Hibernate：发现具有给定标识符的多行错误

Question

我正在使用spring 4.0.5和hibernate 4.3.5；我在hibernate中遇到了一个错误，我不知道我错在哪里（因为我确信我错了）。我有一个与自己相关的表，它代表一个web树，其中每个根节点可以有几个子节点，所以我创建了这个类：

@DynamicUpdate
@Cache(region = "it.eng.angelo.spring.dao.hibernate.models.WebTree", usage = CacheConcurrencyStrategy.READ_WRITE)
@Entity
@Table(name = "MEDIA_GALL_TREE", indexes = {@Index(name = "NOME_FOLDER_IDX", columnList = "NOME_FOLDER")})
public class WebTree extends AbstractModel
{

    private static final long serialVersionUID = -4572195412018767502L;
    private long id;
    private String text;
    private boolean opened;
    private boolean disabled;
    private boolean selected;
    private Set<WebTree> children = new HashSet<WebTree>(0);
    private Set<Media> media = new HashSet<Media>(0);
    private WebTree father;
    private WcmDomain dominio;
    public WebTree()
    {
        super();
    }
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    @Column(name = "ID_FOLDER", unique = true, nullable = false)
    public long getId()
    {
        return id;
    }
    public void setId(long id)
    {
        this.id = id;
    }
    @Column(name = "NOME_FOLDER", nullable = false, unique=false)
    public String getText()
    {
        return text;
    }
    public void setText(String text)
    {
        this.text = text;
    }
    @Column(name = "OPENED_FOLDER")
    public boolean isOpened()
    {
        return opened;
    }
    public void setOpened(boolean opened)
    {
        this.opened = opened;
    }
    @Column(name = "DISABLED_FOLDER")
    public boolean isDisabled()
    {
        return disabled;
    }
    public void setDisabled(boolean disabled)
    {
        this.disabled = disabled;
    }
    @Column(name = "SELECTED_FOLDER")
    public boolean isSelected()
    {
        return selected;
    }
    public void setSelected(boolean selected)
    {
        this.selected = selected;
    }
    @OneToMany(mappedBy = "father", orphanRemoval = true, targetEntity = WebTree.class)
    public Set<WebTree> getChildren()
    {
        return children;
    }
    public void setChildren(Set<WebTree> children)
    {
        this.children = children;
    }
    @ManyToOne(targetEntity = WebTree.class)
    @JoinColumn(name = "ID_PADRE", nullable = true)
    public WebTree getFather()
    {
        return father;
    }
    public void setFather(WebTree father)
    {
        this.father = father;
    }
    @OneToOne
    @JoinColumn(name="ID_DOMINIO", nullable=false)
    public WcmDomain getDominio()
    {
        return dominio;
    }
    public void setDominio(WcmDomain dominio)
    {
        this.dominio = dominio;
    }
    @OneToMany( mappedBy = "folder", orphanRemoval = true, targetEntity = Media.class, cascade = { CascadeType.ALL })
    public Set<Media> getMedia()
    {
        return media;
    }
    public void setMedia(Set<Media> media)
    {
        this.media = media;
    }

}

正如您所看到的...这是一个非常简单的POJO类；现在我创建了这个单元测试：

@Test
public void testLoadModifyTree()
{
    try
    {
        DetachedCriteria dc = DetachedCriteria.forClass(MediaGalleryTree.class);
        dc.setFetchMode("father", FetchMode.JOIN);
        dc.add(Property.forName("id").eq(4l));
        List<MediaGalleryTree> result = hibSvc.search(dc, IConstants.NO_PAGINATION, IConstants.NO_PAGINATION);
        for (MediaGalleryTree mediaGalleryTree : result)
        {
            logger.info(mediaGalleryTree.getId());
        }
    }
    catch (Exception e)
    {
        logger.error(e.getMessage(), e);
    }
}

