public void exec() throws IOException {
        int mode = NumUtil.readInteger(In);
        boolean ret = false;
        switch (mode) {
        case HadukiCode.LOGIN_ACCEPT:
            execLogin();
            break;
        case HadukiCode.LOGOFF_ACCEPT:
            execLogoff();
            break;
        default:
            throw new IOException("NGXgُłB@UserRequest#exec");
        }
    }