大家好,
我试图从遗留数据库中构建所有 jpa 实体。我有一个反复出现的问题:一些“主要”实体有一个“翻译”集合,其中主键是“主要”+“语言”标识符的键。语言存储在数据库和枚举中,以方便处理。
我使用的 JPA 实现是 Hibernate 4。
以下是当前的实现:
主要:(留言)
@Entity
@Table(name="MESSAGES")
@NamedQueries({
public class Message implements Serializable {
@Id
@SequenceGenerator(name="MESSAGES_MESSAGEID_GENERATOR", sequenceName="SEQ_MSG_messageID")
@GeneratedValue(strategy=GenerationType.SEQUENCE, generator="MESSAGES_MESSAGEID_GENERATOR")
@Column(name="messageId")
private long id;
@OneToMany(mappedBy="message", fetch=FetchType.EAGER)
private Set<MessageDesc> descriptions;
}
翻译:(MessageDesc)
@Entity
@Table(name="MESSAGEDESCS")
public class MessageDesc implements Serializable, Translatable {
@EmbeddedId
private MessageDescPK id;
@NotNull
@Enumerated(EnumType.ORDINAL)
@Column(name = "LANGUAGEID")
private LanguageEnum language;
@NotNull
@ManyToOne
@JoinColumn(name="MESSAGEID")
private Message message;
}
翻译复合键:(MessageDescPK)
@Embeddable
public class MessageDescPK implements Serializable {
@Column(name="messageid", nullable = false, insertable = false)
private long message;
@Column(name="languageid", nullable = false, insertable = false)
private int language;
}
语言:(LanguageEnum)
public enum LanguageEnum {
FRENCH(0, "FR"),
DUTCH(1, "NL");
private int id;
private String desc;
}
问题是,当尝试在描述上保留带有一些翻译的主(消息)实体以及设置了语言和消息的翻译时,我不断收到以下异常:
org.springframework.orm.jpa.JpaSystemException: org.hibernate.id.IdentifierGenerationException: null id generated for:class something.persistence.entity.message.MessageDesc; nested exception is javax.persistence.PersistenceException: org.hibernate.id.IdentifierGenerationException: null id generated for:class something.persistence.entity.message.MessageDesc
at org.springframework.orm.jpa.EntityManagerFactoryUtils.convertJpaAccessExceptionIfPossible(EntityManagerFactoryUtils.java:321)
at org.springframework.orm.jpa.AbstractEntityManagerFactoryBean.translateExceptionIfPossible(AbstractEntityManagerFactoryBean.java:403)
at org.springframework.dao.support.ChainedPersistenceExceptionTranslator.translateExceptionIfPossible(ChainedPersistenceExceptionTranslator.java:58)
at org.springframework.dao.support.DataAccessUtils.translateIfNecessary(DataAccessUtils.java:213)
at org.springframework.dao.support.PersistenceExceptionTranslationInterceptor.invoke(PersistenceExceptionTranslationInterceptor.java:163)
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:172)
at org.springframework.data.jpa.repository.support.CrudMethodMetadataPostProcessor$CrudMethodMetadataPopulatingMethodIntercceptor.invoke(CrudMethodMetadataPostProcessor.java:111)
我不明白为什么在 messageDesc 实例上设置语言和消息(已经持久化)后 PK 为空。任何帮助,评论,线索将不胜感激。
谢谢!