QTcpSocket连接传入空数据问题

我正在尝试使用qtcpsocket连接在服务器和客户端之间发送数据。当我发送小尺寸数据时，一切正常。但当大小增加时，从tcpsocket读取的数据将变为空：（

//启用连接

bool ClientService::enableConnection()
{
    qDebug() << Q_FUNC_INFO << "Invoked";
    const int iTimeout = 5 * 1000;
    m_socket.connectToHost(settings.getServerIP(), PORT);
    if (!m_socket.waitForConnected(iTimeout))
    {
        emit error();
        qDebug() << Q_FUNC_INFO << m_socket.errorString();
        return false;
    }

    qDebug() << Q_FUNC_INFO << "Exits";
    return true;
}

boolclientservice:：enableConnection（）
{
qDebug（）问题已解决。：）

从客户端传递到服务器的数据大小导致了该问题。因为当数据大小变得更大时，我使用了quint16，服务器无法知道确切的传入数据大小。因此，我将类型更改为quint32。问题得到了解决

outputStream << (quint32)0;

outputStream seek（0）；
outputStream我建议使用QTcpSocket的readyRead信号让您知道数据何时可用，而不是在套接字上等待字节可用：您也可以调用flush（）将数据写入socket@Merlin069：据我所知，每次新数据可用时都会发出readyRead。因此，我应该以正确的顺序读取整个数据。这是一个问题吗？是的，每次新数据可用时都会发出readyRead，但它可能只是数据的一部分，您需要将其连接到缓冲区中。一开始发送数据大小作为第一个字节是一种好的做法，然后您就知道对readyRead的连续调用的期望值。不，我的意思是我不能使用readyRead，因为我可能无法确定哪些数据已经出现。因为我正在发送不同类型的数据，如组{}、子组{}、项{}…使用readyRead对我来说很麻烦
bool ClientService::waitForServerResponse()
{
    qDebug() << Q_FUNC_INFO << "Invoked";
    const int iTimeout = 5 * 1000;
    while (m_socket.bytesAvailable() < (int)sizeof(quint16))
    {
        if (!m_socket.waitForReadyRead(iTimeout))
        {
            emit error();
            qDebug() << Q_FUNC_INFO << m_socket.errorString();
            return false;
        }
    }

    quint16 blockSize;
    QDataStream inputStream(&m_socket);
    inputStream.setVersion(QDataStream::Qt_4_0);
    inputStream >> blockSize;

    while (m_socket.bytesAvailable() < blockSize)
    {
        if (!m_socket.waitForReadyRead(iTimeout))
        {
            emit error();
            qDebug() << Q_FUNC_INFO << m_socket.errorString();
            return false;
        }
    }

    qDebug() << Q_FUNC_INFO << "Exits";
    return true;
}

void ClientService::disableConnection()
{
    qDebug() << Q_FUNC_INFO << "Invoked";
    m_socket.disconnectFromHost();
    qDebug() << Q_FUNC_INFO << "Exits";
    return;
}

int  ClientService::syncMasters(SyncMaster syncMasterData)
{
    qDebug() << Q_FUNC_INFO << "Invoked";

    int syncStatus = -1;

    if(enableConnection())
    {
        qDebug() << Q_FUNC_INFO << "connection enabled";
        //  typecast to ensure cross platform compatibility
        const qint32 mode_int = static_cast<qint32>(SYNC_MASTERS_QUERY);
        QByteArray block;
        QDataStream outputStream(&block, QIODevice::WriteOnly);
        outputStream.setVersion(QDataStream::Qt_4_0);
        outputStream << (quint16)0;
        outputStream << mode_int;       // saying query mode to server

