休息控制器响应页面 <ObjectDto> 返回空对象

Question

I have used Spring Data Pageable to implement paging and sorting. My relevant code snippet is:

    //GET API designed as POST due to Request Body, in lines of ES APIs
    @PostMapping(value = "/v2")
    public Page<ObjectDto> getObjects(@RequestBody @Valid Map<Integer, FilterRequestDto> filterDtoMap, Pageable pageable) {
        Page<ObjectDto> objectDtos = myService.getDtos(filterDtoMap, pageable);
        log.info(String.valueOf(objectDtos.getTotalElements()));
        return objectDtos;
    }

Although I have data(confirmed from the log), the above API is responding with {} .

However, when I am returning List like in this snippet:

    @PostMapping(value = "/v2")
    public List<ObjectDto> getObjects(@RequestBody @Valid Map<Integer,FilterRequestDto> filterDtoMap, Pageable pageable) {
        Page<ObjectDto> objectDtos = myService.getDtos(filterDtoMap, pageable);
        log.info(String.valueOf(objectDtos.getTotalElements()));
        return objectDtos.getContent();
    }

Response for List return type for the exact same API is a proper response as expected:

[ { "sellingPrice": 23000, "id": 1, "version": 1, "createdOn": "25 Feb 2019,05:53", "lastUpdatedOn": "25 Feb 2019,05:53" } ]

Repository Code:

@Repository
public interface MyObjectRepository extends JpaRepository<MyObject, Long>, JpaSpecificationExecutor<MyObject> {}

Service Code:

public Page<ObjectDto> getTyres(Map<Integer, FilterRequestDto> filterDtoMap, Pageable pageable) {
        List<FilterDto> filterDtoList = filtersService.getAllFiltersById(filterDtoMap.keySet());
        return objectMapper.toDto(myObjectRepository.findAll(ObjectSpecs.filter(filterDtoList, filterDtoMap), pageable));
    }

As far as I know, we can return page as a Rest API response, so what can be the issue here? Any help will be much appreciated.

Answer 1

Don't use Page<ObjectDto> as return type of rest methods. This Page is not for that. use return type as List<ObjectDto>

and in log you are printing

log.info(String.valueOf(objectDtos.getTotalElements()));

so its printing properly, if you return objectDtos.getTotalElements() in rest method then it will also work