalCount - limit, limit, Sort.by("messageDate"));
messageRepository.findAll(pageable);
After fetching Sort Page data
You can get the list from Page<T> using page.getContent() then sort manually the list.
Pageable pageable = PageRequest.of(0, limit, Sort.by("messageDate").descending());
List<Message> list = messageRepository.findAll(pageable ).getContent();
List<Message> sorted =list.stream().sorted(Comparator.comparing(r -> r.getMessageDate())).collect(Collectors.toList());
Then again you have to create Page<Massage> if you want.