Qt学习笔记网络(一)

Qt5 移除了QHttp是因为功能重复 用QNetworkAccessManager完全能搞定

新建一个控制台应用程序

看一下QNetworkAccessManager的帮助文档

需要添加Qt + =network

新建一个类

.h文件

#ifndef DOWNPAGES_H

#define DOWNPAGES_H

#include<QNetworkAccessManager>

#include <QObject>



class DownPages : public QObject

{

    Q_OBJECT

public:

    explicit DownPages(QObject *parent = 0);

    void Do_Download();

signals:



public slots:

void replyFinished(QNetworkReply*);

private :

    QNetworkAccessManager *manager;

};



#endif // DOWNPAGES_H

我们声明了一个 QNetworkAccesManager

在.cpp里我们把它初始化并把它的finshed信号关联槽

并判断状态是如果 是200也就是请求正常状态把页面输出 

.cpp文件

 

#include "downpages.h"

#include <QNetworkRequest>

#include<QNetworkReply>

#include<QDebug>

#include<QTextCodec>

DownPages::DownPages(QObject *parent) :

    QObject(parent)

{

    manager = new QNetworkAccessManager(this);

    connect(manager, SIGNAL(finished(QNetworkReply*)),

            this, SLOT(replyFinished(QNetworkReply*)));



    QUrl url;

    //url.setUrl("http://www.cnblogs.com/a/b");

    //url.setUrl("http://www.baidu.com/");

    url.setUrl("http://www.sibaieteco.com/");

    //url.setUrl("www.abaibduc.com");

    QNetworkRequest request(url);



    manager->get(request);

}



void DownPages::Do_Download()

{



}

/*

 * 请求完成

 *

 *

 */

void DownPages::replyFinished(QNetworkReply * reply)

{

    //查看是否有错误

    switch(reply->error())

    {

    //如果没有错误把页面输出

    case QNetworkReply::NoError:

        qDebug()<<"no error";



    {

        QTextCodec * cod=QTextCodec::codecForName("utf-8");

        QString str=cod->toUnicode(reply->readAll());

        qDebug()<<str;

    }

        break;

    case QNetworkReply::ContentNotFoundError:

    {

        QUrl failedUrl;

        failedUrl = reply->request().url();

        int httpStatus = reply->attribute(

                    QNetworkRequest::HttpStatusCodeAttribute).toInt();

        QString reason = reply->attribute( QNetworkRequest::HttpReasonPhraseAttribute ).toString();

        qDebug()<<"url"<<failedUrl <<httpStatus<<"   "<<reason;

    }

        break;

    default:

    {

        qDebug()<<"Have error"<<reply->errorString()<<" error "<<reply->error();

    }

    }

    qDebug()<<"finished";

}

再在这个基础上添加一个下载功能

.h文件

#ifndef DOWNPAGES_H

#define DOWNPAGES_H

#include<QNetworkAccessManager>

#include <QObject>

#include <QFile>

class QNetworkReply;



class DownPages : public QObject

{

    Q_OBJECT

public:

    explicit DownPages(QObject *parent = 0);

    void Do_Download();

signals:



public slots:

void replyFinished(QNetworkReply*);

void readyRead();

void downloadProgress(qint64 bytesReceived, qint64 bytesTotal);

void downFinished();

private :

    QNetworkAccessManager *manager;

    QNetworkReply * managerReply;

    QFile *file;



};



#endif // DOWNPAGES_H

 

.cpp文件

主要是添加 了这三个信号

managerReply  = manager->get(request);

    connect(managerReply,SIGNAL(readyRead()),this,SLOT(readyRead()));

    connect(managerReply,SIGNAL(downloadProgress(qint64,qint64)),

            this,SLOT(downloadProgress(qint64,qint64)));

    connect(managerReply,SIGNAL(finished()),this,SLOT(downFinished()));

readyRead()开始下载数据

DownloadProgress显示下载的进度

还有一个finished

#include "downpages.h"

