Qt之http实现get/post的两种方法

法一：异步

异步就是使用信号槽的方法实现get/post的异步方法，这样的方式不会产生阻塞，在获取到reply之前可以do other things。

get

void get(const QString &str_url){

	const QUrl url = QUrl::fromUserInput(str_url);
	QNetworkRequest qnr(url);
	QNetworkAccessManager *qnam = new QNetworkAccessManager(this);
	connect(qnam, SIGNAL(finished(QNetworkReply *)), this, SLOT(on_http_reply(QNetworkReply *)));
	qnam->get(qnr);
}

post

void post(const QString &str_url, const QString &data){

	const QUrl url = QUrl::fromUserInput(str_url);
	QNetworkRequest qnr(url);
	QNetworkAccessManager *qnam = new QNetworkAccessManager(this);
	connect(qnam, SIGNAL(finished(QNetworkReply *)), this, SLOT(on_http_reply(QNetworkReply *)));
	qnam->put(qnr, data.toUtf8());
}

void on_http_reply(QNetworkReply* reply) {
	
	QByteArray reply_data = reply->readAll();
}

法二：同步/阻塞

有时候需要等待得到返回信息才能继续做下一步。这时候用异步就超级难用了，就需要用同步/阻塞的方式了。

get

QByteArray get(const QString &str_url){

    const QUrl url = QUrl::fromUserInput(str_url);
    QNetworkRequest qnr(url);
    QNetworkAccessManager qnam;
    QNetworkReply *reply = qnam.get(qnr);
    QEventLoop eventloop;
    QObject::connect(reply, &QNetworkReply::finished, &eventloop, &QEventLoop::quit);
    eventloop.exec(QEventLoop::ExcludeUserInputEvents);
    QByteArray reply_data = reply->readAll();
    reply->deleteLater();
    reply = nullptr;
    return reply_data;
}

post

QByteArray post(const QString &str_url, const QString &data){

    const QUrl url = QUrl::fromUserInput(str_url);
    QNetworkRequest qnr(url);
    QNetworkAccessManager qnam;
    QNetworkReply *reply = qnam.put(qnr, data.toUtf8());
    QEventLoop eventloop;
    QObject::connect(reply, &QNetworkReply::finished, &eventloop, &QEventLoop::quit);
    eventloop.exec(QEventLoop::ExcludeUserInputEvents);
    QByteArray reply_data = reply->readAll();
    reply->deleteLater();
    reply = nullptr;
    return reply_data;
}