QT之Http请求

今天我们介绍一下QT的http请求，这里有post和get两种方式

一、post请求方式：参数分为网址和具体请求值两个部分，有时候还需要设置头信息，看具体情况定

 void MainWindow::sendPostRequest()
 {
     QNetworkAccessManager *m_pHttpMgr = new QNetworkAccessManager();
     //设置url
     QString url = "http://10.0.0.20:8005/order/charge";
     //设置头信息
     QNetworkRequest requestInfo;
     requestInfo.setUrl(QUrl(url));
     requestInfo.setHeader(QNetworkRequest::ContentTypeHeader,QVariant("application/json"));
 //  requestInfo.setRawHeader("Content-Type","application/json");//服务器要求的数据头部
 //  requestInfo.setRawHeader("Accept","text/json,*/*;q=0.5");//服务器要求的数据头部

     //发送数据
     QByteArray qByteHttpData = sendJson();
     QNetworkReply *reply =  m_pHttpMgr->post(requestInfo, qByteHttpData);
     //添加事件循环机制，返回后再运行后面的
     QEventLoop eventLoop;
     connect(reply, SIGNAL(finished()), &eventLoop, SLOT(quit()));
     eventLoop.exec();       //block until finish

     //错误处理
     if (reply->error() == QNetworkReply::NoError)
     {
         qDebug() << "request protobufHttp NoError";
     }
     else
     {
         qDebug()<<"request protobufHttp handle errors here";
         QVariant statusCodeV = reply->attribute(QNetworkRequest::HttpStatusCodeAttribute);
         //statusCodeV是HTTP服务器的相应码，reply->error()是Qt定义的错误码，可以参考QT的文档
         qDebug( "request protobufHttp found error ....code: %d %d\n", statusCodeV.toInt(), (int)reply->error());
         qDebug(qPrintable(reply->errorString()));
     }

     //请求收到的结果
     QByteArray responseByte = reply->readAll();
 ｝

二、get请求方式：参数和网址拼接到一起请求

 void MainWindow::sendGetRequest()
 {
     QNetworkAccessManager *m_pHttpMgr = new QNetworkAccessManager();
     //设置url
     QString url = "http://10.0.0.20:8005/vending_machine/items/ac83f39ea268";//fae4b325e52c
     QNetworkRequest requestInfo;
     requestInfo.setUrl(QUrl(url));

     //添加事件循环机制，返回后再运行后面的
     QEventLoop eventLoop;
     QNetworkReply *reply =  m_pHttpMgr->get(requestInfo);
     connect(reply, SIGNAL(finished()), &eventLoop, SLOT(quit()));
     eventLoop.exec();       //block until finish
     //错误处理
     if (reply->error() == QNetworkReply::NoError)
     {
         qDebug() << "request protobufHttp NoError";
     }
     else
     {
         qDebug()<<"request protobufHttp handle errors here";
         QVariant statusCodeV = reply->attribute(QNetworkRequest::HttpStatusCodeAttribute);
         //statusCodeV是HTTP服务器的相应码，reply->error()是Qt定义的错误码，可以参考QT的文档
         qDebug( "request protobufHttp found error ....code: %d %d\n", statusCodeV.toInt(), (int)reply->error());
         qDebug(qPrintable(reply->errorString()));
     }
     //请求返回的结果
     QByteArray responseByte = reply->readAll();
     qDebug() << responseByte;
 ｝

三、主要区别：

get用于请求获取数据，post向指定的资源创建修改数据

get把参数包含在URL中（长度有限制），POST通过请求实体传递参数（安全）