Qt学习笔记网络(一)
时间:2022-04-25
本文章向大家介绍Qt学习笔记网络(一),主要内容包括其使用实例、应用技巧、基本知识点总结和需要注意事项,具有一定的参考价值,需要的朋友可以参考一下。
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 rn |
QIODevice::Unbuffered |
忽略缓存 |
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