I'm using spring data (mongoDb) and I've got my repository:
public interface StoriesRepository extends PagingAndSortingRepository<Story, String> {}
Then i have a controller:
@RequestMapping(method = RequestMethod.GET)
public ResponseEntity<Page<StoryResponse>> getStories(Pageable pageable) {
Page<StoryResponse> stories = storiesRepository.findAll(pageable).map(StoryResponseMapper::toStoryResponse);
return ResponseEntity.ok(stories);
}
Everything works fine, but I can't consume my endpoint using RestTemplate getForEntity method:
def entity = restTemplate.getForEntity(getLocalhost("/story"), new TypeReference<Page<StoryResponse>>(){}.class)
What class should I provide to successfully deserialize my Page of entities?
new TypeReference<Page<StoryResponse>>() {}
The problem with this statement is that Jackson cannot instantiate an abstract type. You should give Jackson the information on how to instantiate Page
with a concrete type. But its concrete type, PageImpl
, has no default constructor or any @JsonCreator
s for that matter, so you can not use the following code either:
new TypeReference<PageImpl<StoryResponse>>() {}
Since you can't add the required information to the Page
class, It's better to create a custom implementation for Page
interface which has a default no-arg constructor, as in this answer. Then use that custom implementation in type reference, like following:
new TypeReference<CustomPageImpl<StoryResponse>>() {}
Here are the custom implementation, copied from linked question:
public class CustomPageImpl<T> extends PageImpl<T> {
private static final long serialVersionUID = 1L;
private int number;
private int size;
private int totalPages;
private int numberOfElements;
private long totalElements;
private boolean previousPage;
private boolean firstPage;
private boolean nextPage;
private boolean lastPage;
private List<T> content;
private Sort sort;
public CustomPageImpl() {
super(new ArrayList<>());
}
@Override
public int getNumber() {
return number;
}
public void setNumber(int number) {
this.number = number;
}
@Override
public int getSize() {
return size;
}
public void setSize(int size) {
this.size = size;
}
@Override
public int getTotalPages() {
return totalPages;
}
public void setTotalPages(int totalPages) {
this.totalPages = totalPages;
}
@Override
public int getNumberOfElements() {
return numberOfElements;
}
public void setNumberOfElements(int numberOfElements) {
this.numberOfElements = numberOfElements;
}
@Override
public long getTotalElements() {
return totalElements;
}
public void setTotalElements(long totalElements) {
this.totalElements = totalElements;
}
public boolean isPreviousPage() {
return previousPage;
}
public void setPreviousPage(boolean previousPage) {
this.previousPage = previousPage;
}
public boolean isFirstPage() {
return firstPage;
}
public void setFirstPage(boolean firstPage) {
this.firstPage = firstPage;
}
public boolean isNextPage() {
return nextPage;
}
public void setNextPage(boolean nextPage) {
this.nextPage = nextPage;
}
public boolean isLastPage() {
return lastPage;
}
public void setLastPage(boolean lastPage) {
this.lastPage = lastPage;
}
@Override
public List<T> getContent() {
return content;
}
public void setContent(List<T> content) {
this.content = content;
}
@Override
public Sort getSort() {
return sort;
}
public void setSort(Sort sort) {
this.sort = sort;
}
public Page<T> pageImpl() {
return new PageImpl<>(getContent(), new PageRequest(getNumber(),
getSize(), getSort()), getTotalElements());
}
}