QT5网络编程笔记 单客户端与多客户端

    //QHostInfo类作用，获取主机名，也可以通过主机名来查找IP地址，或者通过IP地址来反向查找主机名。

    QString localHostName = QHostInfo::localHostName();   //获取计算机名称

    qDebug() << "LocalHostName:" << localHostName;

    //获取IP地址

    QHostInfo info = QHostInfo::fromName(localHostName);  //获取ip地址，包括ipv6

    qDebug() << "IP Address:" << info.addresses();

    foreach(QHostAddress address, info.addresses())  //取出IPv4地址

    {

        if (address.protocol() == QAbstractSocket::IPv4Protocol) 

          qDebug() << "IPv4 Address:" << address.toString();

          ui->comboBox->addItem(address.toString());

    }

    foreach (QHostAddress address, QNetworkInterface::allAddresses())//去除所有地址包括127.0.0.1

    {

        qDebug() << "Address:" << address;

   }

 服务器端设置：

        QTcpserver QTcpsocket

     QTcpserver主要负责监听端口，如果有链接 获得客户端套接字

 if(ui->port->text().isEmpty())

       {

           QMessageBox::about(this,tr("提示"),tr("端口没有设置"));

       }

       if(ui->listen->text() == tr("侦听"))

       {

           //从输入框获取端口号

           int port = ui->port->text().toInt();

           //监听指定的端口

           if(!m_tcpserver->listen(QHostAddress::Any, port))

           {

               //若出错，则输出错误信息

               qDebug()<<m_tcpserver->errorString();

               return;

           }

           qDebug()<< "Listen succeessfully!";

       }

  当监听到链接时会产生newconnect()信号，然后创建客户端套接字 （这个是单客户端）

  //获取客户端连接

    m_tcpsocket = m_tcpserver->nextPendingConnection();

    //连接QTcpSocket的信号槽，以读取新数据

    QObject::connect(m_tcpsocket, &QTcpSocket::readyRead, this, &MainWindow::socket_Read_Data);

    QObject::connect(m_tcpsocket, &QTcpSocket::disconnected, this, &MainWindow::socket_Disconnected);

    ui->show->append(m_tcpsocket->peerAddress().toString());  //获得客户端的ip地址

    //发送按键使能

    ui->send->setEnabled(true);

    qDebug() << "A Client connect!";

将textedit的数据送到指定的客户端上，

    qDebug()<<"send:"<<ui->sendtext->toPlainText(); 

   QByteArray datasend=ui->sendtext->toPlainText().toLocal8Bit();

    m_tcpsocket->write(datasend);

    m_tcpsocket->flush();

    ui->sendtext->clear();

读取网络数据并解析：

  QByteArray requestData;

    //读取缓冲区数据

    requestData = m_tcpsocket->readAll();

    if(requestData.at(0)==102)

    {

                  twoBytes=requestData.mid(1,4); //

                  int j = twoBytes[3] & 0x000000ff;

                  j |= ((twoBytes[2] << 8) & 0x0000ff00);

                  j |= ((twoBytes[1] << 16) & 0x00ff0000);

                  j |= ((twoBytes[0] << 24) & 0xff000000);

                   twoBytes2=requestData.mid(5,4); //

                  int d = twoBytes2[3] & 0x000000ff;

                  d |= ((twoBytes2[2] << 8) & 0x0000ff00);

                  d |= ((twoBytes2[1] << 16) & 0x00ff0000);

                  d |= ((twoBytes2[0] << 24) & 0xff000000);

                   twoBytes3=requestData.mid(9,4);//

                  int m = twoBytes3[3] & 0x000000ff;

                  m |= ((twoBytes3[2] << 8) & 0x0000ff00);

                  m |= ((twoBytes3[1] << 16) & 0x00ff0000);

                  m |= ((twoBytes3[0] << 24) & 0xff000000);

                   twoBytes4=requestData.mid(13,4);//

                  union MyUnion

                  {

                    unsigned char info[4];

                    float f;

                  }FLOAT_DATA;

                  FLOAT_DATA.info[0]=twoBytes4[0];

                  FLOAT_DATA.info[1]=twoBytes4[1];

                  FLOAT_DATA.info[2]=twoBytes4[2];

                  FLOAT_DATA.info[3]=twoBytes4[3];

                  twoBytes5=requestData.mid(17,4);

                  union YouUnion

                  {

                    unsigned char info[4];

                    float f;

                  }FLOAT_DATA1;

                  FLOAT_DATA1.info[0]=twoBytes5[0];

                  FLOAT_DATA1.info[1]=twoBytes5[1];

                  FLOAT_DATA1.info[2]=twoBytes5[2];

                  FLOAT_DATA1.info[3]=twoBytes5[3];

      }

                  requestData.clear();    //清除缓冲区

多客户端与单客户端的区别在于产生newconnect()信号时的处理方式

 m_tcpsocket = m_tcpserver->nextPendingConnection();

    socket_list->append(m_tcpsocket); //定义一个QList数据类型的对象，存储链接的客户端套接字信息。

    //连接QTcpSocket的信号槽，以读取新数据

    QObject::connect(m_tcpsocket, &QTcpSocket::readyRead, this, &MainWindow::socket_Read_Data);

    QObject::connect(m_tcpsocket, &QTcpSocket::disconnected, this, &MainWindow::socket_Disconnected);

    ui->show->append(m_tcpsocket->peerAddress().toString());

    //发送按键使能

    ui->send->setEnabled(true);

    qDebug() << "A Client connect!";

多客户端解析数据时的方式

 QByteArray message;

    for(int i = 0;i < socket_list->length();i ++)

        {

           message = socket_list->at(i)->readAll() ;

           if(!message.isEmpty())

           {

               qDebug()<< message;

           }