JavaWeb用户信息管理系统-创建登录业的业务层

public interface UserLoginService {
     Users userLogin(String username,String userpwd);
}

/**
 * 用户登录业务
 * */
public class UserLoginServiceImpl implements UserLoginService {
  /**
   * 用户登录
   * */
    @Override
    public Users userLogin(String username, String userpwd) {
        UserLoginDao userLoginDao=new UserLoginDaoImpl() ;
        Users users = userLoginDao.selectUsersByUserPwd(username, userpwd);
        if(users==null){
throw  new UserNotFoundException("用户名货密码有误！");
        }
        return null;
    }
}

/**
 * 用户登录状态的自定义异常
 * */
public class UserNotFoundException extends RuntimeException {
    public UserNotFoundException() {
    }
    public UserNotFoundException(String message) {
        super(message);
    }
    public UserNotFoundException(String message, Throwable cause) {
        super(message, cause);
    }
}