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基于HTTP协议的网络应用程序

本文主要是介绍基于HTTP协议的网络应用程序,对大家解决编程问题具有一定的参考价值,需要的程序猿们随着小编来一起学习吧!
#ifndef MAINWINDOW_H
#define MAINWINDOW_H

#include <QMainWindow>
#include <QNetworkAccessManager>
#include <QNetworkReply>
#include <QFile>
#include <QDir>
#include <QMessageBox>
#include <QDesktopServices>

namespace Ui {
class MainWindow;
}

class MainWindow : public QMainWindow
{
    Q_OBJECT

public:
    explicit MainWindow(QWidget *parent = nullptr);
    ~MainWindow();
private:
    QNetworkAccessManager networkManager; //网络管理
    QNetworkReply *reply; //网络响应
    QFile *downloadedFile; //下载保存的临时文件
private slots:
    void on_finished();
    void on_readyRead();
    void on_downloadProgress(qint64 bytesRead ,qint64 totalBytes);

    void on_pushButton_2_clicked();

    void on_pushButton_clicked();

private:
    Ui::MainWindow *ui;
};

#endif // MAINWINDOW_H

#include "mainwindow.h"
#include "ui_mainwindow.h"

MainWindow::MainWindow(QWidget *parent) :
    QMainWindow(parent),
    ui(new Ui::MainWindow)
{
    ui->setupUi(this);
    ui->progressBar->setValue(0);
}

MainWindow::~MainWindow()
{
    delete ui;
}

void MainWindow::on_finished()
{
    QFileInfo fileInfo;
    fileInfo.setFile(downloadedFile->fileName());
    downloadedFile->close();
    delete downloadedFile;
    downloadedFile = Q_NULLPTR;
    reply->deleteLater();
    reply = Q_NULLPTR;
    if(ui->checkBox->isChecked())
    {
       QDesktopServices::openUrl(QUrl::fromLocalFile(fileInfo.absoluteFilePath()));
       ui->pushButton->setEnabled(true);
    }
}

void MainWindow::on_readyRead()
{
    downloadedFile->write(reply->readAll());
}

void MainWindow::on_downloadProgress(qint64 bytesRead, qint64 totalBytes)
{
    ui->progressBar->setMaximum(totalBytes);
    ui->progressBar->setValue(bytesRead);
}

void MainWindow::on_pushButton_2_clicked()
{
    //缺省路径
    QString curPath = QDir::currentPath();
    QDir dir(curPath);
    QString sub = "temp";
    dir.mkdir(sub);
    ui->lineEdit_2->setText(curPath+"/"+sub+"/");
}

void MainWindow::on_pushButton_clicked()
{
    //下载
    QString urlSpec =ui->lineEdit->text().trimmed();
    if(urlSpec.isEmpty())
    {
        QMessageBox::information(this,"错误","请指定需要下载的URL");
        return;
    }
    QUrl newurl = QUrl::fromUserInput(urlSpec);
    if(!newurl.isValid())
    {
        QMessageBox::information(this,"错误",QString("无效URL:%1\n错误信息:%2").arg(urlSpec,newurl.errorString()));
        return;
    }
    QString tempDir = ui->lineEdit_2->text().trimmed();
    if(tempDir.isEmpty())
    {
        QMessageBox::information(this,"错误","请指定保存下载文件的路径");
        return;
    }
    QString fullFileName = tempDir +newurl.fileName();
    if(QFile::exists(fullFileName))
    {
        QFile::remove(fullFileName);
    }
    downloadedFile = new QFile(fullFileName);
    if(!downloadedFile->open(QIODevice::WriteOnly))
    {
        QMessageBox::information(this,"错误","临时文件打开错误");
        return;
    }
    ui->pushButton->setEnabled(false);
    reply = networkManager.get(QNetworkRequest(newurl));
    connect(reply,SIGNAL(finished()),this,SLOT(on_finished()));
    connect(reply,SIGNAL(readyRead()),this,SLOT(on_readyRead()));
    connect(reply,SIGNAL(downloadProgress(qint64,qint64)),this,SLOT(on_downloadProgress(qint64,qint64)));
}

 

 


                    
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