Java JPA2:Enum与AttributeConverter组合的ElementCollection

我试图结合两个概念：

• 存储实体的一对多关系中的枚举（使用

  @ElementCollection

  ，

  @CollectionTable

  ）
• 不是通过字符串或序号，而是通过唯一ID（使用

  @AttributeConverter

  ）持久化枚举

单独使用它们应该可以很好地工作（根据文档判断），但是当我将它们组合在一起时，在构建过程中会出现错误

以下是实体：

@Entity
@Table(name = "push_tokens")
public class PushTokenDAO implements Serializable {

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

    @ElementCollection(targetClass = NotificationType.class, fetch = FetchType.EAGER)
    @Convert(converter = NotificationTypeConverter.class)
    @CollectionTable(
            name = "notificationtypes_of_tokens",
            joinColumns = @JoinColumn(name = "fk_tokenIdx")
    )
    @Column(name = "notificationType")
    private List<NotificationType> notificationTypes;

    /* ... */

}

转换器：

import javax.persistence.AttributeConverter;
import javax.persistence.Converter;

@Converter(autoApply = true)
public class NotificationTypeConverter implements AttributeConverter<NotificationType, Integer> {

    @Override
    public Integer convertToDatabaseColumn(NotificationType x) {
        return x.getCode();
    }

    @Override
    public NotificationType convertToEntityAttribute(Integer y) {
        return NotificationType.parse(y);
    }

}

问题发生在EclipseLink的静态编织过程中，这是构建过程的一部分：

Failed to execute goal de.empulse.eclipselink:staticweave-maven-plugin:1.0.0:weave (default) 
on project skp-server: Execution default of goal de.empulse.eclipselink:staticweave-maven-plugin:1.0.0:weave 
failed: Exception [EclipseLink-28018] (Eclipse Persistence Services - 2.6.0.v20150309-bf26070):
    org.eclipse.persistence.exceptions.EntityManagerSetupException
Exception Description: Predeployment of PersistenceUnit [skp-server-PU] failed.
Internal Exception: Exception [EclipseLink-7351] (Eclipse Persistence Services - 2.6.0.v20150309-bf26070):
    org.eclipse.persistence.exceptions.ValidationException
Exception Description: The converter class [com.skalio.skaliopush.db.NotificationTypeConverter] 
    specified on the mapping attribute [notificationTypes] from the class 
    [com.skalio.skaliopush.db.entity.PushTokenDAO] was not found. Please ensure the converter 
    class name is correct and exists with the persistence unit definition.

如果我没有在实体中特别引用转换器（省略

@Convert

），则转换不会完成；枚举映射到其序号。这不是我想要的

---

仅供参考：代码运行在JavaSE虚拟机上，而不是应用服务器或其他东西上。我必须在

persistence.xml

中指定每个实体类。解决方案与

@ElementCollection

、枚举或与

@AttributeConverter

的组合无关

相反，答案在于这个问题。错误消息也以这种方式暗示（'未找到转换器…'）

---

在

persistence.xml

中指定转换器类后，编织工作正常，代码生成，并按预期运行。总而言之：根据上面的代码，将

@ElementCollection

、Enum和

@AttributeConverter

组合使用效果很好。

解决方案与

@ElementCollection

、Enum或与

@AttributeConverter

的组合无关

相反，答案在于这个问题。错误消息也以这种方式暗示（'未找到转换器…'）

在

persistence.xml

中指定转换器类后，编织工作正常，代码生成，并按预期运行。总之：根据上面的代码，将

@ElementCollection

、Enum和

@AttributeConverter

组合在一起就可以了。

CREATE TABLE `notificationtypes_of_tokens` (
  `fk_tokenIdx` bigint(11) unsigned NOT NULL,
  `notificationType` int(11) unsigned NOT NULL,
  PRIMARY KEY (`fk_tokenIdx`,`notificationType`),
  KEY `fk_tokenIdx` (`fk_tokenIdx`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;

Failed to execute goal de.empulse.eclipselink:staticweave-maven-plugin:1.0.0:weave (default) 
on project skp-server: Execution default of goal de.empulse.eclipselink:staticweave-maven-plugin:1.0.0:weave 
failed: Exception [EclipseLink-28018] (Eclipse Persistence Services - 2.6.0.v20150309-bf26070):
    org.eclipse.persistence.exceptions.EntityManagerSetupException
Exception Description: Predeployment of PersistenceUnit [skp-server-PU] failed.
Internal Exception: Exception [EclipseLink-7351] (Eclipse Persistence Services - 2.6.0.v20150309-bf26070):
    org.eclipse.persistence.exceptions.ValidationException
Exception Description: The converter class [com.skalio.skaliopush.db.NotificationTypeConverter] 
    specified on the mapping attribute [notificationTypes] from the class 
    [com.skalio.skaliopush.db.entity.PushTokenDAO] was not found. Please ensure the converter 
    class name is correct and exists with the persistence unit definition.