Qt中Udp通信

        Qt中提供了QUdpSocket支持Udp通信。

        在Udp通信中，一个Udp对象绑定端口后即可收发数据。数据可以广播也可以单播放。比较简单。

帮助文档代码示例：

void Server::initSocket()
  {
      udpSocket = new QUdpSocket(this);
      udpSocket->bind(QHostAddress::LocalHost, 7755);
      connect(udpSocket, &QUdpSocket::readyRead,
              this, &Server::readPendingDatagrams);
  }

  void Server::readPendingDatagrams()
  {
      while (udpSocket->hasPendingDatagrams()) {
          QNetworkDatagram datagram = udpSocket->receiveDatagram();
          processTheDatagram(datagram);
      }
  }

        示例代码：

//初始化
int port;
QUdpSocket *udpSocket;
port = 5555;
udpSocket = new QUdpSocket(this);
connect(udpSocket,&QUdpSocket::readyRead,this,&UdpClient::dataReceived);
bool result = udpSocket->bind(port);
if(!result){
    QMessageBox::information(this,tr("error"),tr("udp socket create error"));
    return;
}
//接收数据
void UdpClient::dataReceived(){
    while(udpSocket->hasPendingDatagrams()){
        QByteArray datagram;
        datagram.resize(udpSocket->pendingDatagramSize());
        udpSocket->readDatagram(datagram.data(),datagram.size());
        QString msg = datagram.data();
        receiveTextEdit->insertPlainText(msg);
    }
}
//发送数据
if((length = udpSocket->writeDatagram(msg.toLatin1(),msg.length(),QHostAddress::Broadcast,port))!=msg.length()){
        return;
    }