使用EclipseLink在Postgres枚举上映射Java枚举 [英] Mapping Java enum on Postgres enum with EclipseLink

问题描述

我正在尝试使用JPA(EclipseLink实现)，并且感觉很卡住:

I am making first attempts with JPA (EclipseLink implementation) and feel quite stuck:

在PostgreSQL中，我具有以下数据库模式

In PostgreSQL I have the following db schema

CREATE TYPE mood AS ENUM ( 'sad', 'happy', 'enthusiastic' );

CREATE TABLE person (
  pk      BIGINT   PRIMARY KEY,
  name    VARCHAR  NOT NULL,
  mood    mood     NOT NULL
);

CREATE SEQUENCE person_pk_seq INCREMENT BY 100 MINVALUE 100;

这工作得很好，因为此插入显示INSERT INTO PERSON (PK, mood, name) VALUES (3, 'happy', 'Joe')(将pk设置为String并没有区别.)

Which works pretty fine, as this insert shows INSERT INTO PERSON (PK, mood, name) VALUES (3, 'happy', 'Joe') (Committing the pk as String makes no difference.)

在JPA方面，我编写了以下课程:

On the JPA side I wrote the following class:

package testdb;
import java.io.Serializable;
import javax.persistence.*;
import org.eclipse.persistence.annotations.*;

@Entity
public class Person implements Serializable {
  private static final long serialVersionUID = 1L;

  public enum Mood {
    sad, happy, enthusiastic;
  }

  @Id
  @SequenceGenerator(
    name="PERSON_PK_GENERATOR",
    sequenceName="PERSON_PK_SEQ",
    allocationSize = 100
  )
  @GeneratedValue(
    strategy=GenerationType.SEQUENCE,
    generator="PERSON_PK_GENERATOR"
  )
  public Long pk;

  @Enumerated( EnumType.STRING )
  @Column( name = "mood" )
  @ObjectTypeConverter( name = "moodConverter", objectType = Mood.class,
    dataType = String.class, conversionValues = {
      @ConversionValue( objectValue = "sad", dataValue = "sad" ),
      @ConversionValue( objectValue = "happy", dataValue = "happy" ),
      @ConversionValue( objectValue = "enthusiastic", dataValue = "enthusiastic" )
  })
  @Convert( "moodConverter" )
  public Mood mood;

  @Column( name = "name" )
  public String name;

  public static void main(String[] args) {
    EntityManagerFactory factory = Persistence.createEntityManagerFactory("TestDb.jpa.tests" );
    EntityManager em = factory.createEntityManager();

    em.getTransaction().begin();
    Person p = new Person();
    em.persist( p );
    System.out.println(p.pk);
    p.name = "Joe";
    p.mood = Mood.enthusiastic;
    em.getTransaction().commit();

    Query q = em.createQuery( "select p from Person p" );
    Person x = (Person)q.getResultList().get(0);
    System.out.println( x.pk + " :: " +x.mood );

    em.close();
  }
}

但是，此示例无法正常工作，我也不知道问题出在哪里:

However, this example is not working and I have no clue what the problem is:

[EL Warning]: 2012-06-05 15:28:20.646--UnitOfWork(845463623)--Exception [EclipseLink-4002] (Eclipse Persistence Services - 2.3.2.v20111125-r10461): org.eclipse.persistence.exceptions.DatabaseException
Internal Exception: java.sql.BatchUpdateException: Batch-Eintrag 0 INSERT INTO PERSON (PK, mood, name) VALUES ('801', 'enthusiastic', 'Joe') wurde abgebrochen.  Rufen Sie 'getNextException' auf, um die Ursache zu erfahren.
Error Code: 0
Call: INSERT INTO PERSON (PK, mood, name) VALUES (?, ?, ?)
    bind => [3 parameters bound]

当我将表person的列类型更改为varchar并删除注释@Convert和@ObjectTypeConverter时，一切也都按预期工作.

When I alter the column type of table person to varchar and remove the annotations @Convert and @ObjectTypeConverter everything is working as expected, as well.

有什么想法吗?

推荐答案

为什么使用@ObjectTypeConverter，您可以使用eclipse链接将Enumerations映射为开箱即用，如此处. @Enumerated是JSR-220的一部分，而@ObjectTypeConverter是 EclipseLink的专有扩展. JPA扩展.

Why do you use a @ObjectTypeConverter, you can map Enumerations out of the box with eclipse link as shown here. @Enumerated is part of JSR-220 whereas @ObjectTypeConverter is a proprietary extension from EclipseLink JPA Extensions.

@Enumerated(EnumType.STRING)
@Column(name = "mood")
private Mood mood;

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