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MapStruct反向链接映射是否可行?

mapstruct java

user3832429 · 技术社区 · 7 年前

我是MapStruct的新手,在谷歌上找不到问题的答案。我有一个ShoppingCart,它有样本(以及其他属性),每个样本都需要一个对我的ShoppingCart的引用。可以用MapStruct进行这样的映射吗? 没有MapStruct,我只需将对ShoppingCart的引用传递给示例。这是手写的:

protected ShoppingCart map(Cart cart, DataShareOption dataShareOption) {
//(other stuff)
   for (CartSample cartSample : cart.getCartSamples()) {
       ShoppingCartSample sample = mapCartSample(cartSample, shoppingCart,
       dataShareOption);
       shoppingCart.getSamples().add(sample);
   }
}

protected ShoppingCartSample mapCartSample(CartSample cartSample,
    ShoppingCart shoppingCart, DataShareOption dataShareOption) {

     ShoppingCartSample sample = new ShoppingCartSample();
     sample.setShoppingCart(shoppingCart);
     //(other stuff)
     return sample;
}

// the classes declarations:
// business class
public class ShoppingCart extends ShoppingCartHeader
{
    private List<ShoppingCartSample> samples = new   ArrayList<ShoppingCartSample>();
//rest of the class


// data base class:
@Entity
@Table(name = "cart")
public class Cart extends BaseEntity
{
@OneToMany(cascade = CascadeType.ALL, orphanRemoval = true, mappedBy = "cart")
private Set<CartSample> cartSamples = new HashSet<CartSample>();
   // more stuff here


// business class:
  public class ShoppingCartSample
  {
   private ShoppingCart shoppingCart;
  // rest of the class


// data base class:
@Entity
@Table(name = "cart_sample")
public class CartSample
{
   @ManyToOne()
   @JoinColumn(name = "cart_id")
   private Cart cart;
   // more stuff here

3 回复 | 直到 7 年前

Tomer Gal 6 年前

您可以使用 @AfterMapping 注释如下:

@Mapper
public interface ShoppingCartMapper{
    ShoppingCart map(Cart cart);
    ShoppingCartSample map(CartSample cartSample);

    @AfterMapping
    default void setShoppingCartSampleParent(@MappingTarget ShoppingCart cart){
        for(ShoppingCartSample cartSample : cart.getSamples()){
            cartSample.setShoppingCart(cart);
        }
    }
}

Bertrand Cedric 7 年前

您可以使用 decorator 并使用toher类设置链接,通过mapstruct自动调用

您的映射器

@Mapper
@DecoratedWith(MyMapperDecorator.class)
public interface MyMapper {
    ShoppingCart map(Cart cart);
    ShoppingCartSample map(CartSample cart);
}

public abstract class MyMapperDecorator implements MyMapper {
    private final MyMapper delegate;

    public ParticulierMapperDecorator(MyMapper delegate) {
        this.delegate = delegate;
    }

    public ShoppingCart map(Cart cart){
        ShoppingCart shoppingCart = delegate.map(cart);//map the two objects
        //Set your link
        for(ShoppingCartSample sample: hoppingCart.getSampes()){
            sample.setShoppingCart(shoppingCart)
        }
    }
}

Filip 7 年前

看一看 mapstruct-mapping-with-cycles @Context 映射周期(这是您拥有的)。

这里的代码也是:

public class CycleAvoidingMappingContext {
    private Map<Object, Object> knownInstances = new IdentityHashMap<Object, Object>();
    @BeforeMapping
    public <T> T getMappedInstance(Object source, @TargetType Class<T> targetType) {
        return (T) knownInstances.get( source );
    }
    @BeforeMapping
    public void storeMappedInstance(Object source, @MappingTarget Object target) {
        knownInstances.put( source, target );
    }
}

请记住 source target CycleAvoidingMappingContext Object .

映射器看起来像:

@Mapper
public interface MyMapper {
    ShoppingCart map(Cart cart, @Context CycleAvoidingMappingContext context);
    ShoppingCartSample map(CartSample cart, @Context CycleAvoidingMappingContext context);
}