QT网络编程http之url下载

创建一个mainwind类Application

mainwind.h

#ifndef MAINWINDOW_H

#define MAINWINDOW_H

#include <QMainWindow>

#include <QtNetwork>

namespace Ui {

class MainWindow;

class MainWindow : public QMainWindow

    Q_OBJECT

public:

    explicit MainWindow(QWidget *parent = 0);

    ~MainWindow();

    void startRequest(QUrl url);//请求链接

private slots:

    void on_pushButton_clicked();//下载按钮的单击事件槽函数

    void httpFinished();//完成下载后的处理

    void httpReadyRead();//接收到数据时的处理

    void updateDataReadProgress(qint64, qint64); //更新进度条

private:

    Ui::MainWindow *ui;

    QNetworkAccessManager *manager;

    QNetworkReply *reply;

    QUrl url;   //存储网络地址

    QFile *file;  //文件指针

};

#endif // MAINWINDOW_H

在mainwind.cpp

#include "mainwindow.h"

#include "ui_mainwindow.h"

#include <QTextCodec>

#include <QDebug>

MainWindow::MainWindow(QWidget *parent) :

    QMainWindow(parent),

    ui(new Ui::MainWindow)

    ui->setupUi(this);

    manager=new QNetworkAccessManager(this);

    ui->progressBar->hide();

MainWindow::~MainWindow()

    delete ui;

void MainWindow::startRequest(QUrl url)

       reply = manager->get(QNetworkRequest(url));//发起请求

       connect(reply, SIGNAL(readyRead()), this, SLOT(httpReadyRead()));

        connect(reply, SIGNAL(downloadProgress(qint64, qint64)),

         this, SLOT(updateDataReadProgress(qint64, qint64)));

       connect(reply, SIGNAL(finished()), this, SLOT(httpFinished()));

//判断是否创建了文件，如果是则读取返回的所有数据，然后写入文件。

//该文件是在下载按钮单击信号槽中创建并打开的。

void MainWindow::updateDataReadProgress(qint64 bytesRead, qint64 totalBytes)

    ui->progressBar->setMaximum(totalBytes);

    ui->progressBar->setValue(bytesRead);

//当下载后，重新隐藏进度条，然后删除reply和服了对象。

void MainWindow::on_pushButton_clicked()

        url = ui->lineEdit->text();//从lineEdit中获取信息

        QFileInfo info(url.path());//从url中获取path信息

        QString fileName(info.fileName());//从url中获取filename

        if (fileName.isEmpty()) fileName = "index.html";//判断文件名是否存在，如果为空将filename设置为默认页

        file = new QFile(fileName);//根据url中的文件名创建url对像

        if(!file->open(QIODevice::WriteOnly))

            qDebug() << "file open error";

            delete file;

            file = 0;

            return;

        qDebug()<<"url"<<url;

        startRequest(url);//开始请求url

        ui->progressBar->setValue(0);//设置进度条只为0

        ui->progressBar->show();//显示进度条

void MainWindow::httpFinished()

        ui->progressBar->hide();//数据传输完成隐藏进度条

        file->flush();//刷新数据缓冲区

        file->close();//关闭文件描述符

        reply->deleteLater();//释放relay对象

        reply = 0;

        delete file;

        file = 0;

void MainWindow::httpReadyRead()

    if (file) file->write(reply->readAll());

执行编译运行后可下载url链接http://p4.so.qhmsg.com/t010d8cda7193fa4099.jpg如下为图片下载链接 QT网络编程http之url下载运行效果

下载结果 QT网络编程http之url下载

快获取捏的妹子吧（@——@）

QT网络编程http之url下载