如何在spring boot rest & postman中使用表单数据保存用户？

@Entity
@Table(name = "users")
public class User {
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Long id;

    @Column(nullable = false)
    private String username;

    @Column(nullable = false)
    private String password;

    @Column(nullable = false)
    private String email;

    // 省略构造函数、getter和setter方法
}

@RestController
@RequestMapping("/users")
public class UserController {
    @Autowired
    private UserRepository userRepository;

    @PostMapping
    public User createUser(@RequestBody User user) {
        return userRepository.save(user);
    }
}

public interface UserRepository extends JpaRepository<User, Long> {
}

{
    "username": "john",
    "password": "password123",
    "email": "john@example.com"
}