Qt发起http请求get，异步接收

get请求无参，只有网络地址，这里以请求城市天气信息为例，发起get请求，返回天气json格式数据
头文件

private:
    void queryWeather();//查询
public slots:
    void replyFinished(QNetworkReply *reply);//刷新的槽
private:
    QString cityName;
    QNetworkAccessManager *manager;  //请求句柄
    QString allinfo;       //所有信息
    //以下皆是当天，未来几天的数据框通过获取日期的数据列表
    QString date;//当前日期
    QString fengli;       //风力
    QString wendu;        //温度
    QString currentwendu;//当前温度
    QString weather_type;  //天气类型
    QString ganmao;//对于感冒提示
    bool isGetData=false;//是否成功获取数据

源文件

manager = new QNetworkAccessManager(this);  //新建QNetworkAccessManager对象
connect(manager,SIGNAL(finished(QNetworkReply*)),this,SLOT(replyFinished(QNetworkReply*)));//关联信号和槽

//查询天气
void Weather::queryWeather()
{
	cityName = "南京";
    char quest_array[256]="http://wthrcdn.etouch.cn/weather_mini?city=";
    QNetworkRequest quest;
    sprintf(quest_array,"%s%s",quest_array,cityName.toUtf8().data());
    quest.setUrl(QUrl(quest_array));
    quest.setHeader(QNetworkRequest::UserAgentHeader,"RT-Thread ART");
    /*发送get网络请求*/
    manager->get(quest);
}

//信号槽接收网络响应，处理接收到的数据
void Weather::replyFinished(QNetworkReply *reply)
{
    this->isGetData=false;
    allinfo = reply->readAll();

    QJsonParseError err;
    QJsonDocument json_recv = QJsonDocument::fromJson(allinfo.toUtf8(),&err);//解析json对象
    if(!json_recv.isNull())
    {
        QJsonObject object = json_recv.object();
        if(object.contains("data"))
        {
            QJsonValue value = object.value("data");  // 获取指定 key 对应的 value
            if(value.isObject())
            {
                QJsonObject object_data = value.toObject();
                this->cityName=object_data.value("city").toString();
                this->currentwendu=object_data.value("wendu").toString();
                this->ganmao=object_data.value("ganmao").toString();
                if(object_data.contains("forecast"))
                {
                    QJsonValue value = object_data.value("forecast");
                    if(value.isArray())
                    {
                        QJsonObject today_weather = value.toArray().at(0).toObject();
                        weather_type = today_weather.value("type").toString();
                        date = today_weather.value("date").toString();

                        QString low = today_weather.value("low").toString();
                        QString high = today_weather.value("high").toString();
                        wendu = low.mid(low.length()-3,4) +"-"+ high.mid(high.length()-3,4);
                        QString strength = today_weather.value("fengli").toString();
                        strength.remove(0,8);
                        strength.remove(strength.length()-2,2);
                        fengli = today_weather.value("fengxiang").toString() + strength;
                        this->isGetData=true;
                    }
                }
            }
        }

    }else
    {
        qDebug()<<"json_recv is NULL or is not a object !!";
    }
    reply->deleteLater(); //销毁请求对象
    if(isGetData)
    {
        qDebug()<<QString::fromLocal8Bit("获取天气成功");
    }
    else
    {
        qDebug()<<QString::fromLocal8Bit("获取天气失败");
    }
}

Qt发起http请求post，异步接收

qt发起post请求，带网络地址和参数，参数一般为json格式，转QByteArray

//发起post请求
void MainWindow::postHttpRequest()
{
    QNetworkRequest request;
    QNetworkAccessManager* naManager = new QNetworkAccessManager(this);
    QObject::connect(naManager, SIGNAL(finished(QNetworkReply*)), this, SLOT(requestFinished(QNetworkReply*)));

    request.setHeader(QNetworkRequest::ContentTypeHeader,QVariant("application/json"));
    request.setUrl(QUrl::fromUserInput(" http://192.168.1.102:2345/notice?num=4567"));

    QJsonObject obj1;
    QJsonObject object;
    object.insert("station","业务受理员");
    object.insert("name","王晨");
    object.insert("number","0001");
    object.insert("pic","http://192.168.1.15:8080/8.jpg");
    object.insert("orderNum","A123456789B");

    obj1.insert("data",object);
    obj1.insert("status","2");

    QByteArray byte_array = QJsonDocument(obj1).toJson();
    qDebug()<< "user  info " << obj1;
    QNetworkReply* reply = naManager->post(request,byte_array);//发起post请求
}

