java - JPA 2 Hibernate 映射与主键中的复合键使用@IdClass 与 3 层结构

Question

这个问题非常类似于:JPA (Hibernate, EclipseLink) mapping: why doesn't this code work (chain of 2 relationships using JPA 2.0, @EmbeddedId composite PK-FK)?

实际上我唯一的(从我发现的意义来看)区别是我使用 @IdClass 并且我很可能无法切换到与 hibernate 不同的提供程序。

但无论如何这里是代码(删除了不重要的部分):

PermissionContextType.java:

@Entity
@IdClass(PermissionContextTypePk.class)
public class PermissionContextType{
   @Id    
   private String id;    

   @Id
   @JoinColumn (name = "PROJECT", referencedColumnName = "ID")
   @ManyToOne ()
   private Project project;

   public static class PermissionContextTypePk implements Serializable{
       public String project;
       public String id;
       // ... eq and hashCode here ...
   }

}

PermissionContext.java:

@Entity
@IdClass(PermissionContextPk.class)
public class PermissionContext{
   @Id
   private String id;

   @Id
   @JoinColumns ({
            @JoinColumn (name = "PROJECT", referencedColumnName = "PROJECT"),
            @JoinColumn (name = "PERMISSIONCONTEXTTYPE", referencedColumnName = "ID")
        })
   @ManyToOne
   private PermissionContextType permissionContextType;

   public static class PermissionContextPk implements Serializable{
      public String id;
      public PermissionContextTypePk permissionContextType;
      // ... eq and hashCode here ...
   }
}

Permission.java:

@Entity
@IdClass(PermissionPk.class)
public class Permission{

   @Id
   private String id;

   @Id
   @JoinColumns ({
            @JoinColumn (name = "PROJECT", referencedColumnName = "PROJECT"),
            @JoinColumn (name = "PERMISSIONCONTEXTTYPE", referencedColumnName = "PERMISSIONCONTEXTTYPE"),
            @JoinColumn (name = "PERMISSIONCONTEXT", referencedColumnName = "ID")
        })
   @ManyToOne
   private PermissionContext permissionContext;

   public static class PermissionPk implements Serializable{
      public String id;        
      public PermissionContextPk permissionContext;
      // ... eq and hashCode here ...
   }
}

我得到的是:

 org.hibernate.AssertionFailure: Unexpected nested component on the referenced entity when mapping a @MapsId: PermissionContext 
    Caused by: org.hibernate.AssertionFailure: org.hibernate.AssertionFailure: Unexpected nested component on the referenced entity when mapping a @MapsId: PermissionContext

有谁知道这是否是一个 hibernate 错误，我应该将其发布到他们的问题跟踪系统上(并祈祷我能够更新到给定的 hibernate 版本)或者我绑定(bind)实体的方式是否存在根本性错误？

我已经用 EAP 6.1 (4.2.0) 和 wildfly 上的 hibernate 实现检查了它(真的不知道是哪一个。)

Answer 1

好的，这就是我目前所发现的:

谢谢我的 friend :https://hibernate.atlassian.net/browse/HHH-5764这很可能是造成这种行为的原因。

我找到了解决方法:

权限.java:

@Entity
@IdClass(PermissionPk.class)
public class Permission{

   @Id
   private String id;

// for the next 3 fields there are no public acessors, so the public API of the class was not changed !
   @Id
   @Column(name = "PROJECT")
   private String projectId;

   @Id
   @Column(name = "PERMISSIONCONTEXTTYPE")
   private String permissionContextTypeId;

   @Id
   @Column(name = "PERMISSIONCONTEXT")
   private String permissionContextId;


   @JoinColumns ({
            @JoinColumn (name = "PROJECT", referencedColumnName = "PROJECT", updatable = false, insertable = false),
            @JoinColumn (name = "PERMISSIONCONTEXTTYPE", referencedColumnName = "PERMISSIONCONTEXTTYPE", updatable = false, insertable = false),
            @JoinColumn (name = "PERMISSIONCONTEXT", referencedColumnName = "ID", updatable = false, insertable = false)
        })
   @ManyToOne
   private PermissionContext permissionContext;

   public static class PermissionPk implements Serializable{      
// previously they where private as well, but removed public constructor for the sake of simplicity of the question - so no changes where necesary in public API of the class !
      private String id;        
      private String projectId;        
      private String permissionContextTypeId;
      private String permissionContextId;

   public PermissionPk () {}

    public PermissionPk (String aId, PermissionContextPk aPermissionContext) {
        this.id = aId;
        permissionContextId = aPermissionContext.id;
        permissionContextTypeId = aPermissionContext.permissionContextType.id;
        projectId = aPermissionContext.permissionContextType.project;
    }  
... eq and hashCode here ...
   }
}

这个变通办法的好处是它不会以任何方式改变类的公共(public) API(唯一的变化是我需要使 Pk 的上下文和上下文类型中的字段对 PermissionPk 可见 - 它们之前是私有(private)的，只有一个公共(public)构造函数 [但再次简化了问题])，也没有改变 jpql 查询，并且同时，变通办法是可扩展的(可扩展到任何层数 - 只要每个偶数 pk 不包含另一个 pk)，因此如果错误得到解决，将很容易删除变通办法。

我仍然很乐意接受任何关于我的解决方法或问题本身的评论。