How to set a foreign key via a controller in java j2ee?

Question

I have two tables clients and contact :

public class Contacts implements Serializable{

    @Id
    @GeneratedValue
    private Long idContacts;


    private String nomContacts;
    private String prenomContacts;
    private String telephone;
    private String autreTelephone;
    private String fax;
    private String email;
    private int deleted = 0;


    @ManyToOne(cascade = CascadeType.PERSIST)
    @JoinColumn(name = "idClient")
    private Client client;
}

and I declared an instance of Contact:

Contacts contact = new Contacts() 

How can I set the foreign key of Contact manually I tried : contact.getClient().setIdClient(1) and it did not work.

Answer 1

A major purpose of JPA is to avoid manually fiddling with relationship keys; instead, just use regular Java references. For what you're trying to do:

Client clientOne = clients.find(1L); // or get the client some other way
contact.setClient(clientOne);

Note that Spring Data (in addition to autoimplemented repositories) provides a converter, so that if you have a method argument for your controller that refers to an existing object's ID, you can pass the object itself instead of looking up manually:

@GetMapping("/clients/{id}")
public Client getClient(@PathVariable("id") Client client) {
    return client;
}