TransientObjectException - 对象引用未保存的瞬态实例 - 在刷新之前保存瞬态实例

Posted 2023-02-26

【中文标题】TransientObjectException - 对象引用未保存的瞬态实例 - 在刷新之前保存瞬态实例

【英文标题】：TransientObjectException - object references an unsaved transient instance - save the transient instance before flushing

【发布时间】：2012-11-08 19:21:28

【问题描述】：

对于我的问题，我已经找到了一些很好的答案，但这是关于从 Hibernate 3.4.0GA 升级到 Hibernate 4.1.8。所以这曾经在以前的版本下工作，我已经搜索了高低，为什么它会在这个新版本中中断。

我得到一个

org.hibernate.TransientObjectException：对象引用了一个未保存的瞬态实例 - 在刷新之前保存瞬态实例：com.test.server.domain.model.NoteItem.note -> com.test.server.domain.model.Note

任何帮助都会很棒。

这是我的课程。

@MappedSuperclass
public abstract class EntityBase implements Serializable 

    private static final long serialVersionUID = 1L;

    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    @Column(name = "ID")
    protected Long id;

    @Version
    @Column(name = "VERSION")
    protected Long version; 

    public Long getId() 
        return id;
    

    public Long getVersion() 
        return version;
    

    protected static final EntityManager entityManager() 
        return EntityManagerUtil.getEntityManager();
    


@Entity
@Table(name = "WORK_BOOK")
public class WorkBook extends EntityBase 
    private static final long serialVersionUID = 1L;

    @OneToOne(cascade = CascadeType.ALL)
    @JoinColumn(name = "NOTE_ID")
    private Note note;

    public WorkBook() 
        super();
    

    public Note getNote() 
        return note;
    

    public void setNote(Note note) 
        this.note = note;
    

    public WorkBook persist() 
        EntityManager em = entityManager();
        EntityTransaction tx = em.getTransaction();

        if (tx.isActive()) 
            return em.merge(this);
         else 
            tx.begin();
            WorkBook saved = em.merge(this);
            tx.commit();
            return saved;
        
    


@Entity
@Table(name = "NOTE")
public class Note extends EntityBase 
    private static final long serialVersionUID = 1L;

    @OneToOne(mappedBy = "note")
    private WorkBook workBook;

    @OneToMany(cascade = CascadeType.ALL, fetch = FetchType.LAZY, mappedBy = "note")
    private List<NoteItem> notes = new ArrayList<NoteItem>();

    public WorkBook getWorkBook() 
        return workBook;
    

    public List<NoteItem> getNotes() 
        return notes;
    

    public void setWorkBook(WorkBook workBook) 
        this.workBook = workBook;
    

    public void setNotes(List<NoteItem> notes) 
        if (notes != null) 
            for (NoteItem ni : notes) 
                ni.setNote(this);               
            
        

        this.notes = notes;
    
   

@Entity
@Table(name = "NOTE_ITEM")
public class NoteItem extends EntityBase 
    private static final long serialVersionUID = 1L;

    @Column(name = "NOTE_NAME")
    private String noteName;

    @Column(name = "NOTE_TEXT")
    private String noteText;

    @Column(name = "NOTE_DATE")
    private Date noteDate;

    @Column(name = "NOTE_CREATOR")
    private String noteCreator;

    @Column(name = "NOTE_CREATOR_ID")
    private Integer noteCreatorId;

    @ManyToOne
    @JoinColumn(name = "NOTE_ID", updatable = true)
    private Note note;

    public String getNoteName() 
        return noteName;
    

    public void setNoteName(String noteName) 
        this.noteName = noteName;
    

    public String getNoteText() 
        return noteText;
    

    public void setNoteText(String noteText) 
        this.noteText = noteText;
    

    public Date getNoteDate() 
        return noteDate;
    

    public void setNoteDate(Date noteDate) 
        this.noteDate = noteDate;
    

    public String getNoteCreator() 
        return noteCreator;
    

    public void setNoteCreator(String noteCreator) 
        this.noteCreator = noteCreator;
    

    public Integer getNoteCreatorId() 
        return noteCreatorId;
    

    public void setNoteCreatorId(Integer noteCreatorId) 
        this.noteCreatorId = noteCreatorId;
    

    public Note getNote() 
        return note;
    

    public void setNote(Note note) 
        this.note = note;
    

    public NoteItem create() 
        return new NoteItem();
    
   

【问题讨论】：

object references an unsaved transient instance - save the transient instance before flushing的可能重复

【参考方案1】：

在引入乐观锁定 (@Version) 后，我在所有 PUT HTTP 事务中都面临同样的错误

在更新实体时，必须发送该实体的 ID 和版本。 如果任何实体字段与其他实体相关，那么对于该字段，我们还应该提供 id 和版本值，而不是 JPA 尝试首先保留该相关实体

示例：我们有两个实体 --> Vehicle(id,Car,version) ; 汽车（id、版本、品牌） 更新/保留车辆实体确保车辆实体中的 Car 字段提供了 id 和 version 字段

【参考方案2】：

NoteItem 引用了之前必须保存的Note 的瞬态（尚未保存）实例。因此，请在属性注释上指定“Cascade.all”或先在注释上调用 saveorupdate。

【讨论】：

我没听懂，有没有可用的教程或者你可以进一步解释。 Note 是如何瞬态的？

NoteItem noteItem = ; noteItem.Note = new Note(); session.Save(noteItem);