QNetworkProxy* proxy = new QNetworkProxy();
    proxy->setHostName("127.0.0.1");
    proxy->setPort(8580);
    proxy->setType(QNetworkProxy::HttpProxy);
    QNetworkProxy::setApplicationProxy(*proxy);
    QNetworkRequest req;
    QUrl url1= QUrl("http://www.youtube.com"); //此处改成
http://www.google.com 却可以得到内容
    req.setUrl(url1);
    req.setRawHeader("User-Agent", "Mozilla/5.0");
    req.setRawHeader("Referer", url1.toString().toAscii());
        //req.setRawHeader("Accept-Charset", "ISO-8859-1,utf-8;q=0.7,*;q=0.7");
        //req.setRawHeader("Accept", "text/xml,application/xml,application/xhtml+xml,text/html;q=0.9,text/plain;q=0.8,image/png,*/*;q=0.5");
        //req.setRawHeader("Accept-Language", "en-us,en;q=0.5");
    QNetworkAccessManager* manager = new QNetworkAccessManager(this);
    manager->setCookieJar(new QNetworkCookieJar());
    //manager->setProxy(*proxy);
    QNetworkReply* reply = manager->get(req);
    //http.get("/watch?v=YNzFN6EFfrA&feature=rec-exp_fresh+div-1r-2-HM");
    //qDebug() << url.path();
    connect ( manager,SIGNAL(finished(QNetworkReply*)),this,SLOT(slotFinished(QNetworkReply*)));