QT HTTP断点续传下载(非多线程)

#include <QtCore> #include <QtNetwork> #include <iostream> #include "stdio.h" #include "stdlib.h" #include "time.h" #include "downloadObject.h" downloadObject::downloadObject(QObject *parent) : QObject(parent) { http = new QHttp(this); //resp = new QHttpResponseHeader(); connect(http, SIGNAL(done(bool)), this, SLOT(httpDone(bool))); connect(http, SIGNAL(dataReadProgress(int,int)), this, SLOT(updateProgress(int,int))); } bool downloadObject::getFile(const QUrl &url,const qint64 totalSizet) { if (!url.isValid()) { std::cerr << "Error: Invalid URL" << std::endl; return false; } if (url.scheme() != "http") { std::cerr << "Error: URL must start with 'http:'" << std::endl; return false; } if (url.path().isEmpty()) { std::cerr << "Error: URL has no path" << std::endl; return false; } localFileName = QFileInfo(url.path()).fileName(); if (localFileName.isEmpty()) localFileName = "httpget.out"; file.setFileName(localFileName); qint64 dwSize = 0; totalSize = totalSizet; // if(file.exists())//这边我取了个非 // { dwSize = file.size(); beforeSize = dwSize; if (!file.open(QIODevice::Append)) { std::cerr << "Error: Cannot write file " << qPrintable(file.fileName()) << ": " << qPrintable(file.errorString()) << std::endl; return false; } QHttp::ConnectionMode mode = url.scheme().toLower() == "https" ? QHttp::ConnectionModeHttps : QHttp::ConnectionModeHttp; http->setHost(url.host(), mode, url.port() == -1 ? 0 : url.port()); // qint64 totalSize = http->bytesAvailable(); /*http->setHost(url.host(), ,url.port(80));*/ QHttpRequestHeader *header = new QHttpRequestHeader("GET", url.path()); header->setValue("Connection", "Keep-Alive"); QString str = "bytes="; QString strTemp = QString("%1").arg(dwSize); str+=strTemp; // dwSize += 100; if (dwSize>totalSize) { dwSize = totalSize; } str+="-"; strTemp = QString("%1").arg(totalSize); str += strTemp; header->setValue("Range", str); strTemp = url.host()+":80"; header->setValue("Host", strTemp); http->request(*header, 0, &file); http->close(); return true; // } } void downloadObject::abort() { http->abort(); file.close(); //return; } void downloadObject::httpDone(bool error) { if (error) { QString sre = http->errorString(); std::cerr << "Error: " << qPrintable(http->errorString()) << std::endl; } else { std::cerr << "File downloaded as " << qPrintable(file.fileName()) << std::endl; } file.close(); emit downloadDone(); } void downloadObject::updateProgress(int current, int all) { if(current<0) { current = 0; } if(beforeSize<0) { beforeSize = 0; } current = beforeSize+current; emit updateProgressbar(current, totalSize); } qint64 downloadObject::fileGetSize(const QUrl &url) { //QString strUrl = ui->lineEditURL->text(); //QUrl url = QUrl(strUrl); QNetworkAccessManager manager; QEventLoop loop; //发出请求，获取目标地址的头部信息 QNetworkReply *reply = manager.head(QNetworkRequest(url)); QObject::connect(reply, SIGNAL(finished()), &loop, SLOT(quit()), Qt::DirectConnection); loop.exec(); QVariant var = reply->header(QNetworkRequest::ContentLengthHeader); delete reply; qint64 size = var.toLongLong(); //ui->lineEditGetSize->setText(QString::number(size)); return size; }