浅谈Qt实现HTTP的Get/Post请求
时间：2022-09-12 10:14:58|栏目：C代码|点击： 次
借助Qt的NetWork模块，可以轻松的实现HTTP的Get/Post请求，而不需要再次引用像libcurl这样的第三方库。
当然，Qt的NetWork模块提供的功能远远不只是HTTP方面的。
头文件
#include <QNetworkRequest> #include <QNetworkReply> #include <QNetworkAccessManager>
另外，使用Qt网络模块还需要引用Qt5Network.lib库。
Get
先构造一个QNetworkAccessManager对象，QNetworkAccessManager对象提供了发送QNetworkRequest网络请求和接收QNetworkReply网络回复的功能。
QNetworkAccessManager还提供了缓存和Cookie管理、代理设置等功能。详见：https://doc.qt.io/qt-5/qnetworkaccessmanager.html
QNetworkRequest提供了对本次网络请求的封装，在本示例中只是构造了一个最简单的requset，没有进行任何参数设置。QNetworkRequest提供了很多方法来对请求进行配置，比如我们可以使用QNetworkRequest::setHeader设置请求头等。详见：https://doc.qt.io/qt-5/qnetworkrequest.html
void QtGuiApplication::onBtnGetClicked() {
QNetworkRequest request;
QNetworkAccessManager* naManager = new QNetworkAccessManager(this);
QMetaObject::Connection connRet = QObject::connect(naManager, SIGNAL(finished(QNetworkReply*)), this, SLOT(requestFinished(QNetworkReply*)));
Q_ASSERT(connRet);
request.setUrl(QUrl("https://www.baidu.com"));
QNetworkReply* reply = naManager->get(request);
}
请求是异步的，当请求完成之后，会调用void requestFinished(QNetworkReply* reply);槽函数：
void QtGuiApplication::requestFinished(QNetworkReply* reply) {
// 获取http状态码
QVariant statusCode = reply->attribute(QNetworkRequest::HttpStatusCodeAttribute);
if(statusCode.isValid())
qDebug() << "status code=" << statusCode.toInt();
QVariant reason = reply->attribute(QNetworkRequest::HttpReasonPhraseAttribute).toString();
if(reason.isValid())
qDebug() << "reason=" << reason.toString();
QNetworkReply::NetworkError err = reply->error();
if(err != QNetworkReply::NoError) {
qDebug() << "Failed: " << reply->errorString();
}
else {
// 获取返回内容
qDebug() << reply->readAll();
}
}
Post
void QtGuiApplication::onBtnPushClicked() {
QNetworkRequest request;
QNetworkAccessManager* naManager = new QNetworkAccessManager(this);
QMetaObject::Connection connRet = QObject::connect(naManager, SIGNAL(finished(QNetworkReply*)), this, SLOT(requestFinished(QNetworkReply*)));
Q_ASSERT(connRet);
request.setUrl(QUrl("https://www.baidu.com"));
QString testData = "test";
QNetworkReply* reply = naManager->post(request, testData.toUtf8());
}
同样，请求也是异步的，当请求完成之后，会调用void requestFinished(QNetworkReply* reply);槽函数（和Get一样）：
void QtGuiApplication::requestFinished(QNetworkReply* reply) {
// 获取http状态码
QVariant statusCode = reply->attribute(QNetworkRequest::HttpStatusCodeAttribute);
if(statusCode.isValid())
qDebug() << "status code=" << statusCode.toInt();
QVariant reason = reply->attribute(QNetworkRequest::HttpReasonPhraseAttribute).toString();
if(reason.isValid())
qDebug() << "reason=" << reason.toString();
QNetworkReply::NetworkError err = reply->error();
if(err != QNetworkReply::NoError) {
qDebug() << "Failed: " << reply->errorString();
}
else {
// 获取返回内容
qDebug() << reply->readAll();
}
}