//接收网络响应槽函数
void MainWindow::requestFinished(QNetworkReply *reply)
{
    QString loginResultJson;
    QByteArray bytes = reply->readAll();
    // 获取http状态码
    QVariant statusCode = reply->attribute(QNetworkRequest::HttpStatusCodeAttribute);
    if(statusCode.isValid())
    {
        qDebug() << "status code=" << statusCode.toInt();
    }

    QNetworkReply::NetworkError err = reply->error();
    if(err != QNetworkReply::NoError)
    {
        qDebug() << "Failed: " << reply->errorString();
    }
    else
    {
        // 获取返回内容
        qDebug() << "loginResultJson  is  " <<  QString::fromStdString(bytes.toStdString());
        loginResultJson =  QString::fromStdString(bytes.toStdString());
        //处理返回数据
    }
}

Qt发起http请求get和post，收发同步

GET和POST方式均可使用，收发同步，并增加了等待接收超时处理。

/**
 * @brief http发送和接收接口
 * @param strUrl HTTP网络URL
 * @param thod HTTP方法，GET或POST
 * @param strInput 发送的数据
 * @param strMessage http返回的错误信息
 * @param strResult http接收响应
 */
void SendAndGetText(QString strUrl, QString thod, QString strInput, QString &strMessage, QString &strResult)
{
    QNetworkRequest oNetRequest;
    oNetRequest.setUrl(QUrl(strUrl));
    
    QNetworkAccessManager oNetAccessManager;
    QNetworkReply* oNetReply = nullptr;
    QByteArray inputTmp;
    
    if (thod == "POST")
    {
        oNetRequest.setRawHeader("Content-Type", "application/octet-stream");
        if(REST_TOKEN == globalHs.transType)
            oNetRequest.setRawHeader("Content-Type", "application/x-www-form-urlencoded");
        oNetReply = oNetAccessManager.post(oNetRequest, strInput.toLocal8Bit());
        //oNetReply = oNetAccessManager.post(oNetRequest, content);
    }
    else if (thod == "GET" )
    {
        oNetReply = oNetAccessManager.get(oNetRequest);
    }
    
    // 添加超时处理，10s超时
    QEventLoop eventloop;
    connect(oNetReply, SIGNAL(finished()), &eventloop, SLOT(quit()));
    QTimer::singleShot(10000, &eventloop, &QEventLoop::quit);
    eventloop.exec();
    
    QByteArray array;
    if(oNetReply->isFinished())
    {
        if(oNetReply->error() == QNetworkReply::NoError)//正常结束，读取响应数据
        {
            strResult = oNetReply->readAll();
        }
        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(oNetReply, &QNetworkReply::finished, &eventloop, &QEventLoop::quit);
        oNetReply->abort();
        qDebug()<<"["<<__FILE__<<"]"<<__LINE__<<__FUNCTION__<<" timeout";
    }
    
    QNetworkReply::NetworkError e = oNetReply->error();
    if (e)
    {
        strMessage = oNetReply->errorString();
    }
    
    oNetReply->deleteLater();
}

///调用示例
    QString url = "";//http后台地址url
    QString sendMsg = "";//http发送数据组包
    QString strMessage = "";//错误信息
    QString strResult = "";//http响应
    QString thod = "POST";//POST或GET
    SendAndGetText(url,thod,sendMsg,strMessage,strResult);

    if(strMessage.isEmpty())///HTTP正常响应
    {
        qDebug()<<"["<<__FILE__<<"]"<<__LINE__<<__FUNCTION__<<"接收数据 "<<strResult;
    }
    else///HTTP通信异常
    {
        qDebug()<<"["<<__FILE__<<"]"<<__LINE__<<__FUNCTION__<<"错误信息 "<<strMessage;
    }

http下载网络图片

/**
 * @brief 获取网络地址图片
 * @param url 图片网络地址,例如http://106.15.226.233/slImg/bg1.png
 * @return QPixmap图片
 */
QPixmap HttpGetPic::GainUrlImage(QString url)
{
    QUrl turl(url);
    QNetworkAccessManager manager;
    QEventLoop loop;
    QNetworkReply *reply = manager.get(QNetworkRequest(turl));
    //请求结束并下载完成后，退出子事件循环
    connect(reply, &QNetworkReply::finished, &loop, &QEventLoop::quit);
    //开启子事件循环
    loop.exec();
    QByteArray jpegData = reply->readAll();
    QPixmap pixmap;
    if(!pixmap.loadFromData(jpegData))
    {
        CLOG_ERROR(QString("网络地址获取图片失败，URL=%1").arg(url).toUtf8().data());
    }

    return pixmap;
}