休眠JPA父母與子組合違反父子女

Question

我在創建父對象和子對象時遇到了問題，並在使用JPA和休眠的情況下將其持久保存到數據庫中。父類看起來像這樣：

@Entity 
@Table(name = "PUser") 
public final class User { 

    @Id 
    @Column(name = "ID", unique = true, nullable = false, updatable = false) 
    @GeneratedValue(strategy = GenerationType.AUTO) 
    private long id; 

} 

的子對象使用的化合物鍵，場是父的ID之一：

@Entity 
@Table(name = "PAttribute") 
public final class Attribute { 

    @EmbeddedId 
    @AttributeOverrides({ 
        @AttributeOverride(name = "domain", column = @Column(name = "domain", nullable = false, length = 128)), 
        @AttributeOverride(name = "name", column = @Column(name = "name", nullable = false, length = 128)), 
        @AttributeOverride(name = "userid", column = @Column(name = "userid", nullable = false)) }) 
    private AttributePk pk; 

    @ManyToOne(fetch = FetchType.LAZY) 
    @JoinColumn(name = "userid", nullable = false, insertable = false, updatable = false) 
    private User user; 

} 

複合鍵類之中：

@Embeddable 
    public class AttributePk implements java.io.Serializable { 

      private static final long serialVersionUID = -7003721226789641149L; 

      @Column(nullable = false, length = 128) 
      private String domain; 

      @Column(nullable = false, length = 128) 
      private String name; 

      @Column(nullable = false) 
      private long userid; 

    } 

現在，當我創建一個新用戶並添加一個附件，然後嘗試保存該對象圖時

User user = new User("joe1.bloggs@ft.com", "xyz"); 
    user.setScreenName("joe1bloggs"); 
    user.addAttribute("domain", "name", 212); 

    target.saveAndFlush(user); 

我得到的異常

Caused by: com.mysql.jdbc.exceptions.jdbc4.MySQLIntegrityConstraintViolationException: Cannot add or update a child row: a foreign key constraint fails (`fta_portal_user/PAttribute`, CONSTRAINT `userId` FOREIGN KEY (`userid`) REFERENCES `PUser` (`id`) ON DELETE NO ACTION ON UPDATE NO ACTION) 
    at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method) 
    at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:39) 
    at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:27) 
    at java.lang.reflect.Constructor.newInstance(Constructor.java:513) 

顯然屬性子對象不具有用戶對象集的ID。

我知道我可以做以下工作，但看起來很奇怪，我不能僅僅創建一個對象層次結構，並且Hibernate會計劃如何設置相應的ID。我懷疑這是沒有辦法的，因爲saveAndFlush（）返回一個新的實例，而不僅僅是更新輸入參數的版本。

User user = new User("joe1.bloggs@ft.com", "xyz"); 
    user.setScreenName("joe1bloggs"); 

    // target is an JpaRepository intergafe 
    user = target.saveAndFlush(user); 

    user.addAttribute("domain", "name", 212); 

    target.saveAndFlush(user); 

任何人有任何想法，或只是一個生活的情況嗎？

感謝

尼克

編輯：您可以得到這個通過添加@MapsId註釋子類（感謝axtavt的答覆）工作。即

@MapsId("userId") 
    @ManyToOne(fetch = FetchType.LAZY) 
    @JoinColumn(name = "userId", nullable = false, insertable = false, updatable = false) 
    private User user; 

Answer 1

您是否嘗試過如下圖吧：

@ManyToOne(fetch = FetchType.LAZY)  
@MapsId("userid") 
private User user; 

至於我在這種情況下userid的AttributePk領域的理解應與user的ID自動填充。