I want to map the mulitple fields of the Dto class to single field of entity and vice versa. How to achieve this?

Question

So here, we have a Enitity class - Contact

public class Contact {
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Long id;
    @Column(name = "name",nullable = false)
    private String name;
    @Column(name = "email",nullable = false,unique = true)
    private String email;
    @Column(name = "phone",nullable = false)
    private String phone;
}

A DTO class - ContactDto

public class ContactDto {
    private Long id;
    private String fname;
    private String lname;
    private String email;
    private String phone;
}

I want to map the fname and lname with the name attribute in the contact and vice versa. How to achieve this solution?

I tried using MapStruct library. I am getting confused how to implement this logic. So kindly help me either with MapStruct or ModelMapper.

@Mapper
public interface ContactMapper {
    ContactMapper INSTANCE = Mappers.getMapper(ContactMapper.class);
    ContactDto mapToContactDto(Contact contact);
    Contact mapToContact(ContactDto contactDto);
}

This is what i tried doing using Mapstruct.

Answer 1

I recommend to read this question. how-to-convert-entity-to-dto-and-vice-versa

If you want to continue using MapStruct here is good explanation. Baeldung - mapstruct

Usually it is better to write your own mapper, becuase you have full controll what is happening and have less headache if some tests stop working in future.

Personally I would do like this: Of Method in Mapper

Answer 2

You can make use of custom mapping rules in ModelMapper, create TypeMap and pass Contact and ContacoDTO as arguments. Sample code could be like:

ModelMapper modelMapper = new ModelMapper();
TypeMap<Contact , ContactDto > typeMap =     modelMapper.createTypeMap(Contact.class, ContactDto.class);
typeMap.addMappings(mapper -> {
    mapper.map(src -> src.getFirstName() + " " + src.getLastName(), ContactDto::setFullName);
});

Answer 3

To do this with MapStruct, your best bet will probably be to define a custom method for each conversion with @BeforeMapping annotation. This also requires that you change your interface to an abstract class.

@Mapper
public abstract class ContactMapper {
    ContactMapper INSTANCE = Mappers.getMapper(ContactMapper.class);
    mapToContactDto(Contact contact);
    Contact mapToContact(ContactDto contactDto);

    @BeforeMapping
    protected void splitName(Contact contact, @MappingTarget ContactDto contactDto) {
        String[] name = contact.getName().split(“ “);
        contactDto.setFname(name[0]);
        contactDto.setLname(name[1]);
    }

    @BeforeMapping
    protected void concatenateName(ContactDto contactDto, @MappingTarget Contact contact) {
        contact.setName(contactDto.getFname() + “ “ + contactDto.getLname());
    }
}

This is assuming the name is in “First Last” format in Contact. Also assumes Contact and ContactDto have standard getter/setter methods.