#include <QNetworkRequest>

#include<QNetworkReply>

#include<QDebug>

#include<QTextCodec>

#include<QFileInfo>

#include<QDir>

DownPages::DownPages(QObject *parent) :

    QObject(parent)

{

    manager = new QNetworkAccessManager(this);

    connect(manager, SIGNAL(finished(QNetworkReply*)),

            this, SLOT(replyFinished(QNetworkReply*)));



    QUrl url;

    //url.setUrl("http://www.cnblogs.com/a/b");

    //url.setUrl("http://www.baidu.com/");

    //url.setUrl("http://www.sibaieteco.com/");

    url.setUrl("http://files.cnblogs.com/li-peng/WPFMultLanguageDemo.rar");

    QNetworkRequest request(url);



    managerReply  = manager->get(request);

    connect(managerReply,SIGNAL(readyRead()),this,SLOT(readyRead()));

    connect(managerReply,SIGNAL(downloadProgress(qint64,qint64)),

            this,SLOT(downloadProgress(qint64,qint64)));

    connect(managerReply,SIGNAL(finished()),this,SLOT(downFinished()));

}



void DownPages::Do_Download()

{



}



void DownPages::replyFinished(QNetworkReply * reply)

{



    switch(reply->error())

    {



    case QNetworkReply::NoError:

        qDebug()<<"no error";



    {

        QTextCodec * cod=QTextCodec::codecForName("utf-8");

        QString str=cod->toUnicode(reply->readAll());

        //qDebug()<<str;

    }

        break;

    case QNetworkReply::ContentNotFoundError:

    {

        QUrl failedUrl;

        failedUrl = reply->request().url();

        int httpStatus = reply->attribute(

                    QNetworkRequest::HttpStatusCodeAttribute).toInt();

        QString reason = reply->attribute( QNetworkRequest::HttpReasonPhraseAttribute ).toString();

        qDebug()<<"url"<<failedUrl <<httpStatus<<"   "<<reason;

    }

        break;

    default:

    {

        qDebug()<<"Have error"<<reply->errorString()<<" error "<<reply->error();

    }

    }

    qDebug()<<"finished";

}



void DownPages::readyRead()

{

    QFileInfo fileinfo(managerReply->url().path());

    QString thefileName = fileinfo.fileName().isEmpty()?"index.html":fileinfo.fileName();



    QString thePath ="E:/Test/Down/";

    //qDebug()<<thePath;

    QDir createfile;

    bool exist = createfile.exists(thePath);

    if(!exist)

    {

        createfile.mkpath(thePath);

    }

    thePath +=thefileName;

    file=new QFile(thePath);



//    if(file->open(QIODevice::Append))

//    {

//        file->write(managerReply->readAll());

//        file->flush();

//        file->close();

//    }

    if(file->open(QIODevice::Append ))

    {

        file->write(managerReply->readAll());

        qDebug()<<"flu";

        file->flush();

    }

    //delete file;

}



void DownPages::downloadProgress(qint64 bytesReceived, qint64 bytesTotal)

{

    qDebug()<<"Total:  "<<bytesTotal<<"  current received : "<<bytesReceived;

}



void DownPages::downFinished()

{

    file->flush();

    file->close();

    delete file;

}

 

file->open(QIODevice::Append)

枚举值	描述
QIODevice::NotOpen	未打开
QIODevice::ReadOnly	以只读方式打开
QIODevice::WriteOnly	以只写方式打开
QIODevice::ReadWrite	以读写方式打开
QIODevice::Append	以追加的方式打开，新增加的内容将被追加到文件末尾
QIODevice::Truncate	以重写的方式打开，在写入新的数据时会将原有数据全部清除，游标设置在文件开头。
QIODevice::Text	在读取时，将行结束符转换成 \n；在写入时，将行结束符转换成本地格式，例如 Win32 平台上是 \r\n
QIODevice::Unbuffered	忽略缓存