使用QNetworkAssessManager下载文件，支持断点续传和超时处理

#include "downloadManager.h" #include <QFile> #include <QDebug> #include <QFileInfo> #include <QDir> #define DOWNLOAD_FILE_SUFFIX "_tmp" #pragma warning(disable:4099) DownLoadManager::DownLoadManager(QObject *parent) : QObject(parent) , m_networkManager(NULL) , m_url(QUrl("")) , m_fileName("") , m_bytesReceived(0) , m_bytesTotal(0) , m_bytesCurrentReceived(0) , m_isStop(true) , m_bytesDown(0) , m_bClickPause(false) { _timeOut = new QTimer(this); connect(_timeOut, SIGNAL(timeout()), this, SLOT(handleTimeOut())); qEvent = new QEventLoop(); m_reply = Q_NULLPTR; } DownLoadManager::~DownLoadManager() {} QString DownLoadManager::getDownloadUrl() { return m_url.toString(); } void DownLoadManager::downloadFile(QString url, QString fileName) { // 防止多次下载，只有在停止标志变量为true时才进行下载; if (m_isStop) { m_qStrUrl = url; m_qStrFilePath = fileName; m_isStop = false; m_bClickPause = false; m_url = QUrl(url); m_fileName = fileName + DOWNLOAD_FILE_SUFFIX;// 将当前文件名设置为临时文件名，下载完成时修改回来; this->removeFileterFiles(m_fileName); //检测下载文件是否存在缓存本地文件，如果有则继续下载 QFileInfo fileInfo(m_fileName); m_bytesCurrentReceived = fileInfo.size(); m_networkManager = new QNetworkAccessManager(this); connect(m_networkManager, SIGNAL(finished(QNetworkReply*)), this, SLOT(replyFinished(QNetworkReply*))); QNetworkRequest request; request.setUrl(m_url); if (this->bSupportBreak(m_url)) { //断点续传需要添加Range请求头 QString strRange = QString("bytes=%1-").arg(m_bytesCurrentReceived); request.setRawHeader("Range", strRange.toLatin1()); } else m_bytesCurrentReceived = 0; if (m_bytesCurrentReceived <= 0) { removeFile(m_fileName); } m_reply = m_networkManager->get(QNetworkRequest(request)); connect(m_reply, SIGNAL(downloadProgress(qint64,qint64)), this, SLOT(onDownloadProgress(qint64, qint64))); connect(m_reply, SIGNAL(readyRead()), this, SLOT(onReadyRead())); connect(m_reply, SIGNAL(finished()), this, SLOT(onFinished())); connect(m_reply, SIGNAL(error(QNetworkReply::NetworkError)), this, SLOT(onError(QNetworkReply::NetworkError))); //设置每5s启动检查时候网络异常 _timeOut->start(5000); if (!qEvent->isRunning()) { qEvent->exec(); } } } void DownLoadManager::onDownloadProgress(qint64 bytesReceived, qint64 bytesTotal) { if (!m_isStop) { m_bytesReceived = bytesReceived; m_bytesTotal = bytesTotal; // 更新下载进度;(加上 m_bytesCurrentReceived 是为了断点续传时之前下载的字节) emit signalDownloadProcess(bytesReceived + m_bytesCurrentReceived, bytesTotal + m_bytesCurrentReceived); } } void DownLoadManager::onReadyRead() { if (m_reply == NULL) return; if (!m_isStop) { QFile file(m_fileName); if (file.open(QIODevice::WriteOnly | QIODevice::Append)) { file.write(m_reply->readAll()); } file.close(); } } void DownLoadManager::onFinished() { m_isStop = true; if (m_reply == NULL) return; QVariant statusCode = m_reply->attribute(QNetworkRequest::HttpStatusCodeAttribute); if (m_reply->error() == QNetworkReply::NoError) { // 重命名临时文件; QFileInfo fileInfo(m_fileName); if (fileInfo.exists()) { int index = m_fileName.lastIndexOf(DOWNLOAD_FILE_SUFFIX); QString realName = m_fileName.left(index); QFile::rename(m_fileName, realName); } qDebug() << "Finished" ; } else { // 有错误输出错误; QString strError = m_reply->errorString(); qDebug() << "__________" + strError; } qEvent->exit(); emit signalReplyFinished(statusCode.toInt()); } void DownLoadManager::onError(QNetworkReply::NetworkError code) { QString strError = m_reply->errorString(); qDebug() << "__________" + strError << code; closeDownload(); emit signalDownloadError(); } void DownLoadManager::handleTimeOut() { if (m_bytesDown != m_bytesReceived) { m_bytesDown = m_bytesReceived; } else if( !m_bClickPause){ //网络断开时停止下载 if (m_reply != NULL) { stopDownload(); m_timeElapsed.start(); } //30分钟循环超时(30分钟再次连接网络可以继续下载) int nElapsed = m_timeElapsed.elapsed(); if (nElapsed >= 1 * 30 * 60 * 1000) { _timeOut->stop(); return; } //检测网络 bool bConnect = this->bSupportBreak(m_qStrUrl); if (bConnect) { _timeOut->stop(); this->downloadFile(m_qStrUrl, m_qStrFilePath); } } } void DownLoadManager::stopWork() { m_isStop = true; if (m_reply != NULL) { disconnect(m_reply, SIGNAL(downloadProgress(qint64, qint64)), this, SLOT(onDownloadProgress(qint64, qint64))); disconnect(m_reply, SIGNAL(readyRead()), this, SLOT(onReadyRead())); disconnect(m_reply, SIGNAL(finished()), this, SLOT(onFinished())); disconnect(m_reply, SIGNAL(error(QNetworkReply::NetworkError)), this, SLOT(onError(QNetworkReply::NetworkError))); m_reply->abort(); m_reply->deleteLater(); m_reply = NULL; } } void DownLoadManager::stopDownload() { if (!m_isStop) { //记录当前已经下载字节数； QFileInfo info(m_fileName); m_bytesCurrentReceived = info.size(); stopWork(); } } void DownLoadManager::reset() { m_bytesCurrentReceived = 0; m_bytesReceived = 0; m_bytesTotal = 0; } void DownLoadManager::removeFile(QString fileName) { // 删除已下载的临时文件; QFileInfo fileInfo(fileName); if (fileInfo.exists()) { QFile::remove(fileName); } } void DownLoadManager::removeFileterFiles(QString fileName) { QString qStrPath = QCoreApplication::applicationDirPath() + "/Download/"; QDir dir(qStrPath); //设置筛选条件 QStringList filterLst; filterLst << "*.exe_tmp"; dir.setNameFilters(filterLst); QFileInfoList fileInfoLst = dir.entryInfoList(filterLst); for (int i = 0; i < fileInfoLst.count(); i++) { QString fileComplete =fileInfoLst[i].filePath(); if (fileComplete.compare(fileName) !=0){ removeFile(fileComplete); } } } void DownLoadManager::closeDownload() { stopWork(); reset(); removeFile(m_fileName); } void DownLoadManager::replyFinished(QNetworkReply*) /* download finished */ { } bool DownLoadManager::bSupportBreak(const QUrl &url) { QNetworkAccessManager manager; QEventLoop loop; QTimer timer; QNetworkRequest request; request.setUrl(url); request.setRawHeader("Range","bytes=0-9"); //发出请求，获取文件地址的头部信息; QNetworkReply *reply = manager.get(request); if (!reply) return false; connect(reply, SIGNAL(finished()), &loop, SLOT(quit())); connect(&timer, SIGNAL(timeout()), &loop, SLOT(quit())); timer.start(2000); loop.exec(QEventLoop::ExcludeUserInputEvents); if (reply->error() != QNetworkReply::NoError) { // 请求发生错误; qDebug() << reply->errorString(); return false; } else if (!timer.isActive()) { // 请求超时超时,未获取到文件信息; qDebug() << "Request Timeout"; return false; } timer.stop(); QByteArray range = reply->rawHeader("Content-Range"); if (!QString::fromLocal8Bit(range).isEmpty()) return true; return false; }