java - JPA 生成重复键

Question

我有两个实体定义为:

@Entity
public class FileMaster implements java.io.Serializable{

@Id
@GeneratedValue(strategy = GenerationType.IDENTITY)
private Long fileId;

@NotNull
@Column(unique = true)
private String fileNumber = "";
private String subject = "";

@Temporal(TemporalType.DATE)
private Date date=null;
private String authPerson="";
private String authDesign="";
private String department="";


@OneToMany(mappedBy = "fileMaster", cascade = CascadeType.ALL, orphanRemoval = true)
@JoinColumn(name="id") 
private Set<FileDetail> fileDetail = new HashSet<FileDetail>();

和第二个实体:

@Entity
public class FileDetail implements java.io.Serializable{
@Id
@GeneratedValue(strategy = GenerationType.AUTO)
private Long pdfId;

//@NotNull
@Column(unique = true)
private String name;

//@NotNull
@ManyToOne 
private FileMaster fileMaster;

下面的代码简单地尝试保留两个主从表。首先插入顺利并提交记录:

Set<FileDetail> pdfFileNames = newUpload.getPdfFileNames();
EntityManager em = Persistence.createEntityManagerFactory("fms")                
                        .createEntityManager();
em.getTransaction().begin();
FileMaster fileMaster = new FileMaster();

fileMaster.setFileNumber((String) editorForm.getField("fileNumber").getValue());
fileMaster.setSubject((String) editorForm.getField("subject").getValue());
fileMaster.setAuthDesign((String) 
editorForm.getField("authDesign").getValue());
fileMaster.setAuthPerson((String) editorForm.getField("authPerson").getValue());
fileMaster.setDate((Date) editorForm.getField("date").getValue());
fileMaster.setFileDetail(pdfFileNames);
em.persist(fileMaster);

Iterator<FileDetail> iter = pdfFileNames.iterator();

while(iter.hasNext()) {
    FileDetail fileDetail = iter.next();        
    fileDetail.setName(fileDetail.getName());
    fileDetail.setFileMaster(fileMaster);
    em.persist(fileDetail);     
    }           
em.getTransaction().commit();    
em.close();

当我尝试插入第二条记录时……它给了我 PSQLException。由于我是 JPA 的新手...顺便说一句，我正在使用 Eclipselink 和 PostgreSQL 以及 JPA...我发现很难解决这个问题。谁能帮我解决这个问题...让我也粘贴痕迹...

