(Sprint Boot)如何在jpa中使用mysql的'IF‘

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

    private String name;

    private Integer age;

    // 省略构造方法、getter和setter
}

@Repository
public interface UserRepository extends JpaRepository<User, Long> {
    @Query(value = "SELECT u FROM User u WHERE IF(:age IS NOT NULL, u.age = :age, TRUE)")
    List<User> findByAge(@Param("age") Integer age);
}

@Service
public class UserService {
    @Autowired
    private UserRepository userRepository;

    public List<User> getUsersByAge(Integer age) {
        return userRepository.findByAge(age);
    }
}