QT实现HTTP请求回应程序

#include "widget.h" #include "ui_widget.h" Widget::Widget(QWidget *parent) : QWidget(parent), ui(new Ui::Widget) { ui->setupUi(this); manager = new QNetworkAccessManager(this); ui->progressBar->hide(); } Widget::~Widget() { delete ui; } void Widget::on_pushButton_clicked() //下载按钮 { url = ui->lineEdit->text(); //获取在界面中输入的url地址，如http://zz.onlinedown.net/down/laolafangkuaijin.rar QFileInfo info(url.path()); QString fileName(info.fileName()); //获取文件名 if(fileName.isEmpty()) fileName = "index.html"; //如果文件名为空，则使用“index.html”， //例如使用“http://www.yafeilinux.com”时，文件名就为空 file = new QFile(fileName); if(!file->open(QIODevice::WriteOnly)) { //如果打开文件失败，则删除file，并使file指针为0，然后返回 qDebug() << "file open error"; delete file; file = 0; return; } startRequest(url); //进行链接请求 ui->progressBar->setValue(0); //进度条的值设为0 ui->progressBar->show(); //显示进度条 } void Widget::startRequest(QUrl url) //链接请求 { reply = manager->get(QNetworkRequest(url)); //下面关联信号和槽 connect(reply,SIGNAL(finished()),this,SLOT(httpFinished())); //下载完成后 connect(reply,SIGNAL(readyRead()),this,SLOT(httpReadyRead())); //有可用数据时 connect(reply,SIGNAL(downloadProgress(qint64,qint64)), this,SLOT(updateDataReadProgress(qint64,qint64))); //更新进度条 } void Widget::httpReadyRead() //有可用数据 { if (file) file->write(reply->readAll()); //如果文件存在，则写入文件 } void Widget::updateDataReadProgress(qint64 bytesRead, qint64 totalBytes) { ui->progressBar->setMaximum(totalBytes); //最大值 ui->progressBar->setValue(bytesRead); //当前值 } void Widget::httpFinished() //完成下载 { ui->progressBar->hide(); file->flush(); file->close(); reply->deleteLater(); reply = 0; delete file; file = 0; }