qt 5.15.2 网络文件下载功能
#include <QCoreApplication>
#include <iostream>
#include <QFile>
#include <QTextStream>
//
#include <QtCore>
#include <QtNetwork>
#include <QNetworkAccessManager>
#include <QNetworkReply>
#include <QUrl>
#include <QDir>
//
#include <QStringList>
#include "downloadmanager.h"
//
int printf(QString line)
{
std::cout<<line.toStdString()<<std::endl;
}
int printf(int line)
{
std::cout<<line<<std::endl;
}
int main(int argc, char *argv[])
{
QCoreApplication a(argc, argv);
std::cout<<"Hello World! hsg77"<<std::endl;
QString toDirPath="C:\\data\\obj\\test";
DownloadManager manager;
manager.setOutDir(toDirPath);
//manager.append(arguments);
//打开csv文件
QFile file("E:\\QtProject\\objDownloadTest\\GridIdx_OBJ.csv");
std::cout<<file.fileName().toStdString()<<std::endl;
if(file.exists())
{
if(file.open(QIODevice::ReadOnly))
{
QTextStream in(&file);
//std::cout<<"file state="<<in.atEnd()<<std::endl;
while(!in.atEnd())
{
QString line=in.readLine();
QStringList fds=line.split(" ");
//std::cout<<line.toStdString()<<std::endl;
//printf(fds.length());
//处理每一行的数据
QString fileUrl=fds.at(13);
printf("readydown="+fileUrl);
if(fileUrl!="FILE_URL")
{
//下载文件 fileUrl
QUrl url(fileUrl);
manager.append(url);
}
}
//
}
}
//
file.close();
std::cout<<"csv file closed"<<std::endl;
//开始下载开始
QObject::connect(&manager,&DownloadManager::finished,&a,&QCoreApplication::quit);
return a.exec();
}
定义：下载管理类
DownloadManager.h
#ifndef DOWNLOADMANAGER_H
#define DOWNLOADMANAGER_H
#include <QtNetwork>
#include <QtCore>
#include "textprogressbar.h"
class DownloadManager: public QObject
{
Q_OBJECT
public:
explicit DownloadManager(QObject *parent = nullptr);
void append(const QUrl &url);
void append(const QStringList &urls);
static QString saveFileName(const QUrl &url,const QString outDir);
void setOutDir(const QString outDir);
signals:
void finished();
private slots:
void startNextDownload();
void downloadProgress(qint64 bytesReceived, qint64 bytesTotal);
void downloadFinished();
void downloadReadyRead();
private:
bool isHttpRedirect() const;
void reportRedirect();
QNetworkAccessManager manager;
QQueue<QUrl> downloadQueue;
QNetworkReply *currentDownload = nullptr;
QFile output;
QElapsedTimer downloadTimer;
TextProgressBar progressBar;
int downloadedCount = 0;
int totalCount = 0;
QString outDir="";
};
#endif // DOWNLOADMANAGER_H
DownloadManager.cpp
#include "downloadmanager.h"
#include <QTextStream>
#include <cstdio>
using namespace std;
DownloadManager::DownloadManager(QObject *parent)
: QObject(parent)
{
}
void DownloadManager::append(const QStringList &urls)
{
for (const QString &urlAsString : urls)
append(QUrl::fromEncoded(urlAsString.toLocal8Bit()));
if (downloadQueue.isEmpty())
QTimer::singleShot(0, this, &DownloadManager::finished);
}
void DownloadManager::append(const QUrl &url)
{
if (downloadQueue.isEmpty())
QTimer::singleShot(0, this, &DownloadManager::startNextDownload);
downloadQueue.enqueue(url);
++totalCount;
}
QString DownloadManager::saveFileName(const QUrl &url,const QString outDir)
{
QString path = url.path();
QString basename = QFileInfo(path).fileName();
QString newFilePath=outDir+"\\"+basename;
return newFilePath;
//
if (basename.isEmpty())
basename = "download";
if (QFile::exists(basename)) {
// already exists, don't overwrite
int i = 0;
basename += '.';
while (QFile::exists(basename + QString::number(i)))
++i;
basename += QString::number(i);
}
return basename;
}
void DownloadManager::setOutDir(const QString outDir)
{
this->outDir=outDir;
}
void DownloadManager::startNextDownload()
{
if (downloadQueue.isEmpty()) {
printf("%d/%d files downloaded successfully\n", downloadedCount, totalCount);
emit finished();
return;
}
QUrl url = downloadQueue.dequeue();
QString filename = saveFileName(url,this->outDir);
output.setFileName(filename);
if (!output.open(QIODevice::WriteOnly)) {
fprintf(stderr, "Problem opening save file '%s' for download '%s': %s\n",
qPrintable(filename), url.toEncoded().constData(),
