【Qt-9】HTTP请求（post方式）_WXG1011的博客-CSDN博客
【QT-6】QWebApp服务器搭建及使用_qtwebapp_WXG1011的博客-CSDN博客
写在前面：在上面两篇博文的基础上，继续迭代功能。
上面两篇博客已实现QWebApp服务器搭建、http通信发送请求及接收响应数据等功能。下面实现多层http通信。
采用异步接收响应数据时一直报无法读取内存的错误，故采用同步接收响应数据的方式。这里http请求方式采用Get形式。
伪代码如下：
void MeasurementController::PostRequestM(QString url)
{
//http请求
QNetworkRequest request1;
QNetworkAccessManager nam;
//connect(&nam, &QNetworkAccessManager::finished, this, &MeasurementController::receivePostReply);
qDebug() << "request data!";
request1.setUrl(QUrl(url)); //实时请求网址
qDebug() << "request end!";
//request1.setUrl(QUrl("http://10.1.101.195:8085/measurement")); //实时请求网址
//请求头token设置
/*request1.setHeader(QNetworkRequest::ContentTypeHeader, QVariant("application/json;charset=utf-8"));
QString token = "xxxxxxxxxxxxxxxxxxxxxxxx";
QString token_headerData = token;
request1.setRawHeader("token", token_headerData.toLocal8Bit());*/
//QNetworkReply* reply = nam.post(request1, byte_array); //post请求头+传输的数据
QNetworkReply* reply = nam.get(request1); //get请求头
//开启事件循环，直到请求完成
QEventLoop loop;
connect(reply, SIGNAL(finished()), &loop, SLOT(quit()));
//connect(reply, &QNetworkReply::finished, &loop, &QEventLoop::quit);
loop.exec();
QString strMessage = "";//错误信息
QString strResult = "";//http响应
QByteArray array;
if (reply->isFinished())
{
if (reply->error() == QNetworkReply::NoError)//正常结束，读取响应数据
{
strResult = reply->readAll();
qDebug() << strResult;
res = strResult.toUtf8();
}
else//异常结束，比如不存在的http服务器，错误信息：Connection refused
{
}
}
else//超时,错误信息：Operation canceled
{
disconnect(reply, &QNetworkReply::finished, &loop, &QEventLoop::quit);
reply->abort();
qDebug() << "[" << __FILE__ << "]" << __LINE__ << __FUNCTION__ << " timeout";
}
QNetworkReply::NetworkError e = reply->error();
if (e)
{
strMessage = reply->errorString();
}
reply->deleteLater();
}