Hibernate @AttributeOverride 适用于实体但不适用于属性

Question

Hibernate 版本 5.4.29（独立测试）或 5.4.28（使用 SpringBoot 2.4.3 测试）

以下型号： 可嵌入Book

import javax.persistence.Embeddable;
    
@Embeddable
public class Book {
    public Book() { }
        
    private String name = "";
    private String author = "";
    
    // ctors, getters, setters removed for brevity 
        
}

事件嵌入 2 Books（book 和 ebook）

@Entity
@Table( name = "EVENTS" )
/*@AttributeOverrides({
    @AttributeOverride(name = "book.name", column = @Column(name = "book_title")), 
    @AttributeOverride(name = "book.author", column = @Column(name = "book_author")),
    @AttributeOverride(name = "ebook.name", column = @Column(name = "ebook_title")), 
    @AttributeOverride(name = "ebook.author", column = @Column(name = "ebook_author"))
})*/
public class Event {
   private Long id;
   private String title;
   private Date date;
        
   @Embedded
   @AttributeOverrides({
      @AttributeOverride(name = "name", column = @Column(name = "book_title")), 
      @AttributeOverride(name = "author", column = @Column(name = "book_author")),
   })
   private Book book = new Book();
        
   @Embedded
   @AttributeOverrides({
      @AttributeOverride(name = "name", column = @Column(name = "ebook_title")), 
      @AttributeOverride(name = "author", column = @Column(name = "ebook_author")),
   })
   private Book ebook = new Book();
    
   // ctors, getters, setters removed for brevity 
}

当尝试在实体上配置 @AttributeOverride 时（如 cmets 所示 - 它可以工作），但是当在 Book 类型的具体 @Embedded 属性上时它不起作用。 收到以下错误：

    Caused by: org.hibernate.MappingException: Repeated column in mapping for entity: com.example.demo.Event.Event column: author (should be mapped with insert="false" update="false")
        at org.hibernate.mapping.PersistentClass.checkColumnDuplication(PersistentClass.java:862) ~[hibernate-core-5.4.28.Final.jar:5.4.28.Final]
        at org.hibernate.mapping.PersistentClass.checkPropertyColumnDuplication(PersistentClass.java:880) ~[hibernate-core-5.4.28.Final.jar:5.4.28.Final]
        at org.hibernate.mapping.PersistentClass.checkPropertyColumnDuplication(PersistentClass.java:876) ~[hibernate-core-5.4.28.Final.jar:5.4.28.Final]
        at org.hibernate.mapping.PersistentClass.checkColumnDuplication(PersistentClass.java:902) ~[hibernate-core-5.4.28.Final.jar:5.4.28.Final]
        at org.hibernate.mapping.PersistentClass.validate(PersistentClass.java:634) ~[hibernate-core-5.4.28.Final.jar:5.4.28.Final]
        at org.hibernate.mapping.RootClass.validate(RootClass.java:267) ~[hibernate-core-5.4.28.Final.jar:5.4.28.Final]
        at org.hibernate.boot.internal.MetadataImpl.validate(MetadataImpl.java:354) ~[hibernate-core-5.4.28.Final.jar:5.4.28.Final]
        at org.hibernate.internal.SessionFactoryImpl.<init>(SessionFactoryImpl.java:298) ~[hibernate-core-5.4.28.Final.jar:5.4.28.Final]
        at org.hibernate.boot.internal.SessionFactoryBuilderImpl.build(SessionFactoryBuilderImpl.java:468) ~[hibernate-core-5.4.28.Final.jar:5.4.28.Final]
        at org.hibernate.jpa.boot.internal.EntityManagerFactoryBuilderImpl.build(EntityManagerFactoryBuilderImpl.java:1259) ~[hibernate-core-5.4.28.Final.jar:5.4.28.Final]

持久化实体

Event e = new Event( "A booked event", new Date() );
e.getBook().setAuthor("Jora K Jr");
e.getBook().setName("Book Name");
entityManager.persist( e3 );

我做错了什么？在 Hibernate 4 中，AFAIR - 它起作用了。

Answer 1

您很可能会收到此错误，因为您尝试混淆 access strategies 和休眠只是忽略您的 @AttributeOverride 注释。默认情况下，@Id 注解的放置给出了默认的访问策略。

因此，请尝试以这种方式更正您的实体映射：

@Entity
@Table( name = "EVENTS" )
public class Event {

    @Id
    private Long id;

    // ...
    
    @Embedded
    @AttributeOverrides({
        @AttributeOverride(name = "name", column = @Column(name = "book_title")), 
        @AttributeOverride(name = "author", column = @Column(name = "book_author")),
    })
    private Book book = new Book();
    
    @Embedded
    @AttributeOverrides({
        @AttributeOverride(name = "name", column = @Column(name = "ebook_title")), 
        @AttributeOverride(name = "author", column = @Column(name = "ebook_author")),
    })
    private Book ebook = new Book();

    //ctors, getters, setters removed for brevity 

}

附：但是，如果您需要，您可以使用@Access 注解override 默认访问策略。