第一個定義簡單地說，我有兩個實體，第一個是用戶，第二個是地址，每個用戶可以有一個或多個地址。這意味著，我想要用戶和地址之間的雙向 OneToMany 關系。問題我有一個具有 3 個地址的用戶（具有 3 個地址列表的用戶），當我更新用戶并刪除一些地址（具有 2 個地址列表的用戶）時，保存用戶后，地址的 fk 不會更新。我預計更新后我的新用戶有 2 個地址，但地址并未更改。簡而言之：當我從用戶更新地址表的列表時，地址表的 fk 沒有更新。用戶實體（只寫地址字段）@Entity@Table(name = TABLE_NAME)public class User {public static final String TABLE_NAME = "User";//Some Fields Like ID , name ,...@OneToMany(cascade = CascadeType.ALL, mappedBy = "user")@JsonManagedReferenceprivate List<Address> addresses;public List<Address> getAddresses() { return addresses;}public void setAddresses(List<Address> addresses) { this.addresses = addresses;}}地址實體（僅寫入用戶字段）@Entity@Table(name = TABLE_NAME)public class Address {public static final String TABLE_NAME = "ADDRESS";//Some Fields Like ID , name ,...@ManyToOne(cascade = CascadeType.ALL)@JoinColumn(name = "user_id")@JsonBackReferenceprivate User user;public User getUser() { return user;}public void setUser(User user) { this.user = user;}}服務等級@Servicepublic class UserService@AutowiredUserRepository repository;public updateUserAddress() { //Get User With Id of 1 User user = repository.findById(1L); //Get Addresses List<Address> addresses = user.getAddresses(); //Delete One Address From List addresses.remove(0); //Set New Address to User Entity user.setAddresses(addresses); //Save User repository.save(user) //It doesn't work (List of Address of user is the same and not changed)}順便說一句，我使用 Spring-data-jpa 和 Hibernate 作為 DAO 層。
1 回答
慕運維8079593
TA貢獻1876條經驗 獲得超5個贊
通過在實體removeAddress中添加方法User，您可以更新表的fk address，也可以保留行：
public void removeAddress(Address address) {
address.setUser(null); // or the value you want
}
該updateUserAddress方法應該是這樣的：
public void updateUserAddress() {
User user = repository.findById(1L);
List<Address> addresses = user.getAddresses();
Address address = addresses.get(0); //the address to be removed
user.removeAddress(address);
user.setAddresses(addresses);
repository.save(user);
}
用戶實體：
@Entity
@Table(name = "users")
public class User {
// other fields
@OneToMany(cascade = CascadeType.ALL, mappedBy = "user", fetch=FetchType.EAGER)
@JsonManagedReference
private List<Address> addresses;
// getters, setters, constructors etc.
// the remove method
public void removeAddress(Address address) {
address.setUser(null);
}
}
地址實體：
@Entity
@Table(name = "address")
public class Address {
// other fields
@ManyToOne
@JoinColumn(name = "user_id")
@JsonBackReference
private User user;
// getters, setters, constructors etc.
}
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