jpa独立自定义类型映射/ javax.persistence.x替代org.hibernate.annotations.Type和org.hibernate.annotations.TypeDef [英] jpa independent custom type mapping / javax.persistence.x alternative to org.hibernate.annotations.Type and org.hibernate.annotations.TypeDef

问题描述

在包含类型的列 date 的数据库中有一个表 GameCycle 编号。此栏中的值为8位数字，代表反向日期，如' 20130301 '。映射到这张表上，我有一个类 GameCycle ，它包含一个类型为 java.util.Date 的受保护字段iDate。该字段使用自定义类型映射注释为' @Type（type =inverseDate）'。类 Gamecycle 用' @TypeDef（name =inverseDate，typeClass = InverseDateType.class）注释'

  import org.hibernate.annotations.Type; 
 import org.hibernate.annotations.TypeDef; 
 
 @Entity 
 @TypeDef（name =inverseDate，typeClass = InverseDateType.class）
 @Table（name =GAMECYCLE）
 public class GameCycle implements可比较的< GameCycle> ;,可序列化的
 {
 @Type（type =inverseDate）
 @Column（name =GC_DATE，nullable = false）
保护日期iDate = null ; 
 ... 
  

很明显，导入让我使用hibernate作为jpa实现，所以我的问题是：

有没有办法摆脱hibernate注释并使用纯 javax.persistence 解决方案？

解决方案

JPA规范的当前版本不支持自定义类型映射。这是未来JPA 2.1最受欢迎的功能之一。

如果你真的想摆脱Hibernate特有的注释，唯一能做的就是映射你的字段作为字符串并且手动执行必要的转换（在getters / setters中）。然而在实践中，几乎每个大的JPA基于应用程序使用持久性提供程序的一些特定于实现的功能，因此我认为在这种情况下避免依赖Hibernate确实很重要。

I have a table GameCycle in a db that holds a column date of type number. The values in this column are 8-digit numbers representing an inverse date like '20130301'. Mapped onto this table i have a class GameCycle that holds a protected field iDate of type java.util.Date. That field is annotated '@Type(type = "inverseDate")', using a custom type mapping. The class Gamecycle is annotated with '@TypeDef(name = "inverseDate", typeClass = InverseDateType.class)'

import org.hibernate.annotations.Type;
import org.hibernate.annotations.TypeDef;

@Entity
@TypeDef(name = "inverseDate", typeClass = InverseDateType.class)
@Table(name = "GAMECYCLE")
public class GameCycle implements Comparable<GameCycle>, Serializable
{
    @Type(type = "inverseDate")
    @Column(name = "GC_DATE", nullable = false)
    protected Date iDate = null;
    ...

Obviously, the imports bind me to using hibernate as a jpa implementation so my question is:

Is there a way to get rid of the hibernate annotations and do the same custom type mapping using a pure javax.persistence solution ?

解决方案

No. Current version of JPA specification doesn't support custom type mappings. It's one of the most wanted features for future JPA 2.1.

If you really want to get rid of Hibernate-specific annoations, the only thing you can do is to map your field as String and perform necessary conversion manually (in getters/setters).

But in practice almost every large JPA-based application uses some implementation-specific features of persistence provider, therefore I don't think that avoiding dependency on Hibernate in this case really matters.

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