如何更新「多對多」在Hibernate中

Question

我試圖更新2代表與許多一對多的關係：

我有2類：

Supplier.java：

@Entity 
@Table(name = "Suppliers") 
public class Supplier implements Serializable { 

@Id 
String id; 
String name; 

@ManyToMany(fetch = FetchType.LAZY, cascade = CascadeType.ALL) 
@JoinTable(name = "Suppliers_Categories", joinColumns = { @JoinColumn(name = "SupplierId") }, inverseJoinColumns = { @JoinColumn(name = "CategoryId") }) 
Set<Category> categories = new HashSet<Category>(); 

@OneToMany(mappedBy = "supplier") 
Collection<Product> products; 

public Set<Category> getCategories() { 
    return this.categories; 
} 

public void setCategories(Set<Category> categories) { 
    this.categories = categories; 
} 

public String getId() { 
    return id; 
} 

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

public String getName() { 
    return name; 
} 

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

public Collection<Product> getProducts() { 
    return products; 
} 

public void setProducts(Collection<Product> products) { 
    this.products = products; 
} 
} 

Category.java：

@Entity 
@Table(name = "Categories") 
public class Category implements Serializable { 
@Id 
@GeneratedValue 
Integer id; 
String name; 
String namevn; 

@ManyToMany(mappedBy = "categories") 
Set<Supplier> suppliers = new HashSet<Supplier>(0); 

@OneToMany(mappedBy = "category") 
Collection<Product> products; 

@OneToOne 
@JoinColumn(name = "ProductFeature") 
Product featureProduct; 

public Set<Supplier> getSuppliers() { 
    return this.suppliers; 
} 

public Product getFeatureProduct() { 
    return featureProduct; 
} 

public void setFeatureProduct(Product featureProduct) { 
    this.featureProduct = featureProduct; 
} 

public String getNamevn() { 
    return namevn; 
} 

public void setNamevn(String namevn) { 
    this.namevn = namevn; 
} 

public void setSuppliers(Set<Supplier> suppliers) { 
    this.suppliers = suppliers; 
} 

public int getId() { 
    return id; 
} 

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

public String getName() { 
    return name; 
} 

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

public Collection<Product> getProducts() { 
    return products; 
} 

public void setProducts(Collection<Product> products) { 
    this.products = products; 
} 
} 

我對更新代碼的關係船舶：

public class CategoryController extends ActionSupport implements 
    ModelDriven<Category> { 

Category model = new Category(); 

public Category getModel() { 
    return model; 
} 

public void setModel(Category model) { 
    this.model = model; 
} 
@Action("/admin/category/update") 
public String update() { 
    try{ 
    Supplier s = XHibernate.load(Supplier.class, "1"); 
       if (!model.getSuppliers().contains(s)) { 
        model.getSuppliers().add(s); 
        s.getCategories().add(model); 
       } 

    Session session = XHibernate.openSession(); 
    Transaction transaction = session.beginTransaction(); 
    session.update(model); 
     transaction.commit(); 
    }catch(Exception e){ 
     transaction.rollback(); 
     e.printStackTrace(); 
    } 
    return "news"; 
} 

問題是我的代碼運行順利，沒有錯誤，但沒有更新。當我嘗試更新時，我的數據庫仍然是相同的。我的代碼有什麼問題嗎？如果您保存或更新Supplier

@Action("/admin/category/update") 
public String update() { 
Supplier s = XHibernate.load(Supplier.class, "1"); 
      if (!model.getSuppliers().contains(s)) { 
       model.getSuppliers().add(s); 
       s.getCategories().add(model); 
      } 
} 
Session session = XHibernate.openSession(); 

Transaction transaction = session.beginTransaction(); 
session.update(model); 
session.flush(); 
transaction.commit(); 
session.close(); 
} 

Answer 1

嘗試用沖洗會議之前提交事務，並關閉會話後提交事務。這意味着，您應該將cascade置於Category對象中，或者以某種方式更改邏輯以保存供應商。

更多的解釋：

修改類別對象如下：

@ManyToMany(mappedBy = "categories", cascade = CascadeType.ALL) 
Set<Supplier> suppliers = new HashSet<Supplier>(0); 

或如下修改CategoryController.update()：

session.update(s); 

Answer 2

您已經Supplier對象指定cascade，所以它被應用：任何幫助將是巨大的

Answer 3

我通過改變以下配置來解決我的問題category category：

@ManyToMany(fetch = FetchType.LAZY, cascade = CascadeType.ALL) 
@JoinTable(name = "Suppliers_Categories", joinColumns = { @JoinColumn(name = "CategoryId") }, inverseJoinColumns = { @JoinColumn(name = "SupplierId") }) 

，改變在供應商類：

@ManyToMany(mappedBy = "suppliers") 

現在worked.The問題是因爲我把從類別更新，所以我需要特定類別類的配置。