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Explanation

Pagination is used to retrieve large datasets in smaller chunks. Instead of returning all records at once, the API returns a specific page of data. Spring Data JPA provides built-in support for pagination using Pageable.

Code:

import org.springframework.data.jpa.
repository.JpaRepository;

public interface StudentRepository 
extends JpaRepository<Student, Long> {
}

Explanation

The Pageable interface allows clients to specify the page number and page size. Spring automatically creates a Pageable object from request parameters.

Code:

@GetMapping("/students")
public Page<Student> getStudents(
Pageable pageable) {
    return studentRepository.findAll(
pageable);
}

Explanation

Pagination can be controlled explicitly using page and size query parameters. The PageRequest class creates a Pageable instance with the desired settings.

Code:

@GetMapping("/students")
public Page<Student> getStudents(
        @RequestParam int page,
        @RequestParam int size) {

    Pageable pageable =
 PageRequest.of(page, size);
    return studentRepository.findAll(
pageable);
}

Explanation

Sorting allows records to be returned in ascending or descending order based on a field. The Sort class is used to define sorting criteria.

Code:

@GetMapping("/students/sorted")
public List<Student> getSortedStudents() {
    return studentRepository.findAll(
            Sort.by("name").ascending()
    );
}

Explanation

Pagination and sorting can be combined to efficiently retrieve ordered data. This is commonly used in production APIs to improve performance and user experience.

Code:

@GetMapping("/students/paged")
public Page<Student> getPagedStudents(
        @RequestParam int page,
        @RequestParam int size) {

    Pageable pageable = PageRequest.of(
            page,
            size,
            Sort.by("name").descending()
    );

    return studentRepository.
findAll(pageable);
}