Nested Property

The original idea is from https://www.tutorialspoint.com/mapstruct/mapstruct_mapping_nested_bean.htm

Ignore Property

The original idea is from

https://medium.com/@nina.trausner/mapstruct-different-approaches-and-best-practices-282adbb96838

@AfterMapping

The original idea is from
https://raphaeldelio.medium.com/aftermapping-updating-lists-or-custom-objects-with-mapstruct-in-java-4a6f4622ef92

Expressions and Default Values

The original idea is from
https://medium.com/@tecnicorabi/mastering-mapstruct-for-efficient-java-bean-mappings-f03ddd9b511b

source and target

@Mapper
public interface ProductMapper {

  @Mapping(source = "priceEuro", target = "price")
  Product productDTOToProduct(ProductDTO productDTO);
}

ignore

@Mapper
public interface UserMapper {
  @Mapping(target = "id", ignore = true)
  UserDTO createUserDTOWithoutId(User user);
}

expression

@Mapper
public interface ProductMapper {
   @Mapping(target = "totalPrice", expression = "java(product.getPrice() * 1.08)")
   ProductDTO productToProductDTO(Product product);
}

lists

@Mapper
public interface ProductMapper {
  List<ProductDTO> productsToProductDTOs(List<Product> products);
}

Nested Mapping

@Mapper(uses = ProductMapper.class)
public interface OrderMapper {
    OrderDTO orderToOrderDTO(Order order);
}

Enum Mapping

@Mapper
public interface OrderMapper {
  OrderDTO orderToOrderDTO(Order order);

  @ValueMappings({
    @ValueMapping(source = "PROCESSING", target = "PENDING"),
    @ValueMapping(source = "SHIPPED", target = "COMPLETED"),
    @ValueMapping(source = "DELIVERED", target = "CANCELLED")
  })
  OrderStatusDTO mapOrderStatusToOrderStatusDTO(OrderStatus orderStatus);
}

Mapping with Null Handling

@Mapper
public interface ProductMapper {
  @Mapping(target = "price", source = "price", defaultValue = "0.0")
  ProductDTO productToProductDTO(Product product);
}

Mapping with Custom Converters

@Mapper
public interface ProductMapper {

  @Mapping(target = "manufactureDate", source = "manufactureDate", qualifiedByName = "stringToLocalDate")
  Product productDTOToProduct(ProductDTO productDTO);

  @Named("stringToLocalDate")
  default LocalDate stringToLocalDate(String date) {
    return LocalDate.parse(date);
  }
}