MapStruct反向鏈接映射可能嗎？

我是MapStruct的新手，無法在Google上找到我的問題的答案。我有一個購物車已獲得樣品（其他屬性），每個樣品需要一個參考返回到我的ShoppingCart。是否可以使用MapStruct進行這種映射？如果沒有MapStruct，我只需將對ShoppingCart的引用傳遞給Samples。這是手寫的：MapStruct反向鏈接映射可能嗎？

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

來源

2017-08-03 gute Fee

是由您或MapStruct創建問題的方法？ – Filip

'ShoppingCart'包含'ShoppingCartSample'（s）嗎？你有沒有想要映射的週期？你能否展示你的模型的簡化代碼？我需要這個信息，所以我可以最正確地回答這個問題，我不知道我現在是否正確理解它。 – Filip

是的，ShoppingCart包含ShoppingCarSamples。 ShoppingCartSample包含ShoppingCart。我想這可以稱爲一個循環。 –

可以使用decorator並設置自己與toher類的鏈接，通過mapstruct自動調用

您的映射

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

你的裝飾

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) 
     } 
    } 
}

來源

2017-08-04 11:24:09

這將在映射期間創建一個循環。我今天晚些時候會發佈一個應該用於映射週期的答案 – Filip

看看它使用的mapstruct-mapping-with-cycles存儲庫e新（從1.2.0）@Context映射週期（這是你有什麼）。

這裏的代碼，以及：

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); 
    } 
}

請記住，在CycleAvoidingMappingContext的source和target對象可以更具體的類型，他們並不需要爲Object。

映射器看起來像：

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

來源

2017-08-04 17:54:55 Filip

MapStruct反向鏈接映射可能嗎？

回答

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