在Hibernate中枚举 [英] Enumerations in Hibernate

问题描述

DAO中有一个字段通常很有用，它的值来自Java枚举。一个典型的例子是登录DAO，其中通常有一个字段将用户表征为NORMAL或ADMIN。在Hibernate中，我将使用以下两个对象以（半）类型安全的方式表示这种关系：

  class User { 
字符串用户名; 
字符串密码; 
 UserType类型; 
} 
 
 class UserType {
 private enum类型{ADMIN，NORMAL}; 
私有字符串类型; 
 
 // Setter / Getters for Hibernate 
 public void setType（String type）; 
 public String getType（）; 
 
 // Setters / Getters for user 
 public void setUserType（UserType.Type t）; 
 public UserType.Type getUserType（）; 
 
 public static UserType fromType（UserType.Type t）; 
} 
  

这个方法可行，但我发现UserType类很笨拙，只需要太多的官僚作风存储一些值。理想情况下，Hibernate应直接支持enum字段，并创建一个额外的表来存储枚举值。

我的问题是：有没有什么办法直接映射枚举类休眠？如果没有，我的模式代表枚举是否足够好，或者我错过了什么？人们使用什么其他模式？

使用hibernate或JPA注解：
$ b

解决方案

code> class User {
@Enumerated（EnumType.STRING）
UserType type
}

UserType只是一个标准的java 5枚举。

我无法想象这仅仅局限于注释，但实际上我不知道如何用hbm文件来做到这一点。它可能是非常依赖版本，我猜，但我非常确定，需要休眠3.2+。

编辑：它可能在hbm，但是有点混乱，看看这个论坛主题

It is often useful to have a field in a DAO whose value comes from a Java enumeration. A typical example is a login DAO where you usually have a field that characterises the user as "NORMAL" or "ADMIN". In Hibernate, I would use the following 2 objects to represent this relationship in a (semi-)typesafe way:

class User {
    String username;
    String passwd;
    UserType type;
}

class UserType {
    private enum Type {ADMIN, NORMAL};
    private String type;

    //Setters/Getters for Hibernate
    public void setType(String type);
    public String getType();

    //Setters/Getters for user
    public void setUserType(UserType.Type t);
    public UserType.Type getUserType();

    public static UserType fromType(UserType.Type t);
}

This works, but I find the UserType class ungly and requiring too much bureaucracy just to store a couple of values. Ideally, Hibernate should support enum fields directly and would create an extra table to store the enumeration values.

My question is: Is there any way to directly map an enumeration class in Hibernate? If not, is my pattern for representing enumerations good enough or am I missing something? What other patterns do people use?

解决方案

using hibernate or JPA annotations:

class User {
   @Enumerated(EnumType.STRING)
   UserType type
}

UserType is just a standard java 5 enum.

I can't imagine this is just limited to just annotations but I don't actually know how to do this with hbm files. It may be very version dependant, I'm guessing but I'm pretty sure that hibernate 3.2+ is required.

edit: it is possible in a hbm, but is a little messy, have a look at this forum thread

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