qPrintable(output.errorString()));
startNextDownload();
return; // skip this download
}
QNetworkRequest request(url);
currentDownload = manager.get(request);
connect(currentDownload, &QNetworkReply::downloadProgress,
this, &DownloadManager::downloadProgress);
connect(currentDownload, &QNetworkReply::finished,
this, &DownloadManager::downloadFinished);
connect(currentDownload, &QNetworkReply::readyRead,
this, &DownloadManager::downloadReadyRead);
// prepare the output
printf("Downloading %s...\n", url.toEncoded().constData());
downloadTimer.start();
}
void DownloadManager::downloadProgress(qint64 bytesReceived, qint64 bytesTotal)
{
progressBar.setStatus(bytesReceived, bytesTotal);
// calculate the download speed
double speed = bytesReceived * 1000.0 / downloadTimer.elapsed();
QString unit;
if (speed < 1024) {
unit = "bytes/sec";
} else if (speed < 1024*1024) {
speed /= 1024;
unit = "kB/s";
} else {
speed /= 1024*1024;
unit = "MB/s";
}
progressBar.setMessage(QString::fromLatin1("%1 %2")
.arg(speed, 3, 'f', 1).arg(unit));
progressBar.update();
}
void DownloadManager::downloadFinished()
{
progressBar.clear();
output.close();
if (currentDownload->error()) {
// download failed
fprintf(stderr, "Failed: %s\n", qPrintable(currentDownload->errorString()));
output.remove();
} else {
// let's check if it was actually a redirect
if (isHttpRedirect()) {
reportRedirect();
output.remove();
} else {
printf("Succeeded.\n");
++downloadedCount;
}
}
currentDownload->deleteLater();
startNextDownload();
}
void DownloadManager::downloadReadyRead()
{
output.write(currentDownload->readAll());
}
bool DownloadManager::isHttpRedirect() const
{
int statusCode = currentDownload->attribute(QNetworkRequest::HttpStatusCodeAttribute).toInt();
return statusCode == 301 || statusCode == 302 || statusCode == 303
|| statusCode == 305 || statusCode == 307 || statusCode == 308;
}
void DownloadManager::reportRedirect()
{
int statusCode = currentDownload->attribute(QNetworkRequest::HttpStatusCodeAttribute).toInt();
QUrl requestUrl = currentDownload->request().url();
QTextStream(stderr) << "Request: " << requestUrl.toDisplayString()
<< " was redirected with code: " << statusCode
<< '\n';
QVariant target = currentDownload->attribute(QNetworkRequest::RedirectionTargetAttribute);
if (!target.isValid())
return;
QUrl redirectUrl = target.toUrl();
if (redirectUrl.isRelative())
redirectUrl = requestUrl.resolved(redirectUrl);
QTextStream(stderr) << "Redirected to: " << redirectUrl.toDisplayString()
<< '\n';
}
定义进度条类
TextProgressBar.h
#ifndef TEXTPROGRESSBAR_H
#define TEXTPROGRESSBAR_H
#include <QString>
class TextProgressBar
{
public:
void clear();
void update();
void setMessage(const QString &message);
void setStatus(qint64 value, qint64 maximum);
private:
QString message;
qint64 value = 0;
qint64 maximum = -1;
int iteration = 0;
};
#endif // TEXTPROGRESSBAR_H
TextProgressBar.cpp
#include "textprogressbar.h"
#include <QByteArray>
#include <cstdio>
using namespace std;
void TextProgressBar::clear()
{
printf("\n");
fflush(stdout);
value = 0;
maximum = -1;
iteration = 0;
}
void TextProgressBar::update()
{
++iteration;
if (maximum > 0) {
// we know the maximum
// draw a progress bar
int percent = value * 100 / maximum;
int hashes = percent / 2;
QByteArray progressbar(hashes, '#');
if (percent % 2)
progressbar += '>';
printf("\r[%-50s] %3d%% %s ",
progressbar.constData(),
percent,
qPrintable(message));
} else {
// we don't know the maximum, so we can't draw a progress bar
int center = (iteration % 48) + 1; // 50 spaces, minus 2
QByteArray before(qMax(center - 2, 0), ' ');
QByteArray after(qMin(center + 2, 50), ' ');
printf("\r[%s###%s] %s ",
before.constData(), after.constData(), qPrintable(message));
}
}
void TextProgressBar::setMessage(const QString &m)
{
message = m;
}
void TextProgressBar::setStatus(qint64 val, qint64 max)
{
value = val;
maximum = max;
}
–the—end—
本blog地址：http://blog.csdn.net/hsg77