Add extra custom column to auto mapped Table in Spring JPA ManyToMany - spring

Question

#Getter #Setter #NoArgsConstructor #AllArgsConstructor
#Table(name = "my_users")
public class MyUsers {
#Id
#GeneratedValue(strategy = GenerationType.AUTO)
#Column(nullable = false)
private Long id;
#Column(nullable = false, unique = true)
private String userName;
private String password;
#ManyToMany
private List<MyUsers> connections;
}
This is my MyUsers Model Class. I am using Hibernate and MySQL.
#ManyToMany
private List<MyUsers> connections;
This ManyToMany relationship is automatically creating the table 'my_users_connections' with 'my_users_id' and 'connections_id' colums. How can I add extra columns to this auto mapped table?

Answer 1

It's not ideal solution...
#Getter
#Setter
#NoArgsConstructor
#AllArgsConstructor
#Entity
#Table(name = "my_users")
public class MyUsers implements Serializable {
#Id
#GeneratedValue(strategy = GenerationType.AUTO)
#Column(nullable = false)
private Long myUsersId;
#Column(nullable = false, unique = false)
private String userName;
private String password;
#ManyToMany(cascade = CascadeType.ALL)
#JoinTable(name = "my_users_connections",
joinColumns = { #JoinColumn(name = "my_users_id") },
inverseJoinColumns = { #JoinColumn(name = "connections_id") })
private List<MyUsers> connections;
}
Create embedded id MyUsersConnectionsPK:
#Data
#Embeddable
public class MyUsersConnectionsPK implements Serializable {
#Column(name = "my_users_id")
private Long myUsersId;
#Column(name = "connections_id")
private Long connectionsId;
}
Create MyUsersConnections, which represent ManyToMany
#Data
#Entity
#Table(name = "my_users_connections")
public class MyUsersConnections implements Serializable {
#EmbeddedId
private MyUsersConnectionsPK id;
#ManyToOne
#MapsId("my_users_id")
#JoinColumn(name = "my_users_id")
private MyUsers myUsersId;
#ManyToOne
#MapsId("connections_id")
#JoinColumn(name = "connections_id")
private MyUsers connectionsId;
#Column(name = "extra_column")
private String extraColumn;
}
Create JPA repository
#Repository
public interface MyUsersConnectionsRepository extends JpaRepository<MyUsersConnections, MyUsersConnectionsPK> {
List<MyUsersConnections> findMyUsersConnectionsByMyUsersIdMyUsersId(Long id);
}
And simple sample for using:
#Service
public class Test {
#Autowired
private MyUsersConnectionsRepository myUsersConnectionsRepository;
#Autowired
private MyUsersRepository myUsersRepository;
public void test() {
MyUsers myUsers = new MyUsers();
myUsers.setUserName("user name");
myUsers.setPassword("password");
MyUsers myUsers2 = new MyUsers();
myUsers2.setUserName("user name 2");
myUsers2.setPassword("password 2");
myUsers.setConnections(Collections.singletonList(myUsers2));
myUsers = myUsersRepository.saveAndFlush(myUsers);
List<MyUsersConnections> myUsersConnections = myUsersConnectionsRepository.findMyUsersConnectionsByMyUsersIdMyUsersId(myUsers.getMyUsersId());
MyUsersConnections item = myUsersConnections.get(0);
item.setExtraColumn("Extra column");
myUsersConnectionsRepository.saveAndFlush(item);
}
}