I've created a PagingAndSortingRepository in Spring Boot, but it does not return any results (thought it should).

The repository:

@Repository
public interface DoctorPagingRepository extends PagingAndSortingRepository<Doctor, Integer> {

    Page<Doctor> findByName(String name, Pageable pageable);
    Page<Doctor> findAllByUsername(String username, Pageable pageable);
    Page<Doctor> findAllByName(String name, Pageable pageable);
    Page<Doctor> findAllByNameContaining(String name, Pageable pageable);
}

I have other repositories which work, when not using Pageable methods i.e.

@Repository
public interface UserPagingRepository extends PagingAndSortingRepository<User, Integer> {
    User findByUsername(String username);
    User findByEmail(String email);
}

But anytime I attempt to user pageable repository methods it does work:

    @GetMapping("get-doctor/name/{name}/{pageNum}")
    public JsonResponse findDoctorByFirstname(@PathVariable String name, @PathVariable String pageNum) {
        //set page number and return up to 10 elements
        Pageable page = PageRequest.of(Integer.parseInt(pageNum), 10);

        //get list of users from that page
        Page<Doctor> doctorPage = userServices.getDoctorPaging().findAllByNameContaining(name, page);

        //set response object with users
        DoctorListResponse res = new DoctorListResponse();
        try {
            doctorPage.getContent().forEach( u -> {
                logger.trace(u.toString());
                res.getDoctorJsons().add(new DoctorJson(u));
                res.setSuccess(true);
            });
         } catch (Exception e) {
             res.setSuccess(false);
         }
         
         res.setTotalPages(doctorPage.getTotalPages());
         return res;
    }

Can anyone see where this might be going wrong?

CodePudding user response：

It turned out that the problem was to do with PageRequest.of() method's first parameter page is 'zero based page index', which I didn't realise. So it was returning the second page of results when pageNum was set to 1. The second page was empty as only 5 results in the database could have matched my query would be on the first page (as each page was set to hold ten results).

The solution was just to -1 from the pageNum:

Pageable page = PageRequest.of(Integer.parseInt(pageNum)-1, 10);