问Spring Controller -将JSON属性映射到外键实体

EN

@RestController
@RequestMapping("/users")
public class UserController {
    // code
    @PostMapping("/sign-up")
    public void signUp(@RequestBody User user) {
        //code
    }
}

@Entity
public class User {
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    @Column(name = "user_id")
    private long id;

    @ManyToOne
    @JoinColumn(name = "language_id")
    private Language language;

    // others
    public User() {
    }
}

{
    "foreName" : "bla",
    "sureName" : "blo",
    "language" : "1"
}