spring 注入问题 获取值为null,是什么原因？

public interface UserService {
void add(User user);
}
@Service
public class UserServiceImpl implements UserService {
@Resource
private UserDao userDao;
public void add(User user){
    userDao.add(user);
}
}
@Controller
@Scope("prototype")
public class TestBean {
@Resource()
private UserService userService ;
@Test
public void testHibernate() throws Exception {
    System.out.println("==================");
    System.out.println(userService);
    System.out.println("==================");
}
}

这样打印出null，没搞明白是哪里写错了吗？
applicationContext.xml就配了一个

/context:component-scan