用qt写一个udp收发的自定义报文协议

下面是一个用 Qt 写的 UDP 收发自定义报文协议的示例代码：

#include <QtNetwork/QUdpSocket>

struct MyPacket {
    quint16 id;
    quint8 type;
    QByteArray data;
};

class MyUdpProtocol : public QObject {
    Q_OBJECT

public:
    explicit MyUdpProtocol(QObject *parent = nullptr)
        : QObject(parent), socket(new QUdpSocket(this))
    {
        connect(socket, &QUdpSocket::readyRead, this, &MyUdpProtocol::onReadyRead);
    }

    bool bind(quint16 port)
    {
        return socket->bind(QHostAddress::Any, port);
    }

    void sendPacket(const MyPacket &packet, const QHostAddress &address, quint16 port)
    {
        QByteArray datagram;
        QDataStream out(&datagram, QIODevice::WriteOnly);
        out << packet.id << packet.type << packet.data;
        socket->writeDatagram(datagram, address, port);
    }

signals:
    void packetReceived(const MyPacket &packet, const QHostAddress &sender, quint16 senderPort);

private slots:
    void onReadyRead()
    {
        while (socket->hasPendingDatagrams()) {
            QByteArray datagram;
            datagram.resize(socket->pendingDatagramSize());
            QHostAddress sender;
            quint16 senderPort;
            if (socket->readDatagram(datagram.data(), datagram.size(), &sender, &senderPort) == -1) {
                continue;
            }
            QDataStream in(datagram);
            MyPacket packet;
            in >> packet.id >> packet.type >> packet.data;
            emit packetReceived(packet, sender, senderPort);
        }
    }

private:
    QUdpSocket *socket;
};

你可以根据自己的需求修改 `MyPacket` 的成员变量，然后在 `sendPacket` 和 `packetReceived` 中处理自定义的报文协议。使用方法示例：

MyUdpProtocol protocol;
protocol.bind(1234);
connect(&protocol, &MyUdpProtocol::packetReceived, [](const MyPacket &packet, const QHostAddress &sender, quint16 senderPort) {
    qDebug() << "Received packet from" << sender.toString() << senderPort << ": ID=" << packet.id << ", Type=" << packet.type << ", Data=" << packet.data;
});
MyPacket packet = { 1234, 1, QByteArray("Hello, World!") };
protocol.sendPacket(packet, QHostAddress::LocalHost, 1234);