嗯，我检查了一下，在DB中我只有一个ID为4的记录；当我执行这个查询时，我得到了以下错误：

18:48:43,123 ERROR [WcmHibernateDao] Errore nella ricerca con detached criteria DetachableCriteria(CriteriaImpl(it.eng.comi.spring.dao.hibernate.models.MediaGalleryTree:this[][id=4])); More than one row with the given identifier was found: 2, for class: it.eng.comi.spring.dao.hibernate.models.MediaGalleryTree
org.hibernate.HibernateException: More than one row with the given identifier was found: 2, for class: it.eng.comi.spring.dao.hibernate.models.MediaGalleryTree
    at org.hibernate.loader.entity.AbstractEntityLoader.load(AbstractEntityLoader.java:100)
    at org.hibernate.loader.entity.EntityLoader.loadByUniqueKey(EntityLoader.java:161)
    at org.hibernate.persister.entity.AbstractEntityPersister.loadByUniqueKey(AbstractEntityPersister.java:2385)
    at org.hibernate.type.EntityType.loadByUniqueKey(EntityType.java:767)
    at org.hibernate.type.EntityType.resolve(EntityType.java:505)
    at org.hibernate.engine.internal.TwoPhaseLoad.doInitializeEntity(TwoPhaseLoad.java:170)
    at org.hibernate.engine.internal.TwoPhaseLoad.initializeEntity(TwoPhaseLoad.java:144)
    at org.hibernate.loader.Loader.initializeEntitiesAndCollections(Loader.java:1114)
    at org.hibernate.loader.Loader.processResultSet(Loader.java:972)
    at org.hibernate.loader.Loader.doQuery(Loader.java:920)
    at org.hibernate.loader.Loader.doQueryAndInitializeNonLazyCollections(Loader.java:354)
    at org.hibernate.loader.Loader.doList(Loader.java:2553)
    at org.hibernate.loader.Loader.doList(Loader.java:2539)
    at org.hibernate.loader.Loader.listIgnoreQueryCache(Loader.java:2369)
    at org.hibernate.loader.Loader.list(Loader.java:2364)
    at org.hibernate.loader.criteria.CriteriaLoader.list(CriteriaLoader.java:126)
    at org.hibernate.internal.SessionImpl.list(SessionImpl.java:1682)
    at org.hibernate.internal.CriteriaImpl.list(CriteriaImpl.java:380)
    at it.eng.comi.spring.dao.WcmHibernateDao.searchEntity(WcmHibernateDao.java:140)
    at it.eng.comi.spring.service.impl.WcmRdbmsExtSvcImpl.search(WcmRdbmsExtSvcImpl.java:237)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:606)
    at org.springframework.aop.support.AopUtils.invokeJoinpointUsingReflection(AopUtils.java:317)
    at org.springframework.aop.framework.ReflectiveMethodInvocation.invokeJoinpoint(ReflectiveMethodInvocation.java:190)
    at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:157)
    at org.springframework.transaction.interceptor.TransactionInterceptor$1.proceedWithInvocation(TransactionInterceptor.java:98)
    at org.springframework.transaction.interceptor.TransactionAspectSupport.invokeWithinTransaction(TransactionAspectSupport.java:262)
    at org.springframework.transaction.interceptor.TransactionInterceptor.invoke(TransactionInterceptor.java:95)
    at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:179)
    at org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:207)
    at com.sun.proxy.$Proxy45.search(Unknown Source)
    at it.eng.comi.test.ComiTests.testLoadModifyTree(ComiTests.java:578)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:606)
    at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:47)
    at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12)
    at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:44)
    at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:17)
    at org.springframework.test.context.junit4.statements.RunBeforeTestMethodCallbacks.evaluate(RunBeforeTestMethodCallbacks.java:74)
    at org.springframework.test.context.junit4.statements.RunAfterTestMethodCallbacks.evaluate(RunAfterTestMethodCallbacks.java:83)
