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")

@JsonManagedReference

private 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")

@JsonBackReference

private User user;

public User getUser() {

    return user;

}

public void setUser(User user) {

    this.user = user;

}

}

服务等级

@Service

public class UserService

@Autowired

UserRepository 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) {&nbsp; &nbsp; address.setUser(null); // or the value you want}该updateUserAddress方法应该是这样的：public void updateUserAddress() {&nbsp; &nbsp; User user = repository.findById(1L);&nbsp; &nbsp; List<Address> addresses = user.getAddresses();&nbsp; &nbsp; Address address = addresses.get(0); //the address to be removed&nbsp; &nbsp; user.removeAddress(address);&nbsp;&nbsp; &nbsp; user.setAddresses(addresses);&nbsp; &nbsp; repository.save(user);}用户实体：@Entity@Table(name = "users")public class User {&nbsp; &nbsp; // other fields&nbsp; &nbsp; @OneToMany(cascade = CascadeType.ALL, mappedBy = "user", fetch=FetchType.EAGER)&nbsp; &nbsp; @JsonManagedReference&nbsp; &nbsp; private List<Address> addresses;&nbsp; &nbsp; // getters, setters, constructors etc.&nbsp; &nbsp; // the remove method&nbsp; &nbsp; public void removeAddress(Address address) {&nbsp; &nbsp; &nbsp; &nbsp; address.setUser(null);&nbsp; &nbsp; }}地址实体：@Entity@Table(name = "address")public class Address {&nbsp; &nbsp; // other fields&nbsp; &nbsp; @ManyToOne&nbsp; &nbsp; @JoinColumn(name = "user_id")&nbsp; &nbsp; @JsonBackReference&nbsp; &nbsp; private User user;&nbsp; &nbsp; // getters, setters, constructors etc.}