用qt写一个 tcp服务器修改客户端的port的示例程序

好的，以下是示例代码：

#include <QTcpServer>
#include <QTcpSocket>

// 自定义信号槽，用于客户端连接成功时处理
class Server : public QTcpServer {
    Q_OBJECT

public:
    explicit Server(QObject* parent = nullptr) : QTcpServer(parent) {}

signals:
    void clientConnected(QTcpSocket*);

protected:
    void incomingConnection(qintptr socketDescriptor) override {
        QTcpSocket* clientSocket = new QTcpSocket(this);
        clientSocket->setSocketDescriptor(socketDescriptor);
        emit clientConnected(clientSocket);
    }
};

// 客户端
class Client : public QObject {
    Q_OBJECT

public:
    explicit Client(QObject* parent = nullptr) : QObject(parent) {}

    void connectToServer(const QString& hostName, quint16 port) {
        m_socket.connectToHost(hostName, port);
    }

    bool isConnected() const {
        return m_socket.state() == QAbstractSocket::ConnectedState;
    }

    void changePort(quint16 port) {
        m_socket.write(QString::number(port).toUtf8());
        m_socket.flush();
    }

private:
    QTcpSocket m_socket;
};

#include <QCoreApplication>

int main(int argc, char* argv[]) {
    QCoreApplication a(argc, argv);

    Server server;
    Client client;

    // 当有客户端连接时，处理如下逻辑
    QObject::connect(&server, &Server::clientConnected, &client, [&](QTcpSocket* clientSocket) {
        // 连接成功，修改端口为8888
        client.connectToServer("localhost", 8888);
        while (!client.isConnected()) {
            // 等待连接成功
            qApp->processEvents();
        }
        client.changePort(9999);
        // 操作完成，断开连接
        clientSocket->close();
        delete clientSocket;
    });

    // 启动服务器，监听端口8888
    server.listen(QHostAddress::Any, 8888);

    return a.exec();
}

注意：以上示例仅供演示/学习用途，实际开发中需考虑更多因素，如错误处理、协议设计等。