需求

Qt 代码中使用QNetworkRequest、QNetworkReply进行http请求，能不能整理成一个通用的方法或者类。

实现

HttpClient类

#include <QObject>  
#include <QNetworkAccessManager>  
#include <QNetworkRequest>  
#include <QNetworkReply>  
#include <QUrl>  
#include <QUrlQuery>  
#include <QByteArray>  
#include <QJsonObject>  
#include <QJsonDocument>  
#include <QDebug>  
#include <QEventLoop>class HttpClient : public QObject  
{  Q_OBJECT  public:  explicit HttpClient(QObject *parent = nullptr)  : QObject(parent), networkManager(new QNetworkAccessManager(this))  {  connect(networkManager, &QNetworkAccessManager::finished, this, &HttpClient::onReplyFinished);  }  void get(const QUrl &url, const QUrlQuery &query = QUrlQuery())  {  QUrl fullUrl = url;  fullUrl.setQuery(query);  QNetworkRequest request(fullUrl);  networkManager->get(request);  eventLoot->exec();}  void post(const QUrl &url, const QByteArray &data)  {  QNetworkRequest request(url);  request.setHeader(QNetworkRequest::ContentTypeHeader, "application/json");  networkManager->post(request, data); eventLoot->exec(); }  signals:  void requestFinished(const QByteArray &responseData, QNetworkReply::NetworkError error);  private slots:  void onReplyFinished(QNetworkReply *reply)  {  if (reply->error() == QNetworkReply::NoError) {  QByteArray responseData = reply->readAll();  emit requestFinished(responseData, QNetworkReply::NoError);  } else {  emit requestFinished(QByteArray(), reply->error());  }  reply->deleteLater();  }  private:  QNetworkAccessManager *networkManager;  QEventLoop eventLoop;
};

HttpClient中使用了一个QEventLoop，为了使发送的事件得到及时的处理，不加这个的话，测试发现半天都不能调到onReplyFinished槽函数中。

使用

#include <QCoreApplication>  
#include <QUrl>  
#include <QUrlQuery>  
#include <QJsonDocument>  
#include <QJsonObject>  
#include <QByteArray>  
#include "HttpClient.h"  int main(int argc, char *argv[])  
{  QCoreApplication a(argc, argv);  HttpClient client;  // 发送GET请求  QUrl getUrl("https://jsonplaceholder.typicode.com/posts/1");  QObject::connect(&client, &HttpClient::requestFinished, [](const QByteArray &responseData, QNetworkReply::NetworkError error) {  if (error == QNetworkReply::NoError) {  QJsonDocument jsonDoc = QJsonDocument::fromJson(responseData);  QJsonObject jsonObj = jsonDoc.object();  qDebug() << "GET Response:" << jsonObj;  } else {  qDebug() << "GET Error:" << error;  }  });  client.get(getUrl);  // 发送POST请求  QUrl postUrl("https://jsonplaceholder.typicode.com/posts");  QJsonObject postData;  postData["title"] = "foo";  postData["body"] = "bar";  postData["userId"] = 1;  QByteArray postDataBytes = QJsonDocument(postData).toJson();  QObject::connect(&client, &HttpClient::requestFinished, [](const QByteArray &responseData, QNetworkReply::NetworkError error) {  if (error == QNetworkReply::NoError) {  QJsonDocument jsonDoc = QJsonDocument::fromJson(responseData);  QJsonObject jsonObj = jsonDoc.object();  qDebug() << "POST Response:" << jsonObj;  } else {  qDebug() << "POST Error:" << error;  }  });  client.post(postUrl, postDataBytes);  return a.exec();  
}