How to use modelMapper to convert nested classes

I think if you configure your ModelMapper as LOOSE or STANDARD it will do for you.

modelMapper = new ModelMapper();
modelMapper.getConfiguration().setMatchingStrategy(MatchingStrategies.LOOSE);

Otherwhise you could try next:

  1. You may create a converter like:

    public class ListThingToThingDTOConverter implements Converter<List<Thing>, List<ThingDTO>> {
    
    
    @Override
    public List<ThingDTO> convert(MappingContext<List<Thing>, List<ThingDTO>> context) {
        List<Thing> source = context.getSource();
        List<ThingDTO> output = new ArrayList<>();
        ...
        //Convert programmatically List<Thing> to List<ThingDTO>
        ...
    
        return output;
      }}
    
  2. Then customize a Mapping Thing to ThingDTO as next:

        public class SourceToSourceDTOMap extends PropertyMap<Thing, ThingDTO> {
              @Override
              protected void configure(){
                   using(new ListThingToThingDTOConverter()).map(source.getThings()).setThings(null);
              }
    
  3. Finally you must add SourceToSourceDTOMap to your ModelMapper as below:

    modelMapper = new ModelMapper();
    modelMapper.addMappings(new SourceToSourceDTOMap());
    

You can map like the below code by creating generics . link for reference

http://modelmapper.org/user-manual/generics/

imports :

import java.lang.reflect.Type;
import org.modelmapper.ModelMapper;
import org.modelmapper.TypeToken;

In your service or controller class:

ModelMapper modelMapper = new ModelMapper();
Type listType = new TypeToken<SourceDTO>(){}.getType();
SourceDTO sourceDTO = modelMapper.map(source,listType);