Spring Boot JPA中仅插入Friend表不更新User表的问题求助

在处理一对多关联表插入操作时，仅希望向Friend表插入好友请求数据，但控制台输出了User表的更新语句，进而触发"password is null"错误，需要实现仅插入Friend表而不更新User表的逻辑。

User实体类 #

@Data
@NoArgsConstructor
@AllArgsConstructor
@Builder
@Entity
@Table(name = "user")
public class User {
    @Id
    @GeneratedValue(strategy = GenerationType.UUID)
    @Column(name = "id", nullable = false)
    private String id;

    @Column(name = "name", nullable = false)
    private String name;

    @Column(name = "email", nullable = false, unique = true)
    @Email
    private String email;

    @Column(name = "password", nullable = false)
    private String password;

    @Column(name = "avatar")
    private String avatar;

    @Column(name = "gender", nullable = false)
    private String gender;

    @Column(name = "phone")
    private String phone;

    @Temporal(TemporalType.DATE)
    @Column(name = "birth_date", nullable = false)
    private Date birthDate;

    @OneToMany(mappedBy = "user", cascade = CascadeType.ALL, fetch = FetchType.LAZY)
    @JsonIgnore
    private List<UserRoom> userRooms;

    @OneToMany(mappedBy = "myself", cascade = CascadeType.ALL, fetch = FetchType.LAZY)
    @JsonIgnore
    private List<Friend> myself;

    @OneToMany(mappedBy = "friend", cascade = CascadeType.ALL, fetch = FetchType.LAZY)
    @JsonIgnore
    private List<Friend> friend;
}

Friend实体类 #

@Data
@NoArgsConstructor
@Getter
@Setter
@ToString
@AllArgsConstructor
@Builder
@Entity
@Table(name = "friend", uniqueConstraints = {
        @UniqueConstraint(columnNames = {"myself_id", "friend_id"})
})
public class Friend {

    @Id
    @GeneratedValue(strategy = GenerationType.UUID)
    @Column(nullable = false)
    private String id;

    @NotNull
    @ManyToOne(fetch = FetchType.LAZY, cascade = CascadeType.PERSIST)
    @JoinColumn(name = "myself_id")
    @JsonIgnore
    private User myself;

    @NotNull
    @ManyToOne(fetch = FetchType.LAZY, cascade = CascadeType.PERSIST)
    @JoinColumn(name = "friend_id")
    @JsonIgnore
    private User friend;

    @Enumerated(EnumType.STRING)
    @Column(name = "relationship", nullable = false)
    private Relationship relationship;

    public enum Relationship {
        NONE,
        SEND_REQUEST,
        RECEIVE_REQUEST,
        FRIEND,
        BLOCKED,
    }
}

FriendServiceImpl业务实现类 #

@Override
public Object sendFriendRequest(JsonNode info) {
    String friendId = info.get("friendId").textValue();
    String myId = info.get("myId").textValue();

    User friendInfo = userService.findUserInformationById(friendId);
    User myInfo = userService.findUserInformationById(myId);

    System.out.println(">>>" + friendInfo + " \n" + myInfo);
    if(friendInfo == null || myInfo == null) {
        return null;
    }

    Friend a = new Friend().builder()
                    .myself(friendInfo)
                    .friend(myInfo)
                    .relationship(Friend.Relationship.RECEIVE_REQUEST)
                    .build();
    Object yourNewRelationship = friendRepository.save(a);
    System.out.println("OKOKOK");
    Object myNewRelationship = friendRepository.save(
            new Friend().builder()
                    .myself(myInfo)
                    .friend(friendInfo)
                    .relationship(Friend.Relationship.SEND_REQUEST)
                    .build()
    );
    return myNewRelationship;
}

控制台输出 #

数据库表结构 #

解决方法 #

问题根源 #

1. User实体中myself和friend两个@OneToMany关联配置了cascade = CascadeType.ALL，当Friend实体被持久化时，会级联触发User实体的更新操作。
2. 从userService.findUserInformationById获取的User对象可能未正确加载password字段（比如查询时未包含该字段、DTO转实体时丢失），导致JPA认为User的password被修改为null，触发更新时违反非空约束。

修复步骤 #

1. 调整User实体的级联策略
   将myself和friend的级联策略改为CascadeType.PERSIST，或直接移除级联配置（因为Friend表插入不需要操作已存在的User表）：

   @OneToMany(mappedBy = "myself", cascade = CascadeType.PERSIST, fetch = FetchType.LAZY)
   @JsonIgnore
   private List<Friend> myself;
   
   @OneToMany(mappedBy = "friend", cascade = CascadeType.PERSIST, fetch = FetchType.LAZY)
   @JsonIgnore
   private List<Friend> friend;
   

   若不需要任何级联操作，可设置为cascade = {}：

   @OneToMany(mappedBy = "myself", cascade = {}, fetch = FetchType.LAZY)
   @JsonIgnore
   private List<Friend> myself;
   

2. 确保User对象的必填字段完整
   检查userService.findUserInformationById的实现，确保查询User时加载了所有必填字段（包括password），避免返回的User实体存在null的必填属性。

3. 可选：分离持久化上下文的User实体
   若必须保留级联策略，可在保存Friend前将User实体从持久化上下文分离，阻止JPA跟踪其状态变化：

   entityManager.detach(friendInfo);
   entityManager.detach(myInfo);
   

内容的提问来源于stack exchange，提问作者An Nguyen