双向问题ManyToOne

Question

我有两个实体:Message和GeneratedMemberMessage.这里有更多的字段,而不是我在代码中显示的字段,但这些字段应足以提供我的问题的上下文.

我正在尝试做一个简单的双向OneToMany关系,从我读过的所有内容来看,这就是它要做的事情.你会注意到我正在使用复合键.

我得到以下错误和堆栈跟踪.我见过其他人在互联网上遇到过这个问题,但没有人能找到适合我的解决方案.有没有人在这看到问题？

正如ST建议的那样,我在WAS 7.0中使用openJPA 1.2.2.我正在使用RAD 7.5.4和EJB 3.0进行开发.

Message.java

@Entity
@Table(schema="dbo", name="Messages")
public class Message implements Serializable {

  @Embeddable
  public static class MessagePK implements Serializable {
    @Column(name="SourceApplication")
    String sourceApplication;

    @GeneratedValue(strategy=GenerationType.IDENTITY)
    @Column(name="MessageId")
    BigDecimal messageId;

    //Getters and setters here

  }


  @EmbeddedId
  MessagePK pk = new MessagePK();
  ...

  @OneToMany(cascade={CascadeType.ALL}, mappedBy="message")
  List<GeneratedMemberMessage> generatedMemberMessages = new ArrayList<GeneratedMemberMessage>();

  ...

}

GeneratedMemberMessage.java

@Entity
@Table(schema="dbo", name="GeneratedMemberMessages")
public class GeneratedMemberMessage implements Serializable {
  @Embeddable
  public static class GMMPK implements Serializable {

    @Column(name="SourceApplication")
    String sourceApplication;

    @Column(name="MessageId")
    int messageId;

    @Column(name="MessageGenerationDateTime")
    Date messageGenerationDateTime;

    //Getters and setters here

  }
  ...

  @ManyToOne(optional = true)
  @JoinColumns({  
    @JoinColumn(name="sourceApplication", referencedColumnName="SourceApplication"),  
    @JoinColumn(name="messageId", referencedColumnName="MessageId")
  }) 
  Message message;

  ...

}

我的EJB方法

public Message newMessage(String sourceApplication, String text, int priority, String type){
    Message m = new Message(sourceApplication);
    m.setMessageText(text);
    m.setMessagePriority(priority);
    m.setMessageType(type);
    m.setSysLstUpdtUserId("me");    
    em.persist(m);
    return m;
}

堆栈跟踪

[3/17/10 14:55:05:457 EDT] 0000001e SystemErr     R javax.ejb.EJBException: See nested exception; nested exception is: <openjpa-1.2.2-SNAPSHOT-r422266:778978M-OPENJPA-975 fatal user error> org.apache.openjpa.persistence.ArgumentException: Field "com.bcbst.bamp.jpa.Message.generatedMemberMessages" cannot declare that it is mapped by another field. Its mapping strategy (org.apache.openjpa.jdbc.meta.strats.HandlerFieldStrategy) does not support mapping by another field.
[3/17/10 14:55:05:457 EDT] 0000001e SystemErr     R Caused by: <openjpa-1.2.2-SNAPSHOT-r422266:778978M-OPENJPA-975 fatal user error> org.apache.openjpa.persistence.ArgumentException: Field "com.bcbst.bamp.jpa.Message.generatedMemberMessages" cannot declare that it is mapped by another field. Its mapping strategy (org.apache.openjpa.jdbc.meta.strats.HandlerFieldStrategy) does not support mapping by another field.
[3/17/10 14:55:05:457 EDT] 0000001e SystemErr     R     at org.apache.openjpa.jdbc.meta.strats.AbstractFieldStrategy.assertNotMappedBy(AbstractFieldStrategy.java:59)
[3/17/10 14:55:05:457 EDT] 0000001e SystemErr     R     at org.apache.openjpa.jdbc.meta.strats.HandlerFieldStrategy.map(HandlerFieldStrategy.java:71)
[3/17/10 14:55:05:457 EDT] 0000001e SystemErr     R     at org.apache.openjpa.jdbc.meta.FieldMapping.setStrategy(FieldMapping.java:121)
[3/17/10 14:55:05:457 EDT] 0000001e SystemErr     R     at org.apache.openjpa.jdbc.meta.RuntimeStrategyInstaller.installStrategy(RuntimeStrategyInstaller.java:80)
[3/17/10 14:55:05:457 EDT] 0000001e SystemErr     R     at org.apache.openjpa.jdbc.meta.FieldMapping.resolveMapping(FieldMapping.java:454)
[3/17/10 14:55:05:457 EDT] 0000001e SystemErr     R     at org.apache.openjpa.jdbc.meta.FieldMapping.resolve(FieldMapping.java:419)
[3/17/10 14:55:05:457 EDT] 0000001e SystemErr     R     at org.apache.openjpa.jdbc.meta.ClassMapping.resolveNonRelationMappings(ClassMapping.java:879)
[3/17/10 14:55:05:457 EDT] 0000001e SystemErr     R     at org.apache.openjpa.jdbc.meta.MappingRepository.prepareMapping(MappingRepository.java:339)
...

Answer 1

我今天遇到了样本问题,并找到了适合我的解决方案.

我把类名添加到了persistence.xml.尝试将Message类添加到persistence.xml使用中<class>Message</class>.

Answer 2

为什么将 MessagePK 类设为静态？这难道不是问题的一部分吗？