How to map Page to Page in spring-data-rest

Question

When I hit the database with PagingAndSortingRepository.findAll(Pageable) I get Page. However, I want to expose DTO\'s to the clien

Answer 1

I am created and using solution with model mapper, generics and lambdas for common usage.

/**
 * Maps the Page {@code entities} of T type which have to be mapped as input to {@code dtoClass} Page
 * of mapped object with D type.
 *
 * @param  - type of objects in result page
 * @param  - type of entity in entityPage
 * @param entities - page of entities that needs to be mapped
 * @param dtoClass - class of result page element
 * @return page - mapped page with objects of type D.
 * @NB dtoClass must has NoArgsConstructor!
 */
public  Page mapEntityPageIntoDtoPage(Page entities, Class dtoClass) {
    return entities.map(objectEntity -> modelMapper.map(objectEntity, dtoClass));
} 

This is exactly the case which you need (and I think common case for wide range of other cases).

You already have the data obtained from repository (same is with service) on this way:

Page entities = objectEntityRepository.findAll(pageable);

Everything what you need for conversion is to call this method on this way:

Page dtoPage = mapEntityPageIntoDtoPage(entities, ObjectDto.class);

@Tip: You can use this method from util class, and it can be reused for all entity/dto in Page conversions on services and controllers according to your architecture.

Example:

Page dtoPage = mapperUtil.mapEntityPageIntoDtoPage(entities, ObjectDto.class);