Question

我遇到了一些很好的问题答案，但这是关于从Hibernate 3.4.0GA升级到Hibernate 4.1.8的问题。所以这曾经在以前的版本下工作，我已经搜索了为什么它在这个新版本中突破的原因。

我得到了

org.hibernate.TransientObjectException：object引用未保存的瞬态实例 - 在刷新之前保存瞬态实例：com.test.server.domain.model.NoteItem.note - ＆gt; 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();
    }
}

Answer 1

NoteItem引用了之前必须保存的Note的瞬态（尚未保存）实例。因此，请在属性说明中指定“Cascade.all”，或者先在Note上调用saveorupdate。

Answer 2

在引入乐观锁定（@Version）后，所有PUT HTTP事务都面临相同的错误

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，那么我们也应该为该字段提供id和版本值，否则JPA会先尝试保留该相关实体

示例：我们有两个实体-> 车辆（id，汽车，版本）；汽车（ID，版本，品牌）要更新/保留车辆实体，请确保车辆实体中的汽车字段提供了ID和版本字段

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

2 个答案: