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 ；在写入时，将行结束符转换成本地格式，例如 Win32 平台上是
QIODevice::Unbuffered	忽略缓存