TransientObjectException：对象引用了一个未保存的临时实例-在执行合并时在刷新之前保存该临时实例

Question

谁能解释我为什么在合并时会出现TransientObjectException。 仅当我在ActivityTestEntity的构造函数中创建RuleTestEntitiy时，问题才重现，如下所示。 如果我进行更新或创建，它不会出现。

提前致谢。

这是一个测试：

 @ContextConfiguration(locations = { "classpath:testApplicationContext_db.xml"}) public class TransientObjectExceptionTest extends AbstractTestNGSpringContextTests{ @Autowired SessionFactory sessionFactory; @Test public void testAddTestActivity(){ Session session = sessionFactory.openSession(); Transaction tx1 = session.beginTransaction(); ActivityTestEntity newActivityEntity = new ActivityTestEntity(); session.merge(newActivityEntity); tx1.commit(); session.close(); sessionFactory.close(); } } 

@ContextConfiguration(locations = { "classpath:testApplicationContext_db.xml"}) public class TransientObjectExceptionTest extends AbstractTestNGSpringContextTests{ @Autowired SessionFactory sessionFactory; @Test public void testAddTestActivity(){ Session session = sessionFactory.openSession(); Transaction tx1 = session.beginTransaction(); ActivityTestEntity newActivityEntity = new ActivityTestEntity(); session.merge(newActivityEntity); tx1.commit(); session.close(); sessionFactory.close(); } }

异常：org.hibernate.TransientObjectException：对象引用了一个未保存的瞬态实例-在刷新之前保存该瞬态实例：com.xxx.RuleTestEntity

 @Entity @Table(name = "ACTIVITY_TEST") public class ActivityTestEntity implements Serializable{ private static final long serialVersionUID = 4190826330152288861L; @Id @GeneratedValue(strategy = GenerationType.AUTO) @Column(name = "ACTIVITY_ID", nullable = false) private long id; @OneToMany(mappedBy = "activity", cascade = CascadeType.ALL, fetch = FetchType.EAGER, orphanRemoval = true) private Set<RuleTestEntity> rules = new HashSet<>(); public ActivityTestEntity() { RuleTestEntity rule = new RuleTestEntity(); rule.setActivity(this); this.getRules().add(rule); } public long getId() { return id; } public void setId(long id) { this.id = id; } public Set<RuleTestEntity> getRules() { return rules; } public void setRules(Set<RuleTestEntity> rules) { this.rules = rules; } } 

@Entity @Table(name = "ACTIVITY_TEST") public class ActivityTestEntity implements Serializable{ private static final long serialVersionUID = 4190826330152288861L; @Id @GeneratedValue(strategy = GenerationType.AUTO) @Column(name = "ACTIVITY_ID", nullable = false) private long id; @OneToMany(mappedBy = "activity", cascade = CascadeType.ALL, fetch = FetchType.EAGER, orphanRemoval = true) private Set<RuleTestEntity> rules = new HashSet<>(); public ActivityTestEntity() { RuleTestEntity rule = new RuleTestEntity(); rule.setActivity(this); this.getRules().add(rule); } public long getId() { return id; } public void setId(long id) { this.id = id; } public Set<RuleTestEntity> getRules() { return rules; } public void setRules(Set<RuleTestEntity> rules) { this.rules = rules; } }

 @Entity @Table(name = "RULE_TEST") public class RuleTestEntity implements Serializable { private static final long serialVersionUID = -4208222848601642508L; @Id @GeneratedValue(strategy = GenerationType.AUTO) @Column(name = "RULE_ID", nullable = false) @XmlElement(name = Identifiable.ID_FIELD_NAME) private long id; @ManyToOne @JoinColumn(name = "ACTIVITY_ID", nullable = true, updatable = false) @XmlTransient private ActivityTestEntity activity; public ActivityTestEntity getActivity() { return activity; } public void setActivity(ActivityTestEntity activity) { this.activity = activity; } public long getId() { return id; } public void setId(long id) { this.id = id; } @Override public boolean equals(Object o) { if (this == o) { return true; } if (o == null || getClass() != o.getClass()) { return false; } RuleTestEntity that = (RuleTestEntity) o; if (id != that.id) { return false; } return activity != null ? activity.equals(that.activity) : that.activity == null; } @Override public int hashCode() { int result = (int) (id ^ (id >>> 32)); result = 31 * result + (activity != null ? activity.hashCode() : 0); return result; } } 

@Entity @Table(name = "RULE_TEST") public class RuleTestEntity implements Serializable { private static final long serialVersionUID = -4208222848601642508L; @Id @GeneratedValue(strategy = GenerationType.AUTO) @Column(name = "RULE_ID", nullable = false) @XmlElement(name = Identifiable.ID_FIELD_NAME) private long id; @ManyToOne @JoinColumn(name = "ACTIVITY_ID", nullable = true, updatable = false) @XmlTransient private ActivityTestEntity activity; public ActivityTestEntity getActivity() { return activity; } public void setActivity(ActivityTestEntity activity) { this.activity = activity; } public long getId() { return id; } public void setId(long id) { this.id = id; } @Override public boolean equals(Object o) { if (this == o) { return true; } if (o == null || getClass() != o.getClass()) { return false; } RuleTestEntity that = (RuleTestEntity) o; if (id != that.id) { return false; } return activity != null ? activity.equals(that.activity) : that.activity == null; } @Override public int hashCode() { int result = (int) (id ^ (id >>> 32)); result = 31 * result + (activity != null ? activity.hashCode() : 0); return result; } }

Answer 1

当您尝试保存引用未保存实体的实体时，将生成此异常。 您可以先保存引用的实体，然后再保存实体，或者可以在它们之间的关系中添加cascade=CascadeType.All 。

删除构造函数中的代码，然后尝试以下代码：

    Session session = sessionFactory.openSession();
    Transaction tx1 = session.beginTransaction();
    RuleTestEntity rule = new RuleTestEntity();
    session.save(rule);
    session.refresh(rule);
    ActivityTestEntity newActivityEntity = new ActivityTestEntity();
    Set<RuleTestEntity> rules = new HashSet<>();
    rules.add(rule);
    session.merge(newActivityEntity);
    tx1.commit();
    session.close();
    sessionFactory.close();