Paginación y ordenación

Why Paginate

PagingAndSortingRepository

public interface UserRepository
    extends JpaRepository<User, Long> {
}

Creating a Pageable

Pageable pageable = PageRequest.of(0, 20);
Page<User> page = userRepository.findAll(pageable);

The Page Object

List<User> content = page.getContent();
long total = page.getTotalElements();
int pages = page.getTotalPages();
boolean hasNext = page.hasNext();

Sorting

Sort sort = Sort.by("name").ascending();
List<User> sorted = userRepository.findAll(sort);

Combining Sort and Paging

Pageable pageable = PageRequest.of(
    0, 20, Sort.by("name").descending());
Page<User> page = userRepository.findAll(pageable);

Multiple Sort Orders

Sort sort = Sort.by(
    Sort.Order.asc("lastName"),
    Sort.Order.desc("createdAt"));

Paging Derived Queries

Page<User> findByActiveTrue(Pageable pageable);

Slice vs Page

Slice<User> findByActiveTrue(Pageable pageable);

Pageable from the Web Layer

@GetMapping("/users")
public Page<User> list(Pageable pageable) {
    return userRepository.findAll(pageable);
}
// GET /users?page=0&size=20&sort=name,desc

Mapping Page Content to DTOs

Page<UserDto> dtos = page.map(
    user -> new UserDto(user.getName(), user.getEmail()));

Quick Check

Recap