How to skip properties in destination source in modelmapper?

Question

I have two classes. RequestDTO and Entity. I want to map RequestDTO to the Entity. In that case, I want to insert one of the Entity property manually which means that property is not in the Request DTO. How to achieve this using modelmapper.

public class RequestDTO {

    private String priceType;

    private String batchType;
}

public class Entity {


    private long id;

    private String priceType;

    private String batchType;
}

Entity newEntity = modelMapper.map(requestDto, Entity.class);

But this does not work, it says it can't convert string to long. I request a solution to this or a better approach to this.

Answer 1

If you want to perform the mapping manually (ideally for dissimilar objects)

You can check the documentation for dissimilar object mapping Property Mapping,

You can define a property mapping by using method references to match a source getter and destination setter.

typeMap.addMapping(Source::getFirstName, Destination::setName);

The source and destination types do not need to match.

 typeMap.addMapping(Source::getAge, Destination::setAgeString);

If you don't want to do the mapping field by field to avoid boilerplate code

you can configure a skip mapper, to avoid mapping certain fields to your destination model:

modelMapper.addMappings(mapper -> mapper.skip(Entity::setId));

---

I've created a test for your case and the mapping works for both side without configuring anything :

import lombok.AllArgsConstructor;
import lombok.Data;
import lombok.NoArgsConstructor;
import org.junit.Before;
import org.junit.Test;
import org.modelmapper.ModelMapper;

import static junit.framework.TestCase.assertEquals;
import static junit.framework.TestCase.assertNotNull;

public class ModelMapperTest {

    private ModelMapper modelMapper;

    @Before
    public void beforeTest() {
        this.modelMapper = new ModelMapper();
    }

    @Test
    public void fromSourceToDestination() {
        Source source = new Source(1L, "Hello");
        Destination destination = modelMapper.map(source, Destination.class);
        assertNotNull(destination);
        assertEquals("Hello", destination.getName());
    }

    @Test
    public void fromDestinationToSource() {
        Destination destination = new Destination("olleH");
        Source source = modelMapper.map(destination, Source.class);
        assertNotNull(source);
        assertEquals("olleH", destination.getName());
    }
}

@Data
@NoArgsConstructor
@AllArgsConstructor
class Source {
    private Long id;
    private String name;
}

@Data
@NoArgsConstructor
@AllArgsConstructor
class Destination {
    private String name;
}