DTO pattern: Best way to copy properties between two objects

Question

In my application\'s architecture I usually send the object or list of objects from the data access layer to the web layer via the service layer, in which these objects get

Answer 1

I had an application that I needed to convert from a JPA entity to DTO, and I thought about it and finally came up using org.springframework.beans.BeanUtils.copyProperties for copying simple properties and also extending and using org.springframework.binding.convert.service.DefaultConversionService for converting complex properties.

In detail my service was something like this:

@Service("seedingConverterService")
public class SeedingConverterService extends DefaultConversionService implements ISeedingConverterService  {
    @PostConstruct
    public void init(){
        Converter featureConverter = new Converter() {

            @Override
            public FeatureDTO convert(Feature f) {
                FeatureDTO dto = new FeatureDTO();
                //BeanUtils.copyProperties(f, dto,"configurationModel");
                BeanUtils.copyProperties(f, dto);
                dto.setConfigurationModelId(f.getConfigurationModel()==null?null:f.getConfigurationModel().getId());
                return dto;
            }
        };

        Converter configurationModelConverter = new Converter() {
            @Override
            public ConfigurationModelDTO convert(ConfigurationModel c) {
                ConfigurationModelDTO dto = new ConfigurationModelDTO();
                //BeanUtils.copyProperties(c, dto, "features");
                BeanUtils.copyProperties(c, dto);
                dto.setAlgorithmId(c.getAlgorithm()==null?null:c.getAlgorithm().getId());
                List l = c.getFeatures().stream().map(f->featureConverter.convert(f)).collect(Collectors.toList());
                dto.setFeatures(l);
                return dto;
            }
        };
        addConverter(featureConverter);
        addConverter(configurationModelConverter);
    }
}