请使用QT建立TCP通信的服务端程序和客户端程序

在Qt中，可以利用其强大的跨平台网络编程库QTcpServer和QTcpClient来创建TCP通信服务端和客户端程序。这里是一个简单的步骤指南：

**服务端程序（server.cpp）：**

#include <QObject>
#include <QTcpServer>

class Server : public QObject
{
    Q_OBJECT

public:
    explicit Server(QObject *parent = nullptr)
        : QObject(parent), server(new QTcpServer(this))
    {
        if (server->listen(QHostAddress::Any, 8000)) { // 默认端口8000
            emit started();
            qInfo() << "Server is listening on port 8000.";
        } else {
            qCritical() << "Failed to start the server: " << server->errorString();
        }
    }

signals:
    void started();

public slots:
    void incomingConnection(int socketDescriptor)
    {
        QByteArray clientAddress = server->peerAddress().toString();
        qInfo() << "New connection from:" << clientAddress;

        QTcpSocket *client = new QTcpSocket(this);
        connect(client, &QTcpSocket::disconnected, this, &Server::removeClient);
        client->setSocketDescriptor(socketDescriptor);

        client->write("Welcome to the TCP server!");
    }

private:
    QTcpServer *server;
};

int main(int argc, char *argv[])
{
    QApplication app(argc, argv);

    Server server;
    QObject::connect(&app, &QApplication::aboutToQuit, &server, &Server::deleteLater);
    return app.exec();
}

**客户端程序（client.cpp）：**

#include <QObject>
#include <QTcpSocket>

class Client : public QObject
{
    Q_OBJECT

public:
    explicit Client(const QString &host, int port, QObject *parent = nullptr)
        : QObject(parent), socket(new QTcpSocket(this))
    {
        connect(socket, &QTcpSocket::readyRead, this, &Client::handleData);
        if (!socket->connectToHost(host, port)) {
            qCritical() << "Failed to connect to server: " << socket->errorString();
            return;
        }
        emit connected();
    }

signals:
    void connected();

public slots:
    void sendData()
    {
        QByteArray message = "Hello, Server!";
        socket->write(message);
    }

private slots:
    void handleData()
    {
        QByteArray data = socket->readAll();
        qDebug() << "Received from server: " << data.data();
    }

private:
    QTcpSocket *socket;
};

int main(int argc, char *argv[])
{
    QApplication app(argc, argv);

    Client client(QStringLiteral("localhost"), 8000); // 使用本地主机名和默认端口
    QObject::connect(&app, &QApplication::aboutToQuit, &client, &Client::deleteLater);
    client.sendData(); // 发送数据
    return app.exec();
}