JPA與具有@Inheritance（strategy = InheritanceType.JOINED）的實體的一對多關聯

Question

哈

我正在嘗試將一對多關聯映射到使用@Inheritance(strategy=InheritanceType.JOINED)映射的實體

....
@ManyToMany
@JoinTable(name = "S_MC_CC_CONTRATTIRAPPORTI",
    joinColumns = @JoinColumn(name = "COD_MULTICHANNELID"),
    inverseJoinColumns = @JoinColumn(name = "COD_RAPPORTO")
)   
private Collection<Rapporto> rapporti;
...

@Entity
@Table(name = "S_MC_CC_RAPPORTI")
@Inheritance(strategy=InheritanceType.JOINED)
@DiscriminatorColumn(name="COD_TIPORAPPORTO")
public abstract class Rapporto implements Serializable {

問題是我收到此異常異常描述：類型為[class java.lang.String]的指標字段值[1]的缺少類。

我認為JPA嘗試為該類標識一個DiscriminatorValue。 我想加載所有擴展超類的對象。

可能嗎？

詳細信息：這是協會的所有者

@Entity  
@Table(name = "S_MC_CC_CONTRATTI")
public class Contratto implements Serializable {

    @Id
    @Column(name = "COD_MULTICHANNELID")
    private String multichannelId;

    @ManyToMany()
    @JoinTable(name = "S_MC_CC_CONTRATTIRAPPORTI", joinColumns = @JoinColumn(name = "COD_MULTICHANNELID"), inverseJoinColumns = @JoinColumn(name = "COD_RAPPORTO")) 
    private Collection<Rapporto> rapporti;

這是多對多關聯的抽象類

@Entity
@Table(name = "S_MC_CC_RAPPORTI")
@Inheritance(strategy=InheritanceType.JOINED)
@DiscriminatorColumn(name="COD_TIPORAPPORTO")
public abstract class Rapporto implements Serializable {

    private static final long serialVersionUID = -5567166522882040440L;

    @Id
    @Column(name = "COD_RAPPORTO")  
    protected Long codiceRapporto;

這是兩個子類：

@Entity
@Table(name="S_MC_CC_CCCLIENTI")
@DiscriminatorValue("1 ")
public class ContoCorrente extends Rapporto {
    private static final long serialVersionUID = -3380622649760983262L;

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

@Entity
@Table(name = "S_MC_CC_RAPPORTI")
@DiscriminatorValue("6 ")
public class NumeroPortafoglioEstero extends Rapporto {

    private static final long serialVersionUID = 6869743707936663970L;

    /**
     * @param filiale
     * @param categoria
     * @param conto
     */
    public NumeroPortafoglioEstero(Filiale filiale, String categoria, String conto) {
        super(filiale, categoria, conto);
    }

