Qt網絡開發之QNetworkAccessManager使用要點

 要點一：對於一個應用程序，一個QNetworkAccessManager就足夠了，當然使用多個QNetworkAccessManager也是沒有問題的,Webkit中一個QWebpage只會使用一個QNetworkAccessManager。

    要點二：每一個回復QNetworkReply都需要刪除，否則會出現內存泄露，根據Qt的幫助文檔，在接收完數據的槽中使用deleteLater()，防止內存泄露。

 MyNetManager.h

 

#ifndef MYNETMANAGER_H

#define MYNETMANAGER_H

#include <QObject>

#include <QNetworkAccessManager>

class MyNetManager : public QObject

{

    Q_OBJECT

public:

    explicit MyNetManager(QNetworkAccessManager *pManager);

    ~MyNetManager();

    bool get(QUrl url);

    bool post(QUrl url,QByteArray& bytes);

signals:

public slots:

    void downloadProgress(qint64 bytesSent, qint64 bytesTotal);

    void finished();

private:

    QNetworkAccessManager *m_pManager;

};

#endif // MYNETMANAGER_H

 

MyNetManager.cpp

#include "mynetmanager.h"

#include <QUrl>

#include <QByteArray>

#include <QNetworkRequest>

#include <QNetworkReply>

#include <iostream>

using namespace std;

MyNetManager::MyNetManager(QNetworkAccessManager *parent) :

    m_pManager(parent){

}

MyNetManager::~MyNetManager(){

}

bool MyNetManager::get(QUrl url){

    QNetworkRequest request;

    request.setUrl(url);

    QNetworkReply *reply = m_pManager->get(request);

    connect(reply,SIGNAL(finished()),this,SLOT(finished()));

    connect(reply,SIGNAL(downloadProgress(qint64,qint64)),

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

    return true;

}

bool MyNetManager::post(QUrl url, QByteArray &bytes){

    QNetworkRequest request;

    request.setUrl(url);

    QNetworkReply *reply = m_pManager->post(request,bytes);

    connect(reply,SIGNAL(downloadProgress(qint64,qint64)),

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

    return true;

}

void MyNetManager::finished(){

    QNetworkReply* reply = (QNetworkReply*)sender();

    reply->deleteLater();

}

void MyNetManager::downloadProgress(qint64 bytesSent, qint64 bytesTotal){

    cout<< "\ndownloadProgress done:\n";

    cout << "bytesSent: " << bytesSent

         << "  " << "bytesTocal: " << bytesTotal;

}

main.cpp

#include "mynetmanager.h"

#include <QCoreApplication>

#include <QUrl>

int main(int argc, char *argv[])

{

    QCoreApplication a(argc, argv);

    QNetworkAccessManager *netManager =new QNetworkAccessManager();

    MyNetManager manager(netManager);

    manager.get(QUrl("http://blog.csdn.net/u010002704"));

    return a.exec();

}

//以下來自Qt文檔

QNetworkAccessManager *manager = new QNetworkAccessManager(this);

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

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

manager->get(QNetworkRequest(QUrl("http://qt-project.org")));

QNetworkRequest request;

request.setUrl(QUrl("http://qt-project.org"));

request.setRawHeader("User-Agent", "MyOwnBrowser 1.0");

QNetworkReply *reply = manager->get(request);

connect(reply, SIGNAL(readyRead()), this, SLOT(slotReadyRead()));

connect(reply, SIGNAL(error(QNetworkReply::NetworkError)),

        this, SLOT(slotError(QNetworkReply::NetworkError)));

connect(reply, SIGNAL(sslErrors(QList<QSslError>)),

        this, SLOT(slotSslErrors(QList<QSslError>)));