qt tcp 服务器多线程与多个客户端通信

在Qt中，可以通过QTcpServer类来实现TCP服务器的编写，而多线程则可以通过QThread类来实现。下面是一个简单的示例程序，可以实现多线程与多个客户端的通信：

#include <QtNetwork>
#include <QtWidgets>
#include <QtCore>

class ClientThread : public QThread
{
    Q_OBJECT

public:
    explicit ClientThread(qintptr socketDescriptor, QObject *parent = nullptr)
        : QThread(parent), m_socketDescriptor(socketDescriptor)
    {
    }

signals:
    void error(QTcpSocket::SocketError socketError);

protected:
    void run() override
    {
        QTcpSocket socket;
        if (!socket.setSocketDescriptor(m_socketDescriptor)) {
            emit error(socket.error());
            return;
        }

        connect(&socket, &QTcpSocket::readyRead, this, &ClientThread::readyRead);
        connect(&socket, &QTcpSocket::disconnected, this, &ClientThread::disconnected);

        exec();
    }

private slots:
    void readyRead()
    {
        QTcpSocket *socket = qobject_cast<QTcpSocket *>(sender());
        if (!socket)
            return;

        QByteArray data = socket->readAll();
        // 处理接收到的数据

        socket->flush();
    }

    void disconnected()
    {
        QTcpSocket *socket = qobject_cast<QTcpSocket *>(sender());
        if (!socket)
            return;

        socket->deleteLater();
        quit();
    }

private:
    qintptr m_socketDescriptor;
};

class TcpServer : public QTcpServer
{
    Q_OBJECT

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

protected:
    void incomingConnection(qintptr socketDescriptor) override
    {
        ClientThread *thread = new ClientThread(socketDescriptor, this);
        connect(thread, &ClientThread::finished, thread, &ClientThread::deleteLater);
        thread->start();
    }
};

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

    TcpServer server;
    if (!server.listen(QHostAddress::Any, 1234)) {
        qCritical() << "Failed to start server:" << server.errorString();
        return 1;
    }

    qDebug() << "Server started:" << server.serverAddress().toString() << server.serverPort();

    return app.exec();
}

#include "main.moc"

在这个示例程序中，TcpServer类继承自QTcpServer类，其中的incomingConnection()函数会在新的客户端连接时被调用。在该函数中，我们创建一个新的ClientThread线程，并将客户端的socket描述符传递给它。在ClientThread线程中，我们可以通过QTcpSocket类来与客户端进行通信。当客户端连接断开时，我们需要清理socket并退出线程。

需要注意的是，由于Qt的对象树模型，我们需要在ClientThread线程中使用deleteLater()函数来删除socket对象。这可以确保socket对象不会在其所属的线程销毁之前被销毁。