如何使用 Mapstruct 和 Kotlin 在另一个映射器中使用映射器？

Question

I would like to map an entity to a DTO with a nested DTO using Mapstruct , in Kotlin .

I have a first DTO defined as follow:

data class FirstDto (
    val something: String
)

This DTO is mapped in an entity and vice-versa using Mapstruct. Here is the Mapper:

@Mapper(componentModel = "spring")
interface FirstMapper {

    fun entityToDto(entity: FirstEntity): FirstDto

    fun dtoToEntity(dto: FirstDto): FirstEntity
}

And a second DTO nesting the first DTO:

data class SecondDto (
    val somethingElse: String,
    val firstDto: FirstDto
)

As for the first DTO, I define a Mapper using Mapstruct. But, I would like this mapper to use FirstMapper to map the nested DTO. So I should be using the uses property of the Mapper .

In Java , this would look like this: @Mapper(componentModel = "spring", uses = FirstMapper.class) .

How should it be implemented using Kotlin ?

Answer 1

It doesn't differ much. Purely syntax differences.

@Mapper(componentModel = "spring", uses = [FirstMapper::class])
interface SecondMapper {
   @Mapping(source = "firstEntity", target = "firstDto")
   fun entityToDto(entity: SecondEntity): SecondDto

   @Mapping(source = "firstDto", target = "firstEntity")
   fun dtoToEntity(dto: SecondDto): SecondEntity
}

Which generates

public class SecondMapperImpl implements SecondMapper {
    private final FirstMapper firstMapper = Mappers.getMapper(FirstMapper.class);

    @Override
    public SecondDto entityToDto(SecondEntity entity) {
        ...

        firstDto = firstMapper.entityToDto(entity.getFirstEntity());
        somethingElse = entity.getSomethingElse();
        SecondDto secondDto = new SecondDto(somethingElse, firstDto);
        return secondDto;
    }

    @Override
    public SecondEntity dtoToEntity(SecondDto dto) {
        ...

        firstEntity = firstMapper.dtoToEntity(dto.getFirstDto());
        somethingElse = dto.getSomethingElse();
        SecondEntity secondEntity = new SecondEntity(somethingElse, firstEntity);
        return secondEntity;
    }
}