在專案中需要將本地的一個資料夾上傳到伺服器，於是想到先將起壓縮成ZIP檔案，然後上傳。壓縮功能的做法見另一篇博文Qt將資料夾壓縮成ZIP檔案.
由於經驗所限，不太懂網路程式設計。根據例子，使用 QNetworkAccessManager 和 QNetworkRequest 上傳檔案內容，總是錯誤。最後在一些好友的幫助下，終於解決了問題，記下來備忘。也希望給遇到類似問題的同學一個幫助。由於沒有弄懂真正的原理和機制，僅貼出程式碼，給有需要的同學參考。

介面文件說明：

上傳實現函式：

把程式碼也粘上：

void UploadFile_API::sendRequest(const QString &
 
userName, const QString &teacherSession, const QString &zipfile)
{
    status = -1;
    msg = QStringLiteral("連線超時，請檢查您的網路設定。");

    //從伺服器取得時間戳
    UnixTimeAPI unixTimeAPI;
    if (!unixTimeAPI.isOK())
    {
        qWarning()<<Q_FUNC_INFO<<"Obtain UnixTime failed.";
        return
 
;
    }

    //設定傳送的資料
    uint unixTime_s = unixTimeAPI.getUnixTime_s();
    QHttpMultiPart *multiPart = new QHttpMultiPart(QHttpMultiPart::FormDataType);

    QHttpPart signaturePart;
    signaturePart.setHeader(QNetworkRequest::ContentDispositionHeader, QVariant(QString("form-data; name=\"%1\"").arg("signature"
 
)));
    signaturePart.setBody(NetworkServerUtil::getSignature(unixTime_s).toLatin1());

    QHttpPart utPart;
    utPart.setHeader(QNetworkRequest::ContentDispositionHeader, QVariant(QString("form-data; name=\"%1\"").arg("unix_time")));
    utPart.setBody(QString::number(unixTime_s).toLatin1());

    QHttpPart tiPart;
    tiPart.setHeader(QNetworkRequest::ContentDispositionHeader, QVariant(QString("form-data; name=\"%1\"").arg("teacher_id")));
    tiPart.setBody(userName.toLatin1());

    QHttpPart tsPart;
    tsPart.setHeader(QNetworkRequest::ContentDispositionHeader, QVariant(QString("form-data; name=\"%1\"").arg("teacher_session")));
    tsPart.setBody(teacherSession.toLatin1());

    QHttpPart imagePart;
    imagePart.setHeader(QNetworkRequest::ContentDispositionHeader, QVariant(QString("form-data; name=\"%1\"; filename=\"%2\"").arg("zipfile").arg(QFileInfo(zipfile).fileName())));
    QFile *file = new QFile(zipfile);
    file->open(QIODevice::ReadOnly);
    imagePart.setBodyDevice(file);
    file->setParent(multiPart); // we cannot delete the file now, so delete it with the multiPart

    multiPart->append(signaturePart);
    multiPart->append(utPart);
    multiPart->append(tiPart);
    multiPart->append(tsPart);
    multiPart->append(imagePart);

    //設定頭資訊
    QNetworkRequest networkRequest;
    networkRequest.setUrl(QUrl(QString("http://%1/tsp/uploadfile").arg(NetworkServerUtil::getStableIP())));

    //傳送請求
    QNetworkReply *networkReply = m_networkManager->post(networkRequest, multiPart);
    multiPart->setParent(networkReply); // delete the multiPart with the reply
}