 May 27, 2012 10:08:02 AM com.vaadin.Application terminalError
 SEVERE: Terminal error:
 com.vaadin.event.ListenerMethod$MethodException
 Cause: javax.persistence.RollbackException: Exception [EclipseLink-4002] (Eclipse                          Services - 2.2.0.v20110202-r8913):      org.eclipse.persistence.exceptions.DatabaseException
Internal Exception: org.postgresql.util.PSQLException: ERROR: duplicate key value     violates unique constraint "filedetail_pkey"
Detail: Key (pdfid)=(306) already exists.
Error Code: 0
Call: INSERT INTO FILEDETAIL (PDFID, NAME, FILEMASTER_FILEID) VALUES (?, ?, ?)
bind => [306, Manning Java Persistence with Hibernate 2nd.pdf, 3]
Query: InsertObjectQuery(Manning Java Persistence with Hibernate 2nd.pdf)
at com.vaadin.event.ListenerMethod.receiveEvent(ListenerMethod.java:532)
at com.vaadin.event.EventRouter.fireEvent(EventRouter.java:164)
at com.vaadin.ui.AbstractComponent.fireEvent(AbstractComponent.java:1219)
at com.vaadin.ui.Button.fireClick(Button.java:550)
at com.vaadin.ui.Button.changeVariables(Button.java:217)
at com.vaadin.terminal.gwt.server.AbstractCommunicationManager.changeVariables(AbstractCommunicationManager.java:1451)
at com.vaadin.terminal.gwt.server.AbstractCommunicationManager.handleVariableBurst(AbstractCommunicationManager.java:1399)
at com.vaadin.terminal.gwt.server.AbstractCommunicationManager.handleVariables(AbstractCommunicationManager.java:1318)
at com.vaadin.terminal.gwt.server.AbstractCommunicationManager.doHandleUidlRequest(AbstractCommunicationManager.java:763)
at com.vaadin.terminal.gwt.server.CommunicationManager.handleUidlRequest(CommunicationManager.java:296)
at com.vaadin.terminal.gwt.server.AbstractApplicationServlet.service(AbstractApplicationServlet.java:501)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:848)
at org.eclipse.jetty.servlet.ServletHolder.handle(ServletHolder.java:598)
at org.eclipse.jetty.servlet.ServletHandler.doHandle(ServletHandler.java:486)
at org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:119)
at org.eclipse.jetty.security.SecurityHandler.handle(SecurityHandler.java:524)
at org.eclipse.jetty.server.session.SessionHandler.doHandle(SessionHandler.java:233)
at org.eclipse.jetty.server.handler.ContextHandler.doHandle(ContextHandler.java:1065)
at org.eclipse.jetty.servlet.ServletHandler.doScope(ServletHandler.java:413)
at org.eclipse.jetty.server.session.SessionHandler.doScope(SessionHandler.java:192)
at org.eclipse.jetty.server.handler.ContextHandler.doScope(ContextHandler.java:999)
at org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:117)
at org.eclipse.jetty.server.handler.ContextHandlerCollection.handle(ContextHandlerCollection.java:250)
at org.eclipse.jetty.server.handler.HandlerCollection.handle(HandlerCollection.java:149)
at org.eclipse.jetty.server.handler.HandlerWrapper.handle(HandlerWrapper.java:111)
at org.eclipse.jetty.server.Server.handle(Server.java:350)
at org.eclipse.jetty.server.AbstractHttpConnection.handleRequest(AbstractHttpConnection.java:454)
at org.eclipse.jetty.server.AbstractHttpConnection.content(AbstractHttpConnection.java:900)
at org.eclipse.jetty.server.AbstractHttpConnection$RequestHandler.content(AbstractHttpConnection.java:954)
at org.eclipse.jetty.http.HttpParser.parseNext(HttpParser.java:851)
at org.eclipse.jetty.http.HttpParser.parseAvailable(HttpParser.java:235)
at org.eclipse.jetty.server.AsyncHttpConnection.handle(AsyncHttpConnection.java:77)
at org.eclipse.jetty.io.nio.SelectChannelEndPoint.handle(SelectChannelEndPoint.java:606)
at org.eclipse.jetty.io.nio.SelectChannelEndPoint$1.run(SelectChannelEndPoint.java:46)
at org.eclipse.jetty.util.thread.QueuedThreadPool.runJob(QueuedThreadPool.java:603)
at org.eclipse.jetty.util.thread.QueuedThreadPool$3.run(QueuedThreadPool.java:538)
at java.lang.Thread.run(Unknown Source)
Caused by: javax.persistence.RollbackException: Exception [EclipseLink-4002] (Eclipse        Persistence Services - 2.2.0.v20110202-r8913):    org.eclipse.persistence.exceptions.DatabaseException
Internal Exception: org.postgresql.util.PSQLException: ERROR: duplicate key value  violates unique constraint "filedetail_pkey"
Detail: Key (pdfid)=(306) already exists.
Error Code: 0
Call: INSERT INTO FILEDETAIL (PDFID, NAME, FILEMASTER_FILEID) VALUES (?, ?, ?)
bind => [306, Manning Java Persistence with Hibernate 2nd.pdf, 3]
Query: InsertObjectQuery(Manning Java Persistence with Hibernate 2nd.pdf)
at    org.eclipse.persistence.internal.jpa.transaction.EntityTransactionImpl.commitInternal(Entit yTransactionImpl.java:102)
at  org.eclipse.persistence.internal.jpa.transaction.EntityTransactionImpl.commit(EntityTransac tionImpl.java:63)
at com.complete.raspberry.webui.PersonEditor.save(PersonEditor.java:178)
at com.complete.raspberry.webui.PersonEditor.buttonClick(PersonEditor.java:120)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
at java.lang.reflect.Method.invoke(Unknown Source)
at com.vaadin.event.ListenerMethod.receiveEvent(ListenerMethod.java:512)
... 36 more
Caused by: Exception [EclipseLink-4002] (Eclipse Persistence Services -  2.2.0.v20110202-r8913): org.eclipse.persistence.exceptions.DatabaseException

Answer 1

您应该使用 GenerationType.IDENTITY 为 FileDetail 使用自动递增而不是 GenerationType.AUTO 生成 pdfid实体。

@Entity
public class FileDetail implements java.io.Serializable{
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Long pdfId;
}

GenerationType.IDENTITY

Indicates that the persistence provider must assign primary keys for the entity using a database identity column.