SQL Joining tables Using Spring JPA - spring

Question

I have some trouble with joining tables using Spring Boot JPA
I need to do this kind of joining:
**book2user — book to user
id INT NOT NULL AUTO_INCREMENT
time DATETIME NOT NULL
type_id INT NOT NULL
book_id INT NOT NULL
user_id INT NOT NULL**
Here are my Entity classes:
#Entity
#Table(name = "user")
public class User {
#Id
#GeneratedValue(strategy = GenerationType.AUTO)
private Integer id;
private String hash;
private Date reg_time;
private Integer balance = 0;
private String name;
// getters and setters
public class Book {
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
private Integer id;
#ManyToOne
#JoinColumn(name = "author_id", referencedColumnName = "id")
private Author author;
#ManyToOne
#JoinColumn(name = "genre_id", referencedColumnName = "id")
private Genre genre;
private String title;
private String slug;
private String description;
private String priceOld;
private String price;
private String image;
private boolean is_bestseller;
private Date pub_date;
// getters and setters
In order to do this kind of joining I should create another entity class ??

Answer 1

Something like this should work:
#Entity
#Table("book2user")
public class Book2User {
#Id
#GeneratedValue(strategy = GenerationType.IDENTITY)
private Integer id;
private LocalDateTime time;
private Integer typeId;
#OneToOne
private Book book;
#OneToOne
#JoinColumn(name = "user_id") //optional, if the name of the table and field matches.
private User user;
}