Styjun

I am having a DTOs class which is extending spring-hateoas's ResourceSupport class. The UserMinimalDto is a DTO for User entity.

So, for generating the mapper classes, I am using mapStruct.

@Data //from lambok
@EqualsAndHashCode(callSuper=false)
public class UserMinimalDto extends ResourceSupport 

 String firstName;
 String lastName;
 String email;
 String uniqueId;
 String profilePicUrl;

I am using ResourceSupport to add hateoas links to the response from the controller.

The Mapper interface

@Mapper
public interface UserMinimalMapper 

 UserMinimalMapper INSTANCE = Mappers.getMapper(UserMinimalMapper.class) ;

 UserMinimalDto entityToDto(User user);

 User dtoToEntity(UserMinimalDto userMinimalDto);

But when I run mvn clean install on the project, I am facing compilation error

Can't map property "org.springframework.hateoas.Link id" to
"java.lang.Integer id". Consider to declare/implement a mapping
method: "java.lang.Integer map(org.springframework.hateoas.Link
value)".

This is because the mapStruct is trying the map the fields of ResourceSupport.
Its works if:

1. I remove extends ResourceSupport from UserMinimalDto


2. I remove dtoToEntity(UserMinimalDto userMinimalDto); from mapper
   interface

What would be the configuration to tell mapStruct to not map the super class fields?

In order to ignore fields on a case by case bases you can use Mapping#ignore.

In your case it will look like:

@Mapper
public interface UserMinimalMapper 

 UserMinimalMapper INSTANCE = Mappers.getMapper(UserMinimalMapper.class) ;

 UserMinimalDto entityToDto(User user);

 @Mapping(target = "id", ignore = true)
 @Mapping(target = "links", ignore = true)
 User dtoToEntity(UserMinimalDto userMinimalDto);

In case you have a common interface / class for your entities you can use @MapperConfig and define those exclusions.

It can look something like:

@MapperConfig(mappingInheritanceStrategy = MappingInheritanceStrategy.AUTO_INHERIT_FROM_CONFIG)
public interface CommonMappingConfig 

 @Mapping(target = "id", ignore = true)
 @Mapping(target = "links", ignore = true)
 BaseEntity map(ResourceSupport resourceSupport);



@Mapper(config = CommonMappingConfig.class)
public interface UserMinimalMapper 

 UserMinimalMapper INSTANCE = Mappers.getMapper(UserMinimalMapper.class) ;

 UserMinimalDto entityToDto(User user);

 User dtoToEntity(UserMinimalDto userMinimalDto);

It's because the model class has other set of fields than DTO, and your mapper maps both ways. But that is pretty natural, dto doesn't have an id.

The workaround would be to exclude those fields from mapping for example by annotating id and other fields in model class, that aren't in dto with: Mapping("this").