Qt网络编程之实例一GET方式
看了两天的Qt网络编程,其实主要就是看了看QNetworkAccessManager、QNetworkRequest和QNetworkReply这三个类的主要内容。在之前,Qt网络编程主要是使用QHttp等类,但是现在在帮助手册中这些类已经标记为过时的,所以,现在用Qt编写网络程序最好还是使用上面的三个类,之前也说过,对于一个应用程序来说,一个QNetworkAccessManager已经足够了。不知道你有没有通过名字看出这三个类的联系呢?这里再贴一下三个类的官方说明,加强印象,也有助于大家对照接下来的示例看。
Allows the application to send network requests and receive replie Holds a request to be sent with QNetworkAccessManager Contains the data and headers for a request sent with QNetworkAccessManager |
接下来就看一个示例,其实主要内容还是Nokia给的示例,但是源程序有错误之处,我这里进行修改了,这里先贴一下效果:
再来贴一下主要的代码,代码简单,一看就懂,呵呵:
#include "mainwindow.h" #include "ui_mainwindow.h" #include <QNetworkReply> #include <QNetworkRequest> MainWindow::MainWindow(QWidget *parent) : QMainWindow(parent), ui(new Ui::MainWindow) { ui->setupUi(this); nam = new QNetworkAccessManager(this); QObject::connect(nam, SIGNAL(finished(QNetworkReply*)), this, SLOT(finishedSlot(QNetworkReply*))); } MainWindow::~MainWindow() { delete ui; } void MainWindow::on_pushButton_clicked() { QUrl url("http://www.hust.edu.cn/"); QNetworkReply* reply = nam->get(QNetworkRequest(url)); // NOTE: Store QNetworkReply pointer (maybe into caller). // When this HTTP request is finished you will receive this same // QNetworkReply as response parameter. // By the QNetworkReply pointer you can identify request and response. } void MainWindow::finishedSlot(QNetworkReply *reply) { #if 1 // Reading attributes of the reply // e.g. the HTTP status code QVariant statusCodeV = reply->attribute(QNetworkRequest::HttpStatusCodeAttribute); // Or the target URL if it was a redirect: QVariant redirectionTargetUrl = reply->attribute(QNetworkRequest::RedirectionTargetAttribute); // see CS001432 on how to handle this // no error received? if (reply->error() == QNetworkReply::NoError) { // read data from QNetworkReply here // Example 1: Creating QImage from the reply //QImageReader imageReader(reply); //QImage pic = imageReader.read(); // Example 2: Reading bytes form the reply QByteArray bytes = reply->readAll(); // bytes //QString string(bytes); // string QString string = QString::fromUtf8(bytes); ui->textBrowser->setText(string); } // Some http error received else { // handle errors here } // We receive ownership of the reply object // and therefore need to handle deletion. reply->deleteLater(); #endif }
好了,今天就到了!