    at org.springframework.test.context.junit4.statements.SpringRepeat.evaluate(SpringRepeat.java:72)
    at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.runChild(SpringJUnit4ClassRunner.java:233)
    at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.runChild(SpringJUnit4ClassRunner.java:87)
    at org.junit.runners.ParentRunner$3.run(ParentRunner.java:238)
    at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:63)
    at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:236)
    at org.junit.runners.ParentRunner.access$000(ParentRunner.java:53)
    at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:229)
    at org.springframework.test.context.junit4.statements.RunBeforeTestClassCallbacks.evaluate(RunBeforeTestClassCallbacks.java:61)
    at org.springframework.test.context.junit4.statements.RunAfterTestClassCallbacks.evaluate(RunAfterTestClassCallbacks.java:71)
    at org.junit.runners.ParentRunner.run(ParentRunner.java:309)
    at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.run(SpringJUnit4ClassRunner.java:176)
    at org.eclipse.jdt.internal.junit4.runner.JUnit4TestReference.run(JUnit4TestReference.java:50)
    at org.eclipse.jdt.internal.junit.runner.TestExecution.run(TestExecution.java:38)
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:467)
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:683)
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run(RemoteTestRunner.java:390)
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:197)
18:48:43,135 ERROR [WcmRdbmsExtSvcImpl] Errore nella ricerca con deatchedCriteria DetachableCriteria(CriteriaImpl(it.eng.comi.spring.dao.hibernate.models.MediaGalleryTree:this[][id=4])); Errore nella ricerca con detached criteria DetachableCriteria(CriteriaImpl(it.eng.comi.spring.dao.hibernate.models.MediaGalleryTree:this[][id=4])); More than one row with the given identifier was found: 2, for class: it.eng.comi.spring.dao.hibernate.models.MediaGalleryTree
it.eng.comi.exception.CoMiDbException: Errore nella ricerca con detached criteria DetachableCriteria(CriteriaImpl(it.eng.comi.spring.dao.hibernate.models.MediaGalleryTree:this[][id=4])); More than one row with the given identifier was found: 2, for class: it.eng.comi.spring.dao.hibernate.models.MediaGalleryTree
    at it.eng.comi.spring.dao.WcmHibernateDao.searchEntity(WcmHibernateDao.java:146)
    at it.eng.comi.spring.service.impl.WcmRdbmsExtSvcImpl.search(WcmRdbmsExtSvcImpl.java:237)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:606)
    at org.springframework.aop.support.AopUtils.invokeJoinpointUsingReflection(AopUtils.java:317)
    at org.springframework.aop.framework.ReflectiveMethodInvocation.invokeJoinpoint(ReflectiveMethodInvocation.java:190)
    at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:157)
    at org.springframework.transaction.interceptor.TransactionInterceptor$1.proceedWithInvocation(TransactionInterceptor.java:98)
    at org.springframework.transaction.interceptor.TransactionAspectSupport.invokeWithinTransaction(TransactionAspectSupport.java:262)
    at org.springframework.transaction.interceptor.TransactionInterceptor.invoke(TransactionInterceptor.java:95)
    at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:179)
    at org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:207)
    at com.sun.proxy.$Proxy45.search(Unknown Source)
    at it.eng.comi.test.ComiTests.testLoadModifyTree(ComiTests.java:578)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:606)
    at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:47)
