UDP不用怎么介绍吧，算了。。。。还是写出来好了。。。。。
UDP协议格式很简单，定义好IP 与port就可以了。
MyUDP::MyUDP(QObject *parent) :
QObject(parent)
{
socket = new QUdpSocket(this);
socket->bind(QHostAddress::LocalHost,1234);
connect(socket,SIGNAL(readyRead()),this,SLOT(readyRead()));
}
void MyUDP::SayHello()
{
QByteArray Data;
Data.append("Hello UDP land!");
socket->writeDatagram(Data,QHostAddress::LocalHost,1234);
}
void MyUDP::readyRead()
{
QByteArray Buffer;
Buffer.resize(socket->pendingDatagramSize());
QHostAddress sender;
quint16 senderPort;
socket->readDatagram(Buffer.data(),Buffer.size(),&sender,&senderPort);
qDebug() << " Message from " <<sender.toString();
qDebug() << " Message port " <<senderPort;
qDebug() << " Message " <<Buffer;
}