        // group master data
        outputStream << syncMasterData.groupMasterList.count();
        qDebug() << Q_FUNC_INFO << "groupmaster count" <<
                                    syncMasterData.groupMasterList.count();

        foreach (GroupMaster groupMasterItem, syncMasterData.groupMasterList)
        {
            outputStream << groupMasterItem.groupCode;
            outputStream << groupMasterItem.groupDescription;
            outputStream << groupMasterItem.kotPrinterNo;
            outputStream << groupMasterItem.image;
            outputStream << groupMasterItem.sortId;

            qDebug() << Q_FUNC_INFO <<
                        "code"      << groupMasterItem.groupCode         <<
                        "desc"      << groupMasterItem.groupDescription  <<
                        "kot "      << groupMasterItem.kotPrinterNo      <<
                        "image"     << groupMasterItem.image             <<
                        "sort id"   << groupMasterItem.sortId;
        }

        // subgroup master data
        outputStream << syncMasterData.subGroupMasterList.count();
        qDebug() << Q_FUNC_INFO << "subgroupmaster count" <<
                                    syncMasterData.subGroupMasterList.count();

        foreach (SubGroupMaster subGroupMasterItem,
                                syncMasterData.subGroupMasterList)
        {
            outputStream << subGroupMasterItem.groupCode;
            outputStream << subGroupMasterItem.subGroupCode;
            outputStream << subGroupMasterItem.subGroupDescription;

            qDebug() << Q_FUNC_INFO <<
                    "gpcode"    << subGroupMasterItem.groupCode     <<
                    "subgpcode" << subGroupMasterItem.subGroupCode  <<
                    "desc"      << subGroupMasterItem.subGroupDescription;
        }

        // item master data
        outputStream << syncMasterData.itemMasterList.count();
        qDebug() << Q_FUNC_INFO << "item master count" <<
                                    syncMasterData.itemMasterList.count();

        foreach (ItemMaster ItemMasterItem, syncMasterData.itemMasterList)
        {
            outputStream << ItemMasterItem.itemCode;
            outputStream << ItemMasterItem.itemName;
            outputStream << ItemMasterItem.groupCode;
            outputStream << ItemMasterItem.subGroupCode;
            outputStream << ItemMasterItem.imagePath;
            outputStream << ItemMasterItem.productId;
            outputStream << ItemMasterItem.itemPriceType;
            outputStream << ItemMasterItem.itemPrice;
            outputStream << ItemMasterItem.kotPrinterNumber;
            outputStream << ItemMasterItem.sortId;

            qDebug() << Q_FUNC_INFO <<
                        "item code"     << ItemMasterItem.itemCode      <<
                        "item name"     << ItemMasterItem.itemName      <<
                        "group code"    << ItemMasterItem.groupCode     <<
                        "subgp code"    << ItemMasterItem.subGroupCode  <<
                        "image path"    << ItemMasterItem.imagePath     <<
                        "product id"    << ItemMasterItem.productId     <<
                        "item pricetype"<< ItemMasterItem.itemPriceType <<
                        "item price"    << ItemMasterItem.itemPrice     <<
                        "kot"           << ItemMasterItem.kotPrinterNumber<<
                        "sortId"        << ItemMasterItem.sortId;
        }

        // side item master data
        outputStream << syncMasterData.sideItemMasterList.count();
        qDebug() << Q_FUNC_INFO << "side item master count" <<
                                    syncMasterData.sideItemMasterList.count();

        foreach (SideItemMaster sideItemMasterItem,
                                        syncMasterData.sideItemMasterList)
        {
            outputStream << sideItemMasterItem.itemCode;
            outputStream << sideItemMasterItem.sideItemCode;
            outputStream << sideItemMasterItem.lineNumber;
            outputStream << sideItemMasterItem.sideItemPrice;
            outputStream << sideItemMasterItem.sideItemPriceType;

            qDebug() << Q_FUNC_INFO <<
                    "item code"     << sideItemMasterItem.itemCode      <<
                    "sideitem code" << sideItemMasterItem.sideItemCode  <<
                    "line no"       << sideItemMasterItem.lineNumber    <<
                    "sideitem pric" << sideItemMasterItem.sideItemPrice <<
                    "siditm prc typ"<< sideItemMasterItem.sideItemPriceType;
        }