    at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12)
    at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:44)
    at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:17)
    at org.springframework.test.context.junit4.statements.RunBeforeTestMethodCallbacks.evaluate(RunBeforeTestMethodCallbacks.java:74)
    at org.springframework.test.context.junit4.statements.RunAfterTestMethodCallbacks.evaluate(RunAfterTestMethodCallbacks.java:83)
    at org.springframework.test.context.junit4.statements.SpringRepeat.evaluate(SpringRepeat.java:72)
    at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.runChild(SpringJUnit4ClassRunner.java:233)
    at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.runChild(SpringJUnit4ClassRunner.java:87)
    at org.junit.runners.ParentRunner$3.run(ParentRunner.java:238)
    at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:63)
    at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:236)
    at org.junit.runners.ParentRunner.access$000(ParentRunner.java:53)
    at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:229)
    at org.springframework.test.context.junit4.statements.RunBeforeTestClassCallbacks.evaluate(RunBeforeTestClassCallbacks.java:61)
    at org.springframework.test.context.junit4.statements.RunAfterTestClassCallbacks.evaluate(RunAfterTestClassCallbacks.java:71)
    at org.junit.runners.ParentRunner.run(ParentRunner.java:309)
    at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.run(SpringJUnit4ClassRunner.java:176)
    at org.eclipse.jdt.internal.junit4.runner.JUnit4TestReference.run(JUnit4TestReference.java:50)
    at org.eclipse.jdt.internal.junit.runner.TestExecution.run(TestExecution.java:38)
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:467)
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:683)
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run(RemoteTestRunner.java:390)
    at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:197)
Caused by: org.hibernate.HibernateException: More than one row with the given identifier was found: 2, for class: it.eng.comi.spring.dao.hibernate.models.MediaGalleryTree
    at org.hibernate.loader.entity.AbstractEntityLoader.load(AbstractEntityLoader.java:100)
    at org.hibernate.loader.entity.EntityLoader.loadByUniqueKey(EntityLoader.java:161)
    at org.hibernate.persister.entity.AbstractEntityPersister.loadByUniqueKey(AbstractEntityPersister.java:2385)
    at org.hibernate.type.EntityType.loadByUniqueKey(EntityType.java:767)
    at org.hibernate.type.EntityType.resolve(EntityType.java:505)
    at org.hibernate.engine.internal.TwoPhaseLoad.doInitializeEntity(TwoPhaseLoad.java:170)
    at org.hibernate.engine.internal.TwoPhaseLoad.initializeEntity(TwoPhaseLoad.java:144)
    at org.hibernate.loader.Loader.initializeEntitiesAndCollections(Loader.java:1114)
    at org.hibernate.loader.Loader.processResultSet(Loader.java:972)
    at org.hibernate.loader.Loader.doQuery(Loader.java:920)
    at org.hibernate.loader.Loader.doQueryAndInitializeNonLazyCollections(Loader.java:354)
    at org.hibernate.loader.Loader.doList(Loader.java:2553)
    at org.hibernate.loader.Loader.doList(Loader.java:2539)
    at org.hibernate.loader.Loader.listIgnoreQueryCache(Loader.java:2369)
    at org.hibernate.loader.Loader.list(Loader.java:2364)
    at org.hibernate.loader.criteria.CriteriaLoader.list(CriteriaLoader.java:126)
    at org.hibernate.internal.SessionImpl.list(SessionImpl.java:1682)
    at org.hibernate.internal.CriteriaImpl.list(CriteriaImpl.java:380)
    at it.eng.comi.spring.dao.WcmHibernateDao.searchEntity(WcmHibernateDao.java:140)
    ... 43 more

