9.sevice层

接口

public interface UserService {
    List<User> getUserList();

    User getUser(int id);
}

接口实现类

@Service("userService")
public class UserServiceImpl implements UserService{
    @Autowired
    private UserDao userDao;

    public List<User> getUserList() {
        List<User> userList = userDao.getUserList();
        return userList;
    }

    public User getUser(int id) {
        User user = userDao.getUser(id);
        return user;
    }
}