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我有一个非常简单的基于控制台（不是应用程序服务器部署）的 JPA 程序，我针对 EclipseLink 和 Hibernate 提供程序进行了测试。所有代码都是 JPA，所以我想我可以毫无问题地切换提供程序。但是，当使用 Hibernate 作为提供程序时程序成功，但在 EclipseLink 中失败。

关键部分是这个（我在防火墙后面，所以我看不到格式，因为“SO 需要来自另一个域的 JavaScript ......”所以如果格式不正确，我很抱歉 - 我会在家里进行格式化）：

em.getTransaction().begin();
Employee emp = service.createEmployee(id, "John Doe", 45000,1);
em.getTransaction().commit();                                        
System.out.println("Persisted "+emp);
em.getTransaction().begin();
em.getTransaction().commit();

我曾经在第二个空事务中做一些事情，但是在缩小问题范围时，我注意到即使我只是 begin() 和 commit() 立即不做任何事情，它也会失败。有趣的部分是 EclipseLink（请参阅帖子底部的堆栈跟踪）似乎抱怨实体 Specialty 的 id 属性正在更新，尽管它没有。

Employee实体有一个Specialty实体的外键（每个Employee都有一个Specialty），即来自Employee的多对一​​关系：

 @Entity
 public class Employee {
 @Id                                                            
 @Basic(optional = false)                                       
 @NotNull                                                       
 private int id;                                                
 private String name;                                           
 private long salary;                                           
 @JoinColumn(name = "spc_id", referencedColumnName = "id")      
 @ManyToOne(optional = false)                                   
 private Specialty spcId;
 ...}

并且专业类定义为：

@Entity                                                  
public class Specialty {                                 
@Id                                                  
@Basic(optional = false)                             
@NotNull                                             
private int id;
... }

当使用 Hibernate 作为 JPA 提供程序时，代码可以顺利执行。使用 EclipseLink 时，它会失败，并在本文底部找到堆栈跟踪。

更新：经过进一步的实验，我发现以下代码适用于两个提供程序：

em.getTransaction().begin();                                      
Employee emp = service.createEmployee(id, "John Doe", 45000, 1);  
em.getTransaction().commit();                                     
System.out.println("Persisted " + emp);                           
EntityManager em2 = emf.createEntityManager();
em2.getTransaction().begin();                                     
em2.getTransaction().commit();                                    
em2.close();

这仍然不能解释为什么 EclipseLink 在尝试在同一个实体管理器对象上开始（）/提交（）事务时失败（em - 请参阅帖子开头的代码），以及为什么它会失败并显示如此神秘的消息（抱怨关于正在更新的专业类的主键）。

