C++ 如何在Qt中实现一个简单的tcp连接?

C++ 如何在Qt中实现一个简单的tcp连接?,c++,qt,qtcpsocket,qtcpserver,C++,Qt,Qtcpsocket,Qtcpserver,我试图修改Qt网络教程,并实现如下: quint16 blockSize; void Client::readData() { qDebug() << "Received Data!"; QByteArray data; QDataStream in(tcpSocket); in.setVersion(QDataStream::Qt_4_0); if (blockSize == 0) { if (tcpSocket->

我试图修改
Qt
网络教程,并实现如下:

quint16 blockSize;

void Client::readData()
{
    qDebug() << "Received Data!";
    QByteArray data;

    QDataStream in(tcpSocket);
    in.setVersion(QDataStream::Qt_4_0);

    if (blockSize == 0) {
        if (tcpSocket->bytesAvailable() < (int)sizeof(quint16))
            return;

        in >> blockSize;
    }

    qDebug() << "Received DATA II with blocksize " << blockSize;
    if (tcpSocket->bytesAvailable() < blockSize)
    {
        qDebug() << tcpSocket->bytesAvailable() << ' ' << blockSize;
        return;
    }
    qDebug() << "Received DATA III";
    in >> data;
    qDebug() << data;
    QByteArray dbg = data;   // create a copy to not alter the buffer itself
    dbg.replace('\\', "\\\\"); // escape the backslash itself
    dbg.replace('\0', "\\0");  // get rid of 0 characters
    dbg.replace('\n', "\\n");
    //dbg.replace('"', "\\\"");  // more special characters as you like
    qDebug() << dbg;
    QString data_string(data);
    qDebug() << "Emitting Signal";
    emit Client::gotData(data_string);

}

void Server::sendData(void)
{
        QByteArray block;
        QDataStream out(&block, QIODevice::WriteOnly);
        out.setVersion(QDataStream::Qt_4_0);
        out << (quint16)0;
        out << "Hello World, this is a very long text!";
        out.device()->seek(0);
        out << (quint16)(block.size() - sizeof(quint16));
        qDebug() << "First number is: " << (quint16)(block.size() - sizeof(quint16));
        qDebug() << "Blocksize is: " << block.size() << "with quint size: " << sizeof(quint16);

        qDebug() << "Sending data!";
        //Debug
        QByteArray dbg = block;   // create a copy to not alter the buffer itself
        dbg.replace('\\', "\\\\"); // escape the backslash itself
        dbg.replace('\0', "\\0");  // get rid of 0 characters
        dbg.replace('\n', "\\n");
        //dbg.replace('"', "\\\"");  // more special characters as you like
        qDebug() << dbg;
        connect(clientConnection, SIGNAL(disconnected()), clientConnection, SLOT(deleteLater()));
        clientConnection->write(block);
        //clientConnection->disconnectFromHost();
}
我的第一个问题是:所有的
\0
从哪里来?就我对代码的理解而言,首先我要创建一个
0
,然后我写文本,然后我回到前面,写块的完整大小。是因为
(quint16)
的大小吗?当不输入任何内容时,我得到的是
\0\0
,大小为0,这是正确的。上面示例的大小是43,对应于ascii中的
+
(该符号也在上面的块中)。
我的第二个问题是:My
readData()
-函数无法识别块大小(它总是返回450作为块大小,这显然是错误的)。为什么?我错过什么了吗?

更新:更改
QByteArray数据后
QString数据我的问题消失了,我的代码中没有更奇怪的
\0
应该使用正确的数据类型->头部->桌面

块大小的确切类型是什么?
quint16
是类型,只是将它添加到主要问题中,它在真实代码中是否正确初始化?(例如,在该类的构造函数中)我认为是这样,在
Client::Client(){…blockSize=0;…}First number is:  43
Blocksize is:  45 with quint size:  2
Sending data!
"\0+\0\0\0'Hello World, this is a very long text!\0"