执行代码时，hibernate打印这些查询：

Hibernate: 
    select
        this_.ID_FOLDER as ID_FOLDE1_7_2_,
        this_.UT_INS as UT_INS2_7_2_,
        this_.DT_INS as DT_INS3_7_2_,
        this_.DT_UPD as DT_UPD4_7_2_,
        this_.UT_UPD as UT_UPD5_7_2_,
        this_.DISABLED_FOLDER as DISABLED6_7_2_,
        this_.ID_DOMINIO as ID_DOMI10_7_2_,
        this_.ID_PADRE as ID_PADR11_7_2_,
        this_.OPENED_FOLDER as OPENED_F7_7_2_,
        this_.SELECTED_FOLDER as SELECTED8_7_2_,
        this_.NOME_FOLDER as NOME_FOL9_7_2_,
        wcmdomain2_.ID_DOMINIO as ID_DOMIN1_8_0_,
        wcmdomain2_.UT_INS as UT_INS2_8_0_,
        wcmdomain2_.DT_INS as DT_INS3_8_0_,
        wcmdomain2_.DT_UPD as DT_UPD4_8_0_,
        wcmdomain2_.UT_UPD as UT_UPD5_8_0_,
        wcmdomain2_.WCM_NOME_DOMINIO as WCM_NOME6_8_0_,
        mediagalle3_.ID_FOLDER as ID_FOLDE1_7_1_,
        mediagalle3_.UT_INS as UT_INS2_7_1_,
        mediagalle3_.DT_INS as DT_INS3_7_1_,
        mediagalle3_.DT_UPD as DT_UPD4_7_1_,
        mediagalle3_.UT_UPD as UT_UPD5_7_1_,
        mediagalle3_.DISABLED_FOLDER as DISABLED6_7_1_,
        mediagalle3_.ID_DOMINIO as ID_DOMI10_7_1_,
        mediagalle3_.ID_PADRE as ID_PADR11_7_1_,
        mediagalle3_.OPENED_FOLDER as OPENED_F7_7_1_,
        mediagalle3_.SELECTED_FOLDER as SELECTED8_7_1_,
        mediagalle3_.NOME_FOLDER as NOME_FOL9_7_1_ 
    from
        MEDIA_GALL_TREE this_ 
    inner join
        WCM_DOMAIN wcmdomain2_ 
            on this_.ID_DOMINIO=wcmdomain2_.ID_DOMINIO 
    left outer join
        MEDIA_GALL_TREE mediagalle3_ 
            on this_.ID_PADRE=mediagalle3_.ID_FOLDER 
    where
        this_.ID_FOLDER=?
Hibernate: 
    select
        mediagalle0_.ID_FOLDER as ID_FOLDE1_7_2_,
        mediagalle0_.UT_INS as UT_INS2_7_2_,
        mediagalle0_.DT_INS as DT_INS3_7_2_,
        mediagalle0_.DT_UPD as DT_UPD4_7_2_,
        mediagalle0_.UT_UPD as UT_UPD5_7_2_,
        mediagalle0_.DISABLED_FOLDER as DISABLED6_7_2_,
        mediagalle0_.ID_DOMINIO as ID_DOMI10_7_2_,
        mediagalle0_.ID_PADRE as ID_PADR11_7_2_,
        mediagalle0_.OPENED_FOLDER as OPENED_F7_7_2_,
        mediagalle0_.SELECTED_FOLDER as SELECTED8_7_2_,
        mediagalle0_.NOME_FOLDER as NOME_FOL9_7_2_,
        wcmdomain1_.ID_DOMINIO as ID_DOMIN1_8_0_,
        wcmdomain1_.UT_INS as UT_INS2_8_0_,
        wcmdomain1_.DT_INS as DT_INS3_8_0_,
        wcmdomain1_.DT_UPD as DT_UPD4_8_0_,
        wcmdomain1_.UT_UPD as UT_UPD5_8_0_,
        wcmdomain1_.WCM_NOME_DOMINIO as WCM_NOME6_8_0_,
        mediagalle2_.ID_FOLDER as ID_FOLDE1_7_1_,
        mediagalle2_.UT_INS as UT_INS2_7_1_,
        mediagalle2_.DT_INS as DT_INS3_7_1_,
        mediagalle2_.DT_UPD as DT_UPD4_7_1_,
        mediagalle2_.UT_UPD as UT_UPD5_7_1_,
        mediagalle2_.DISABLED_FOLDER as DISABLED6_7_1_,
        mediagalle2_.ID_DOMINIO as ID_DOMI10_7_1_,
        mediagalle2_.ID_PADRE as ID_PADR11_7_1_,
        mediagalle2_.OPENED_FOLDER as OPENED_F7_7_1_,
        mediagalle2_.SELECTED_FOLDER as SELECTED8_7_1_,
        mediagalle2_.NOME_FOLDER as NOME_FOL9_7_1_ 
    from
        MEDIA_GALL_TREE mediagalle0_ 
    inner join
        WCM_DOMAIN wcmdomain1_ 
            on mediagalle0_.ID_DOMINIO=wcmdomain1_.ID_DOMINIO 
    left outer join
        MEDIA_GALL_TREE mediagalle2_ 
            on mediagalle0_.ID_PADRE=mediagalle2_.ID_FOLDER 
    where
        mediagalle0_.ID_DOMINIO=?

