mapstruct

Multi-layered applications often require to map between different object models (e.g. entities and DTOs)

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https://mapstruct.org/

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DTO와 Entity class의 변수값을 mapping해줄 때 사용하는 것 같다.

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gradle

dependencies {
    ...
    implementation 'org.mapstruct:mapstruct:1.5.3.Final'

    annotationProcessor 'org.mapstruct:mapstruct-processor:1.5.3.Final'
}

reference guide

https://mapstruct.org/documentation/stable/reference/html/

MapStruct 1.5.3.Final Reference Guide

Preface This is the reference documentation of MapStruct, an annotation processor for generating type-safe, performant and dependency-free bean mapping code. This guide covers all the functionality provided by MapStruct. In case this guide doesn’t answer all your questions just join the MapStruct Gi…

@Mapping 애노테이션을 사용해서 작성하는 것으로 보이고, build-time에 구현체가 생성되는 것 같다.

@Mapper
public interface CarMapper {

    @Mapping(target = "manufacturer", source = "make")
    @Mapping(target = "seatCount", source = "numberOfSeats")
    CarDto carToCarDto(Car car);

    @Mapping(target = "fullName", source = "name")
    PersonDto personToPersonDto(Person person);
}

구현 코드는 다음과 같이 만들어지는 것 같다.

// GENERATED CODE
public class CarMapperImpl implements CarMapper {

    @Override
    public CarDto carToCarDto(Car car) {
        if ( car == null ) {
            return null;
        }

        CarDto carDto = new CarDto();

        if ( car.getFeatures() != null ) {
            carDto.setFeatures( new ArrayList( car.getFeatures() ) );
        }
        carDto.setManufacturer( car.getMake() );
        carDto.setSeatCount( car.getNumberOfSeats() );
        carDto.setDriver( personToPersonDto( car.getDriver() ) );
        carDto.setPrice( String.valueOf( car.getPrice() ) );
        if ( car.getCategory() != null ) {
            carDto.setCategory( car.getCategory().toString() );
        }
        carDto.setEngine( engineToEngineDto( car.getEngine() ) );

        return carDto;
    }

    @Override
    public PersonDto personToPersonDto(Person person) {
        //...
    }

    private EngineDto engineToEngineDto(Engine engine) {
        if ( engine == null ) {
            return null;
        }

        EngineDto engineDto = new EngineDto();

        engineDto.setHorsePower(engine.getHorsePower());
        engineDto.setFuel(engine.getFuel());

        return engineDto;
    }
}

그 밖의 설정들은 많이 있는 것으로 보인다. reference 문서를 참고해보자.

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product class

public class Product {
    private int productId;
    private String name;
    private int weight;
    private String serviceAddress;

    public Product() {
        productId = 0;
        name = null;
        weight = 0;
        serviceAddress = null;
    }

    public Product(int productId, String name, int weight, String serviceAddress) {
        this.productId = productId;
        this.name = name;
        this.weight = weight;
        this.serviceAddress = serviceAddress;
    }

    public int getProductId() {
        return productId;
    }

    public String getName() {
        return name;
    }

    public int getWeight() {
        return weight;
    }

    public String getServiceAddress() {
        return serviceAddress;
    }

    public void setProductId(int productId) {
        this.productId = productId;
    }

    public void setName(String name) {
        this.name = name;
    }

    public void setWeight(int weight) {
        this.weight = weight;
    }

    public void setServiceAddress(String serviceAddress) {
        this.serviceAddress = serviceAddress;
    }
}

product mapper class

@Mapper(componentModel = "spring")
public interface ProductMapper {

    @Mappings({
        @Mapping(target = "serviceAddress", ignore = true)
    })
    Product entityToApi(ProductEntity entity);

    @Mappings({
        @Mapping(target = "id", ignore = true),
        @Mapping(target = "version", ignore = true)
    })
    ProductEntity apiToEntity(Product api);
}

product entity class

@Document(collection="products")
public class ProductEntity {

    @Id
    private String id;

    @Version
    private Integer version;

    @Indexed(unique = true)
    private int productId;

    private String name;
    private int weight;

    public ProductEntity() {
    }

    public ProductEntity(int productId, String name, int weight) {
        this.productId = productId;
        this.name = name;
        this.weight = weight;
    }

    public String getId() {
        return id;
    }

    public Integer getVersion() {
        return version;
    }

    public int getProductId() {
        return productId;
    }

    public String getName() {
        return name;
    }

    public int getWeight() {
        return weight;
    }

    public void setId(String id) {
        this.id = id;
    }

    public void setVersion(Integer version) {
        this.version = version;
    }

    public void setProductId(int productId) {
        this.productId = productId;
    }

    public void setName(String name) {
        this.name = name;
    }

    public void setWeight(int weight) {
        this.weight = weight;
    }
}

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