基于QT编写的UDP的广播与组播实例

#include "mainwindow.h" #include "ui_mainwindow.h" #include <QHostInfo> MainWindow::MainWindow(QWidget *parent) : QMainWindow(parent), ui(new Ui::MainWindow) { ui->setupUi(this); //本地主机名 QString hostName = QHostInfo::localHostName(); m_udpSocket = new QUdpSocket(this); //socket QAbstractSocket::MulticastTtlOption值为1，MulticastTtlOption是 //组播的数据的生存期，数据报没跨1个路由就会减1.表示多播数据报只能在同一路由下的局域网内传播 m_udpSocket->setSocketOption(QAbstractSocket::MulticastTtlOption, 1); connect(m_udpSocket, SIGNAL(readyRead()), this, SLOT(on_readyRead())); /* 1 )发送 知道端口；设置 组播的数据的生存期 setSocketOption(QAbstractSocket::MulticastTtlOption, 1); 发送到指定的组IP 2）接收 设置信号槽， 绑定端口， 加入组 IP groupAddress = QHostAddress("239.255.43.21"); udpSocket->joinMulticastGroup(groupAddress); 发送与接收 必须是相同的组 */ //IP地址列表 ui->comboBox->clear(); //本机IP地址 #if 0 QHostInfo hostInfo = QHostInfo::fromName(hostName); QList<QHostAddress> addrList = hostInfo.addresses(); for(int i = 0; i < addrList.count(); i++) { QHostAddress host = addrList.at(i); if(QAbstractSocket::IPv4Protocol == host.protocol()) { QString ip = host.toString(); ui->comboBox->addItem(ip); } } #endif ui->comboBox->addItem("239.255.255.250"); ui->comboBox->addItem("239.255.43.21"); } MainWindow::~MainWindow() { delete ui; } void MainWindow::on_btnClear_clicked() { ui->plainTextEdit->clear(); } void MainWindow::on_btnSend_clicked()//组播 { //目标端口 quint16 groupPort = ui->spinBindPort->value(); QString msg = ui->lineEdit->text(); QByteArray str = msg.toUtf8(); QString IP = ui->comboBox->currentText(); groupAddr = QHostAddress(IP); qDebug() << "Group Address" << groupAddr ;//groupAddr = QHostAddress("239.255.43.21"); //发出数据报 m_udpSocket->writeDatagram(str, groupAddr, groupPort); ui->plainTextEdit->appendPlainText("[multicast] " + msg); } void MainWindow::on_readyRead() { while(m_udpSocket->hasPendingDatagrams()) { QByteArray data; data.resize(m_udpSocket->pendingDatagramSize()); QHostAddress peerAddr; quint16 peerPort; m_udpSocket->readDatagram(data.data(), data.size(), &peerAddr, &peerPort); QString str = data.data(); QString peer = "[From ] +" + peerAddr.toString() + ":" + QString::number(peerPort) + "] "; ui->plainTextEdit->appendPlainText(peer + str); } } void MainWindow::on_btnJoin_clicked() { QString IP = ui->comboBox->currentText(); groupAddr = QHostAddress(IP); qDebug() << "Group Address" << groupAddr ;//groupAddr = QHostAddress("239.255.43.21"); quint16 groupPort = ui->spinBindPort->value(); //加入组播之前，必须先绑定端口，端口为多播组统一的一个端口。 if(m_udpSocket->bind(QHostAddress::AnyIPv4, groupPort, QUdpSocket::ShareAddress)) { //加入组播 m_udpSocket->joinMulticastGroup(groupAddr); ui->plainTextEdit->appendPlainText("**加入组播成功"); ui->plainTextEdit->appendPlainText("**组播IP: " + IP); ui->plainTextEdit->appendPlainText("**绑定端口: " + QString::number(groupPort)); ui->btnJoin->setEnabled(false); ui->btnExit->setEnabled(true); ui->comboBox->setEnabled(false); } else { ui->plainTextEdit->appendPlainText("**绑定端口失败"); } } void MainWindow::on_btnExit_clicked() { //退出组播 m_udpSocket->leaveMulticastGroup(groupAddr); //解除绑定 m_udpSocket->abort(); ui->btnJoin->setEnabled(true); ui->btnExit->setEnabled(false); ui->comboBox->setEnabled(true); ui->plainTextEdit->appendPlainText("**已退出组播"); }