這是例外：

Local Exception Stack: 
Exception [EclipseLink-43] (Eclipse Persistence Services - 2.1.2.v20101206-r8635): org.eclipse.persistence.exceptions.DescriptorException
Exception Description: Missing class for indicator field value [1] of type [class java.lang.String].
Descriptor: RelationalDescriptor(it.alten.intesasanpaolo.contratto.domain.core.rapporto.Rapporto --> [DatabaseTable(S_MC_CC_RAPPORTI)])
    at org.eclipse.persistence.exceptions.DescriptorException.missingClassForIndicatorFieldValue(DescriptorException.java:921)
    at org.eclipse.persistence.descriptors.InheritancePolicy.classFromValue(InheritancePolicy.java:355)
    at org.eclipse.persistence.descriptors.InheritancePolicy.classFromRow(InheritancePolicy.java:342)
    at org.eclipse.persistence.descriptors.InheritancePolicy.selectAllRowUsingDefaultMultipleTableSubclassRead(InheritancePolicy.java:1303)
    at org.eclipse.persistence.descriptors.InheritancePolicy.selectAllRowUsingMultipleTableSubclassRead(InheritancePolicy.java:1402)
    at org.eclipse.persistence.internal.queries.ExpressionQueryMechanism.selectAllRows(ExpressionQueryMechanism.java:2493)
    at org.eclipse.persistence.queries.ReadAllQuery.executeObjectLevelReadQuery(ReadAllQuery.java:407)
    at org.eclipse.persistence.queries.ObjectLevelReadQuery.executeDatabaseQuery(ObjectLevelReadQuery.java:1076)
    at org.eclipse.persistence.queries.DatabaseQuery.execute(DatabaseQuery.java:740)
    at org.eclipse.persistence.queries.ObjectLevelReadQuery.execute(ObjectLevelReadQuery.java:1036)
    at org.eclipse.persistence.queries.ReadAllQuery.execute(ReadAllQuery.java:380)
    at org.eclipse.persistence.internal.sessions.AbstractSession.internalExecuteQuery(AbstractSession.java:2392)
    at org.eclipse.persistence.internal.sessions.AbstractSession.executeQuery(AbstractSession.java:1291)
    at org.eclipse.persistence.internal.sessions.AbstractSession.executeQuery(AbstractSession.java:1273)
    at org.eclipse.persistence.internal.indirection.QueryBasedValueHolder.instantiate(QueryBasedValueHolder.java:96)
    at org.eclipse.persistence.internal.indirection.QueryBasedValueHolder.instantiate(QueryBasedValueHolder.java:86)
    at org.eclipse.persistence.internal.indirection.DatabaseValueHolder.getValue(DatabaseValueHolder.java:83)
    at org.eclipse.persistence.internal.indirection.UnitOfWorkValueHolder.instantiateImpl(UnitOfWorkValueHolder.java:160)
    at org.eclipse.persistence.internal.indirection.UnitOfWorkValueHolder.instantiate(UnitOfWorkValueHolder.java:220)
    at org.eclipse.persistence.internal.indirection.DatabaseValueHolder.getValue(DatabaseValueHolder.java:83)
    at org.eclipse.persistence.indirection.IndirectList.buildDelegate(IndirectList.java:237)
    at org.eclipse.persistence.indirection.IndirectList.getDelegate(IndirectList.java:398)
    at org.eclipse.persistence.indirection.IndirectList.toArray(IndirectList.java:741)
    at it.alten.intesasanpaolo.contratto.domain.core.anagrafica.Contratto.toString(Contratto.java:262)
    at java.lang.String.valueOf(String.java:2827)
    at java.io.PrintStream.println(PrintStream.java:771)
    at it.alten.intesasanpaolo.contratto.dao.core.anagrafica.TestContrattoDaoJpaImpl.testGetItemByID(TestContrattoDaoJpaImpl.java:99)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
    at java.lang.reflect.Method.invoke(Method.java:597)
    at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:44)
    at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:15)
    at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:41)
    at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:20)
    at org.junit.internal.runners.statements.RunBefores.evaluate(RunBefores.java:28)
    at org.junit.runners.BlockJUnit4ClassRunner.runNotIgnored(BlockJUnit4ClassRunner.java:79)
    at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:71)
    at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:49)
    at org.junit.runners.ParentRunner$3.run(ParentRunner.java:193)
    at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:52)
    at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:191)
    at org.junit.runners.ParentRunner.access$000(ParentRunner.java:42)
    at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:184)
    at org.junit.runners.ParentRunner.run(ParentRunner.java:236)
    at org.eclipse.jdt.internal.junit4.runner.JUnit4TestReference.run(JUnit4TestReference.java:49)
    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)

親切的問候Massimo

Answer 1

繼承層次結構中的每個實體都必須是一個用@Entity注釋並且具有@DiscriminatorValue

Answer 2

根據EclipseLink文檔（ 請參閱參考資料），當在繼承層次結構中找不到具有特定標識符值的類時，將發生此異常。

請注意，錯誤消息將鑒別符值顯示為1 ，而在@DiscriminatorValue中將其指定為"1 " 。 我認為這個多余的空間會引起問題-從數據庫中加載值時該空間會被剝離，或者數據庫中的舊值具有不帶空格的區分符。

Answer 3

我對@DiscriminatorValue進行了更改：現在超類定義了： @DiscriminatorColumn(name="COD_TIPORAPPORTO", discriminatorType=DiscriminatorType.STRING, length=2)
和親戚子類：
@DiscriminatorValue("1") 。
現在，我不再收到任何異常，但是為獲取數據而生成的查詢無法正常工作：這是生成的示例：

[EL Fine]: 2011-01-14 19:29:53.312--ServerSession(5230193)--Connection(5612344)--Thread(Thread[main,5,main])--SELECT t0.COD_RAPPORTO, t0.COD_TIPORAPPORTO, t0.COD_MATRICOLAGESTORE, t0.FLAG_RENDICONTAZIONE, t0.COD_CATEGORIA, t0.COD_STATORAPPORTO, t0.FLAG_SB_ATTIVO, t0.COD_GESTORE, t0.TIMESTAMP_AGGIORNAMENTO, t0.DESC_ATTRIBUTO, t0.NUM_RAPPORTO, t0.COD_NSG, t0.COD_ABI, t0.DEN_FILIALE, t1.COD_RAPPORTO, t1.COD_CIN, t1.DESC_DIVISA, t1.COD_CAB, t1.COD_IBAN, t1.COD_CHD, t1.COD_NAZIONE, t1.COD_SERVIZIO FROM S_MC_CC_RAPPORTI t0, S_MC_CC_CONTRATTIRAPPORTI t2, S_MC_CC_CCCLIENTI t1 WHERE (((t2.COD_MULTICHANNELID = ?) AND (t0.COD_RAPPORTO = t2.COD_RAPPORTO)) AND ((t1.COD_RAPPORTO = t0.COD_RAPPORTO) AND (t0.COD_TIPORAPPORTO = ?)))

綁定=> [01025640171576493，1]

實際上，通過Toad發布的查詢工作正常。 似乎加載所有數據的查詢正在運行，但實際上我看不到關聯的值。

誠摯的問候...