#include <QtCore/QCoreApplication>

#include <QNetworkAccessManager>
#include <QNetworkReply>
#include <QDebug>
#include <QFile>
#include <QThread>


#define USAGE QT_TRANSLATE_NOOP("threadDownload::main", "usage: %s <link> <file name>")

class ThreadHttpDownload : public QThread
{
    Q_OBJECT

    public:
        ThreadHttpDownload(QObject *parent,QString link);

        QNetworkReply *reply;
        QFile file;

        QString link;
        void run();

    private:

    private slots:
        void readyRead();
        void replyFinished(QNetworkReply*);
};

ThreadHttpDownload::ThreadHttpDownload(QObject *parent,QString _link)
        :QThread(parent)
{
     link = _link;
}

void ThreadHttpDownload::run()
{

    file.setFileName("download.file");
    file.open(QIODevice::WriteOnly);

     QNetworkRequest request;  // Формируем запрос
     request.setUrl(QUrl(link));


     QNetworkAccessManager manager;
     manager.moveToThread(this);

     reply = manager.get(request); //Отправляем запрос
     reply->moveToThread(this);

     connect(&manager, SIGNAL(finished(QNetworkReply*)),
         this, SLOT(replyFinished(QNetworkReply*)));
     connect(reply,SIGNAL(readyRead()),this,SLOT(readyRead()));

     exec();
}


void ThreadHttpDownload::readyRead()
{
        qDebug() << reply->size();
        file.write(reply->readAll());
}

void ThreadHttpDownload::replyFinished(QNetworkReply *reply)
{
    if (reply->error())
    {
        qDebug() << "error download" << reply->errorString();
        QCoreApplication::quit();
    }else
    {
        qDebug() << "download complete";
        file.close();
        QCoreApplication::quit();
    }
}

int main(int argc, char *argv[])
{
    if (argc < 2)
    {
        qDebug(USAGE, argv[0]);
        return 0;
    }

    QCoreApplication a(argc, argv);

        ThreadHttpDownload *th = new ThreadHttpDownload(0,argv[1]);
        th->start();

    return a.exec();
}

#include <main.moc>

C:\threadDownload4\debug>threadDownload5.exe http://127.0.0.1/AdobePhotoshopCS4.
rar
32768
32768
0
32768
32768
ASSERT: "d->ref == 1" in file tools\qlistdata.cpp, line 123

This application has requested the Runtime to terminate it in an unusual way.
Please contact the application's support team for more information.