用qt写一个简单关于TcpProxy的例子

好的，下面是一个简单的基于Qt的TcpProxy的例子：

#include <QtNetwork>

class TcpProxy : public QObject
{
    Q_OBJECT

public:
    TcpProxy(QObject *parent = nullptr) : QObject(parent)
    {
        m_server = new QTcpServer(this);
        connect(m_server, &QTcpServer::newConnection, this, &TcpProxy::onNewConnection);
        if (!m_server->listen(QHostAddress::Any, 8888)) {
            qDebug() << "Error: " << m_server->errorString();
        } else {
            qDebug() << "TcpProxy is listening on port 8888";
        }
    }

private slots:
    void onNewConnection()
    {
        QTcpSocket *clientSocket = m_server->nextPendingConnection();
        QTcpSocket *serverSocket = new QTcpSocket(this);
        m_clientSockets.append(clientSocket);
        m_serverSockets.append(serverSocket);

        connect(clientSocket, &QTcpSocket::readyRead, this, &TcpProxy::onClientReadyRead);
        connect(clientSocket, &QTcpSocket::disconnected, this, &TcpProxy::onClientDisconnected);

        connect(serverSocket, &QTcpSocket::connected, this, &TcpProxy::onServerConnected);
        connect(serverSocket, &QTcpSocket::disconnected, this, &TcpProxy::onServerDisconnected);
        connect(serverSocket, &QTcpSocket::readyRead, this, &TcpProxy::onServerReadyRead);

        serverSocket->connectToHost("localhost", 80);
    }

    void onClientReadyRead()
    {
        QTcpSocket *clientSocket = qobject_cast<QTcpSocket*>(sender());
        QTcpSocket *serverSocket = m_serverSockets.at(m_clientSockets.indexOf(clientSocket));

        QByteArray data = clientSocket->readAll();
        serverSocket->write(data);
    }

    void onClientDisconnected()
    {
        QTcpSocket *clientSocket = qobject_cast<QTcpSocket*>(sender());
        QTcpSocket *serverSocket = m_serverSockets.at(m_clientSockets.indexOf(clientSocket));

        m_clientSockets.removeOne(clientSocket);
        m_serverSockets.removeOne(serverSocket);

        clientSocket->deleteLater();
        serverSocket->deleteLater();
    }

    void onServerConnected()
    {
        qDebug() << "Server connected";
    }

    void onServerDisconnected()
    {
        qDebug() << "Server disconnected";
    }

    void onServerReadyRead()
    {
        QTcpSocket *serverSocket = qobject_cast<QTcpSocket*>(sender());
        QTcpSocket *clientSocket = m_clientSockets.at(m_serverSockets.indexOf(serverSocket));

        QByteArray data = serverSocket->readAll();
        clientSocket->write(data);
    }

private:
    QTcpServer *m_server;
    QList<QTcpSocket*> m_clientSockets;
    QList<QTcpSocket*> m_serverSockets;
};

这个例子是一个简单的TCP代理服务器。它监听本地8888端口，当客户端连接时，它会连接到远程服务器（这里是localhost:80），并将客户端数据转发到远程服务器，反之亦然。示例中使用了QTcpServer和QTcpSocket，通过connect函数将信号和槽连接起来，实现了基本的TCP代理功能。