        // price master data
        outputStream << syncMasterData.priceMasterList.count();
        qDebug() << Q_FUNC_INFO << "price master count" <<
                                    syncMasterData.priceMasterList.count();

        foreach (PriceMaster priceMasterItem, syncMasterData.priceMasterList)
        {
            outputStream << priceMasterItem.itemCode;
            outputStream << priceMasterItem.itemPriceType;
            outputStream << priceMasterItem.promoCode;
            outputStream << priceMasterItem.validFromDate;
            outputStream << priceMasterItem.validToDate;
            outputStream << priceMasterItem.validFromTime;
            outputStream << priceMasterItem.validToTime;
            outputStream << priceMasterItem.unitCode;
            outputStream << priceMasterItem.itemPrice;
            outputStream << priceMasterItem.specialPrice;
            outputStream << priceMasterItem.unitDescription;

            qDebug() << Q_FUNC_INFO <<
                        "item code"     << priceMasterItem.itemCode         <<
                        "itm prc typ"   << priceMasterItem.itemPriceType    <<
                        "promo code"    << priceMasterItem.promoCode        <<
                        "validfrmdt"    << priceMasterItem.validFromDate    <<
                        "vld to dt"     << priceMasterItem.validToDate      <<
                        "vld frm tm"    << priceMasterItem.validFromTime    <<
                        "vld to tm"     << priceMasterItem.validToTime      <<
                        "unit code"     << priceMasterItem.unitCode         <<
                        "item price"    << priceMasterItem.itemPrice        <<
                        "spcl price"    << priceMasterItem.specialPrice     <<
                        "unit desc"     << priceMasterItem.unitDescription;
        }

        outputStream.device()->seek(0);
        outputStream << (quint16)(block.size() - sizeof(quint16));

        if(sendToServer(block))
        {
            qDebug() << Q_FUNC_INFO << "query sent to server successfully";

            if (waitForServerResponse())
            {
                qDebug() << Q_FUNC_INFO << "read set status from server";

                QDataStream inputStream(&m_socket);
                inputStream.setVersion(QDataStream::Qt_4_0);
                inputStream >> syncStatus;
            }
        }

        disableConnection();
    }

    qDebug() << Q_FUNC_INFO << "Exits" << syncStatus;
    return syncStatus;
}

void ServerFunctionThread::syncMasters()
{
    qDebug() << Q_FUNC_INFO << "Invoked";

    SyncMaster syncMasterData;

    int groupCount      = 0,
        subGroupCount   = 0,
        itemCount       = 0,
        sideItemCount   = 0,
        priceCount      = 0;

    QDataStream inputStream(&tcpSocket);
    inputStream.setVersion(QDataStream::Qt_4_0);

    // group master data reception
    inputStream >> groupCount;
    qDebug() << Q_FUNC_INFO << "group master Count" << groupCount;

    while (groupCount--)
    {
        GroupMaster groupMasterItem;
        inputStream >> groupMasterItem.groupCode;
        inputStream >> groupMasterItem.groupDescription;
        inputStream >> groupMasterItem.kotPrinterNo;
        inputStream >> groupMasterItem.image;
        inputStream >> groupMasterItem.sortId;

        syncMasterData.groupMasterList.append(groupMasterItem);

        qDebug() << Q_FUNC_INFO <<
                    "code"      << groupMasterItem.groupCode         <<
                    "desc"      << groupMasterItem.groupDescription  <<
                    "kot "      << groupMasterItem.kotPrinterNo      <<
                    "image"     << groupMasterItem.image             <<
                    "sort id"   << groupMasterItem.sortId;

    }
.
.
...

outputStream << (quint32)0;

outputStream.device()->seek(0);
outputStream << (quint32)(block.size() - sizeof(quint32));