堆栈跟踪：

[java] [EL Info]: 2012-07-12 11:21:09.453--ServerSession(23846608)--EclipseLink, version: Eclipse Persistence Services - 2.4.0.v20120608-r11652
 [java] [EL Info]: connection: 2012-07-12 11:21:09.59--ServerSession(23846608)--file:/home/mperdikeas/playground/jpa/01-employee-job/prj/use/build/employeetest.jar_EmployeeService login successful
 [java] Exception in thread "main" javax.persistence.RollbackException: Exception [EclipseLink-7251] (Eclipse Persistence Services - 2.4.0.v20120608-r11652): org.eclipse.persistence.exceptions.ValidationException
 [java] Exception Description: The attribute [id] of class [mp.Specialty] is mapped to a primary key column in the database. Updates are not allowed.
 [java]     at org.eclipse.persistence.internal.Persisted mp.Employee@ea70f2
 [java] [EL Warning]: 2012-07-12 11:21:09.735--UnitOfWork(32118258)--Exception [EclipseLink-7251] (Eclipse Persistence Services - 2.4.0.v20120608-r11652): org.eclipse.persistence.exceptions.ValidationException
 [java] Exception Description: The attribute [id] of class [mp.Specialty] is mapped to a primary key column in the database. Updates are not allowed.
 [java] [EL Info]: connection: 2012-07-12 11:21:09.738--ServerSession(23846608)--file:/home/mperdikeas/playground/jpa/01-employee-job/prj/use/buildjpa.transaction.EntityTransactionImpl.commitInternal(EntityTransactionImpl.java:102)
 [java]     at org.eclipse.persistence.internal.jpa.transaction.EntityTransactionImpl.commit(EntityTransactionImpl.java:63)
 [java]     at mp.EmployeeTest.main(EmployeeTest.java:29)
 [java] Caused by: Exception [EclipseLink-7251] (Eclipse Persistence Services - 2.4.0.v20120608-r11652): org.eclipse.persistence.exceptions.ValidationException
 [java] Exception Description: The attribute [id] of class [mp.Specialty] is mapped to a primary key column in the database. Updates are not allowed.
 [java]     at org.eclipse.persistence.exceptions.ValidationException.primaryKeyUpdateDisallowed(ValidationException.java:2458)
 [java]     at org.eclipse.persistence.mappings.foundation.AbstractDirectMapping.writeFromObjectIntoRowWithChangeRecord(AbstractDirectMapping.java:1214)
 [java]     at org.eclipse.persistence.internal.descriptors.ObjectBuilder.buildRowForUpdateWithChangeSet(ObjectBuilder.java:1378)
 [java]     at org.eclipse.persistence.internal.queries.DatabaseQueryMechanism.updateObjectForWriteWithChangeSet(DatabaseQueryMechanism.java:1003)
 [java]     at org.eclipse.persistence.queries.UpdateObjectQuery.executeCommitWithChangeSet(UpdateObjectQuery.java:84)
 [java]     at org.eclipse.persistence.internal.queries.DatabaseQueryMechanism.executeWriteWithChangeSet(DatabaseQueryMechanism.java:286)
 [java]     at org.eclipse.persistence.queries.WriteObjectQuery.executeDatabaseQuery(WriteObjectQuery.java:58)
 [java]     at org.eclipse.persistence.queries.DatabaseQuery.execute(DatabaseQuery.java:852)
 [java]     at org.eclipse.persistence.queries.DatabaseQuery.executeInUnitOfWork(DatabaseQuery.java:751)
 [java]     at org.eclipse.persistence.queries.ObjectLevelModifyQuery.executeInUnitOfWorkObjectLevelModifyQuery(ObjectLevelModifyQuery.java:108)
 [java]     at org.eclipse.persistence.queries.ObjectLevelModifyQuery.executeInUnitOfWork(ObjectLevelModifyQuery.java:85)
 [java]     at org.eclipse.persistence.internal.sessions.UnitOfWorkImpl.internalExecuteQuery(UnitOfWorkImpl.java:2875)
 [java]     at org.eclipse.persistence.internal.sessions.AbstractSession.executeQuery(AbstractSession.java:1602)
 [java]     at org.eclipse.persistence.internal.sessions.AbstractSession.executeQuery(AbstractSession.java:1584)
 [java]     at org.eclipse.persistence.internal.sessions.AbstractSession.executeQuery(AbstractSession.java:1535)
 [java]     at org.eclipse.persistence.internal.sessions.CommitManager.commitChangedObjectsForClassWithChangeSet(CommitManager.java:265)
 [java]     at org.eclipse.persistence.internal.sessions.CommitManager.commitAllObjectsWithChangeSet(CommitManager.java:128)
 [java]     at org.eclipse.persistence.internal.sessions.AbstractSession.writeAllObjectsWithChangeSet(AbstractSession.java:3914)
 [java]     at org.eclipse.persistence.internal.sessions.UnitOfWorkImpl.commitToDatabase(UnitOfWorkImpl.java:1419)
 [java]     at org.eclipse.persistence.internal.sessions.RepeatableWriteUnitOfWork.commitToDatabase(RepeatableWriteUnitOfWork.java:634)
 [java]     at org.eclipse.persistence.internal.sessions.UnitOfWorkImpl.commitToDatabaseWithChangeSet(UnitOfWorkImpl.java:1509)
 [java]     at org.eclipse.persistence.internal.sessions.RepeatableWriteUnitOfWork.commitRootUnitOfWork(RepeatableWriteUnitOfWork.java:266)
 [java]     at org.eclipse.persistence.internal.sessions.UnitOfWorkImpl.commitAndResume(UnitOfWorkImpl.java:1147)
 [java]     at org.eclipse.persistence.internal.jpa.transaction.EntityTransactionImpl.commitInternal(EntityTransactionImpl.java:84)
 [java]     ... 2 more
 [java] /employeetest.jar_EmployeeService logout successful
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3 回答 3

2

EclipseLink 不允许您更新 PK（如果此 PK 没有任何 FK，某些 DBMS 允许这样做）

有2个解决方法：

  1. 尝试删除旧记录，然后插入新记录。
  2. 使用代理 PK 代替业务 PK（您仍然可以在业务 PK 字段上添加唯一约束），在这种情况下，虚拟代理键不会更改，这里是两个键之间的比较
于 2013-07-21T13:54:56.920 回答
0

它可能是：

@Entity                                                  
public class Specialty {                                 
@Id                                                  
@Basic(optional = false)                             
@NotNull
@GeneratedValue(strategy = GenerationType.AUTO)                                         
private int id;
... }
于 2013-11-18T11:23:18.483 回答
0

<property name="eclipselink.weaving.internal" value="false"/>按照http://blogs.nologin.es/rickyepoderi/index.php?/archives/95-Weaving-Problem-in-EclipseLink.html尝试。

于 2015-08-17T17:32:04.037 回答