这些是我的表记录：

id_folder; ut_ins; dt_ins; dt_upd; ut_upd; disabled_folder; opened_folder; selected_folder; nome_folder; id_dominio; id_padre
"1";"system";"2014-06-12 18:23:16.649";"2014-06-12 18:23:16.649";"system";FALSE;FALSE;FALSE;"Root 1";1;
"2";"system";"2014-06-12 18:23:16.662";"2014-06-12 18:23:16.662";"system";FALSE;FALSE;FALSE;"Root 2";2;
"4";"wpsAdmin";"2014-06-13 16:18:01.428";"2014-06-13 18:12:14.228";"wpsAdmin";FALSE;FALSE;FALSE;"Testina";2;2
"7";"wpsAdmin";"2014-06-13 17:33:05.575";"2014-06-13 17:33:10.275";"wpsAdmin";FALSE;FALSE;FALSE;"Angelo";2;2

谁能告诉我我错在哪里吗？在我看来都是正确的...任何提示都是受欢迎的

谢谢你安吉洛

只需注意：如果我以这样的方式实现POJO类方法getChildern,那么所有的工作都很好：

@OneToMany( mappedBy = "father", targetEntity = WebTree.class, fetch=FetchType.EAGER)
public Set<WebTree> getChildren()
{
    return children;
}

但我想知道为什么会有这种行为？

谢谢你安吉洛

Answer 1

对不起；这是我的错误在我的实体类中，我错误地将一个关系映射为OneToOne；相反，它是oneToMany：）现在所有的工作都很好.....；这是我的新实体类：

@DynamicUpdate
@Cache(region = "it.eng.angelo.spring.dao.hibernate.models.MediaGalleryTree", usage = CacheConcurrencyStrategy.READ_WRITE)
@Entity
@Table(name = "MEDIA_GALL_TREE", indexes = {@Index(name = "NOME_FOLDER_IDX", columnList = "NOME_FOLDER")})
public class MediaGalleryTree extends AbstractModel
{

    private static final long serialVersionUID = -4572195412018767502L;
    private long id;
    private String text;
    private boolean opened;
    private boolean disabled;
    private boolean selected;
    private Set<MediaGalleryTree> children = new HashSet<MediaGalleryTree>(0);
    private Set<FedoraCommonsEntity> media = new HashSet<FedoraCommonsEntity>(0);
    private MediaGalleryTree father;
    private WcmDomain dominio;
    public MediaGalleryTree()
    {
        super();
    }
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    @Column(name = "ID_FOLDER", unique = true, nullable = false)
    public long getId()
    {
        return id;
    }
    public void setId(long id)
    {
        this.id = id;
    }
    @Column(name = "NOME_FOLDER", nullable = false, unique=false)
    public String getText()
    {
        return text;
    }
    public void setText(String text)
    {
        this.text = text;
    }
    @Column(name = "OPENED_FOLDER")
    public boolean isOpened()
    {
        return opened;
    }
    public void setOpened(boolean opened)
    {
        this.opened = opened;
    }
    @Column(name = "DISABLED_FOLDER")
    public boolean isDisabled()
    {
        return disabled;
    }
    public void setDisabled(boolean disabled)
    {
        this.disabled = disabled;
    }
    @Column(name = "SELECTED_FOLDER")
    public boolean isSelected()
    {
        return selected;
    }
    public void setSelected(boolean selected)
    {
        this.selected = selected;
    }
    @OneToMany( mappedBy = "father", orphanRemoval = true, 
                targetEntity = MediaGalleryTree.class)
    public Set<MediaGalleryTree> getChildren()
    {
        return children;
    }
    public void setChildren(Set<MediaGalleryTree> children)
    {
        this.children = children;
    }
    @ManyToOne(targetEntity = MediaGalleryTree.class)
    @JoinColumn(name = "ID_PADRE", nullable = true)
    public MediaGalleryTree getFather()
    {
        return father;
    }
    public void setFather(MediaGalleryTree father)
    {
        this.father = father;
    }
    @ManyToOne(targetEntity = WcmDomain.class, cascade={CascadeType.ALL})
    @JoinColumn(name="ID_DOMINIO", nullable=false)
    public WcmDomain getDominio()
    {
        return dominio;
    }
    public void setDominio(WcmDomain dominio)
    {
        this.dominio = dominio;
    }
    @OneToMany( mappedBy = "folder", orphanRemoval = true, 
            targetEntity = Media.class, cascade = { CascadeType.ALL })
    public Set<FedoraCommonsEntity> getMedia()
    {
        return media;
    }
    public void setMedia(Set<FedoraCommonsEntity> media)
    {
        this.media = media;
    }

