使用QHttp下载网络文件的简单例子

来源：互联网发布：JSON键值对转java对象编辑：程序博客网时间：2024/05/13 13:20

场景:

1 可用作软件更新。

2 文件下载服务器

注意:

1 *.pro 添加 QT += network

2 VS下，链接器---附加依赖项--输入---添加 QtNetworkd4.lib或QtNetwork4.lib，根据debug和release选择。

3 exe目录拷贝QtNetworkd4.dll或QtNetwork4.dll,根据debug和release选择。

4 网络环境是在非代理下使用，否则程序需要设置代理,使用QNetworkProxy类

1 http_get.h

#ifndef HTTP_GET_H#define HTTP_GET_H#include <QObject>#include <QtCore>#include <QtGui>#include <QtNetwork/QtNetwork>#include <QtNetwork/QHttp>#include <iostream>#include <stdio.h>#include <QUrl>#include <QWidget>#include <QFile>#include <QTextStream>#include <QNetworkAccessManager>#include <QTextCodec>using namespace std;class HttpGet : public QObject{    Q_OBJECTpublic:    explicit HttpGet(QObject *parent = 0);    bool getFile(const QUrl &url);signals:    void done();public slots:    void httpDone(bool error); private:    QHttp http;    QFile file;};#endif // HTTP_GET_H

2 http_get.cpp

#include "http_get.h"HttpGet::HttpGet(QObject *parent) :QObject(parent){    connect(&http,SIGNAL(done(bool)),this,SLOT(httpDone(bool)));}bool HttpGet::getFile(const QUrl &url){    if(!url.isValid())    {         std::cerr<<"error: Invalid URL!" <<endl;         return false;    }    if(url.scheme() != "http")    {        std::cerr<<"error: URL must start with 'http:'" <<endl;        return false;    }    if(url.path().isEmpty())    {        std::cerr<<"error: URL has no path!" <<endl;        return false;    }    QFileInfo fileInfo(url.path());    QString localFileName = fileInfo.fileName();    if(localFileName.isEmpty())    {        localFileName = "http.out";    }    file.setFileName(localFileName);    if(!file.open((QIODevice::WriteOnly)))    {        std::cerr<<"error: Cannot write file" <<":"<<qPrintable(file.fileName())<<": "<<qPrintable(file.errorString())<<endl;        return false;    }    http.setHost(url.host(),url.port(80));// 服务器端口    http.get(url.path(),&file);    http.close();    return true;}void HttpGet::httpDone(bool error){    if(error)    {        std::cerr<<"error:"<<qPrintable(http.errorString())<<endl;    }    else    {        std::cerr<<"file download as "<<qPrintable(file.fileName())<<endl;    }    file.close();    emit done();<span style="color:#cc0000;">// 链接成功才会自动下载</span>}

3 main.cpp

#include <QtGui/QApplication>#include "http_get.h"int main(int argc, char *argv[]){    QApplication a(argc, argv);    MainWindow w;    w.show(); HttpGet getter; QString str("http://www.istonsoft.com/win-update.xml"); QUrl url(str);     getter.getFile(url);      return a.exec();}

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