我正在尝试使用注释设置多对多关系。这是我的实体
@Entity
public class Publisher{
@Id
public int id;
public String name;
}
@Entity
public class PublisherBook{
@Id
public int id;
@ManyToOne(cascade=CascadeType.ALL)
@JoinColumn(name="bookId",nullable=false)
public Book book;
@ManyToOne(cascade=CascadeType.ALL)
@JoinColumn(name="publisherId",nullable=false)
public Publisher Publisher;
}
@Entity
public class Book{
@Id
public int id;
public String name;
@OneToMany(fetch=FetchType.EAGER, mappedBy="book")
public Set<BookAuthor> authors;
}
@Entity
public class BookAuthor{
@Id
public int id;
@ManyToOne(cascade=CascadeType.ALL)
@JoinColumn(name="bookId",nullable=false)
public Book book;
@ManyToOne(cascade=CascadeType.ALL)
@JoinColumn(name="authorId",nullable=false)
public Author author;
}
@Entity
public class Authors{
@Id
public int id;
public String name;
}
这是我为实体拥有的一组样本数据
Author:( id,name)
1, Author 1
2, Author 2
3, Author 3
Book: (id, name )
1, Book 1
2, Book 2
3, Book 3
Publisher(id,name)
1, Publisher 1
2, Publisher 2
3, Publisher 3
BookAuthor (id, bookId, authorId)
1, 1, 1
2, 1, 2
3, 1, 3
4, 2, 1
5, 3, 2
PublisherBook(id, publisherId, bookId)
1, 1, 1
2, 1, 2
3, 1, 3
4, 2, 1
5, 3, 2
如果我尝试从 PublisherBook 表中获取 Publisher 1 (id=1) 的所有书籍列表,它应该返回总共 3 本书。但是我总共得到了5本书。Book 1(id = 1) 以不同的作者值(1、2、3)重复 3 次,因此 PublisherBook 列表返回
1, 1, 1
1, 1, 1
1, 1, 1
2, 1, 2
3, 1, 3
如果我从 Book 实体中删除 Set,则发布者 1 的 PublisherBook 列表将返回正确的值
1, 1, 1
2, 1, 2
3, 1, 3
有人可以告诉我我做错了什么吗?为长篇道歉。