}

安吉洛

Answer 2

我被org.hibernate.hibernateException给攻破了：找到了一个以上具有给定标识符的行:问题，并且没有找到有关StackOverflow的帮助。解决这个问题花了一段时间，所以我在这里记录了解决方案。我使用的是JPA/Hibernate和spring数据。

首先，这不是由数据库中的重复行引起的，因为显然不可能有重复的主键。相反，这是由Hibernate查找对象并急切地用左外部连接填充一对一关系引起的。Hibernate假设会返回单行，但返回了两行，因为有两个对象与一对一关系相关联。

下面是我的对象的简化版本：

@Entity
@Table(name = "plate")
public class Plate {
    private static final long serialVersionUID = 1L;

    @Id
    @SequenceGenerator(name="test_seq", sequenceName="test_seq")
    @GeneratedValue(strategy = GenerationType.SEQUENCE, generator = "test_seq")
    @Column(name = "id")
    private Long id;

    @Version
    @Column(name = "object_version")
    private long objectVersion;

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

    @OneToOne(mappedBy = "plate")
    private Sheet sheet;

    public Sheet getSheet() {
        return sheet;
    }

    public void setSheet(Sheet sheet) {
        if (this.sheet != null) {
            this.sheet.setPlate(null);
        }

        this.sheet = sheet;
        sheet.setPlate(this);
    }
}


@Entity
@Table(name = "sheet")
public class Sheet {
    private static final long serialVersionUID = 1L;

    @Id
    @SequenceGenerator(name="test_seq", sequenceName="test_seq")
    @GeneratedValue(strategy = GenerationType.SEQUENCE, generator = "test_seq")
    @Column(name = "id")
    private Long id;

    @Version
    @Column(name = "object_version")
    private long objectVersion;

    @Column(name = "sheet_name")
    private String sheetName;

    @OneToOne
    @JoinColumn(name = "plate_id")
    private Plate plate;

    public Plate getPlate() {
        return plate;
    }

    // Do not use. Use Plate.setSheet() instead
    void setPlate(Plate plate) {
        this.plate = plate;
    }
}

问题是板和薄板之间的“单一”关系。我最初不想删除孤儿表。在我的代码中，我按id查找了一个板，并添加了一个新的表单。这将板到板的关系从原始板上移除。提交事务时，我假设JPA会保存所有修改过的对象(Plate、原始工作表和新工作表）。

这不是真的！JPA显然是通过从最初加载的对象（Plate）向下遍历层次结构来找到修改过的对象，而它忽略了原来的工作表（现在是孤立的）被修改过的事实。这意味着原始工作表的sheet.plate_id列在数据库中未被清除。换句话说，我打破了它们在数据模型中的关系，但它未能保存到数据库。因此，下一次我尝试加载板时，Hibernate运行如下所示的查询：

select
    plate1_.id as id1_19_12_, 
    plate1_.object_version as object_v2_19_12_, 
    plate1_.name as name3_19_12_, 
    sheet2_.id as id1_39_12_, 
    sheet2_.object_version as object_v2_39_12_, 
    sheet2_.sheet_name as sheet_nam2_39_12_, 
    sheet2_.plate_id as plate_id4_39_12_, 
from 
    plate plate1_
    left outer join sheet sheet2_ on plate1_.id = sheet2_.plate_id
where 
    plate1_.id=?

这将在结果集中返回2行,并产生以下错误：

org.hibernate.HibernateException: More than one row with the given identifier was found: 10045, for class: com.example.Plate

这是有欺骗性的：数据库中只有一个带有该id的Plate行，但却有两个工作表链接到它。

解决方案：似乎我有两个选择：或者在一对一关系上级联all并删除Olphan，或者在每次删除原始工作表与plate的关系时显式调用我的repository类来查找并保存原始工作表。我选择了第一个选项,并将其添加到plate类中：

@OneToOne(mappedBy = "plate", cascade = CascadeType.ALL, orphanRemoval = true)
private Sheet sheet;

这样就解决了这个问题。