原文：https://blog.csdn.net/uyy203/article/details/51047095

定义

udpSocket = new QUdpSocket(this); 
QByteArray datagram = "http://blog.csdn.net/uyy203"; 
udpSocket->writeDatagram(datagram.data(), datagram.size(), QHostAddress::Broadcast, 8686); 
udpSocket->bind(QHostAddress("192.168.191.10"), 8686); 

UDP客户端广播

QUdpSocket *udpsocket1 = new QUdpSocket(this);
QByteArray datagram = "http://blog.csdn.net/uyy203"; udpsocket1->writeDatagram(datagram.data(),datagram.size(), QHostAddress::Broadcast,ui->spinBox->text().toInt());

UDP客户端发送到指定IP

QUdpSocket *udpsocket1 = new QUdpSocket(this);
QByteArray datagram = "http://blog.csdn.net/uyy203"; udpsocket1->writeDatagram(datagram.data(),datagram.size(), QHostAddress("192.168.191.10"),ui->spinBox->text().toInt());

收数据

connect(udpsocket, SIGNAL(readyRead()), this, SLOT(readPendingDatagrams())); 
while (udpsocket->hasPendingDatagrams()) 
{ 
QByteArray datagram; 
datagram.resize(udpsocket->pendingDatagramSize()); 
QHostAddress sender; 
quint16 senderPort; 
udpsocket->readDatagram(datagram.data(), datagram.size(), &sender, &senderPort); 
qDebug()<<datagram.data()<<datagram.size()<<senderPort<<sender.toString(); //processTheDatagram(datagram);
}

获取本地IP

QString getLocalIP(){
 
 
    QList<QHostAddress> list = QNetworkInterface::allAddresses();
        foreach (QHostAddress address, list)
        {
           if(address.protocol() == QAbstractSocket::IPv4Protocol)
               return address.toString();
           }
        return  "";
}

本地IP和端口绑定

bool Connect(QString IP,QString port)
{
    udpReceiverSocket->close();
    udpSenderSocket->close();
    bindReceiverFlag=bindSenderFlag=false;
 
 
    bindReceiverFlag=udpReceiverSocket->bind(QHostAddress(IP),port.toInt());
    bindSenderFlag=udpSenderSocket->bind(port.toInt());
 
 
 
 
    if(bindReceiverFlag&&bindSenderFlag)
        return true;
    else
        return false;
 
 
}

接收数据，获取数据长度，发送方IP，发送方端口

udpReceiverSocket->readDatagram(datagram.data(), datagram.size(),&senderIP,&senderPort);