当孩子更新时如何更新jpa中双向关系所有者的fk

Question

第一个定义简单地说，我有两个实体，第一个是用户，第二个是地址，每个用户可以有一个或多个地址。这意味着，我想要用户和地址之间的双向 OneToMany 关系。问题我有一个具有 3 个地址的用户（具有 3 个地址列表的用户），当我更新用户并删除一些地址（具有 2 个地址列表的用户）时，保存用户后，地址的 fk 不会更新。我预计更新后我的新用户有 2 个地址，但地址并未更改。简而言之：当我从用户更新地址表的列表时，地址表的 fk 没有更新。用户实体（只写地址字段）@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;}}地址实体（仅写入用户字段）@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;}}服务等级@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)}顺便说一句，我使用 Spring-data-jpa 和 Hibernate 作为 DAO 层。

Answer 1

通过在实体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

}

该updateUserAddress方法应该是这样的：

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);

}

用户实体：

@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);

    }

}

地址实体：

@Entity

@Table(name = "address")

public class Address {

    // other fields

    @ManyToOne

    @JoinColumn(name = "user_id")

    @JsonBackReference

    private User user;

    // getters, setters, constructors etc.

}