QT实现一个多人聊天系统客户端和服务端代码

以下是一个基于QT的多人聊天系统客户端和服务端的示例代码：

服务端代码：

#include <QtNetwork/QTcpServer>
#include <QtNetwork/QTcpSocket>
#include <QVector>

int main(int argc, char *argv[])
{
    QTcpServer server;
    QVector<QTcpSocket*> clients;

    QObject::connect(&server, &QTcpServer::newConnection, [&](){
        QTcpSocket* client = server.nextPendingConnection();
        clients.append(client);

        QObject::connect(client, &QTcpSocket::readyRead, [=](){
            QByteArray data = client->readAll();
            for(QTcpSocket* otherClient : clients)
            {
                if(otherClient != client)
                    otherClient->write(data);
            }
        });

        QObject::connect(client, &QTcpSocket::disconnected, [=](){
            clients.removeOne(client);
            client->deleteLater();
        });
    });

    if(server.listen(QHostAddress::Any, 1234))
        qDebug() << "Server started";
    else
        qDebug() << "Server failed to start";

    return 0;
}

客户端代码：

#include <QtNetwork/QTcpSocket>

int main(int argc, char *argv[])
{
    QTcpSocket socket;
    socket.connectToHost("127.0.0.1", 1234);

    QObject::connect(&socket, &QTcpSocket::readyRead, [&](){
        QByteArray data = socket.readAll();
        qDebug() << data;
    });

    QTextStream stream(stdin);
    while(true)
    {
        QString message = stream.readLine();
        socket.write(message.toUtf8());
    }

    return 0;
}

这个示例代码比较简单，服务端只是简单地把接收到的消息广播给所有连接的客户端，而客户端只是简单地从标准输入读取消息并发送给服务端，然后从服务端接收消息并输出到控制台。在实际的应用中，还需要考虑很多其他的问题，比如消息的格式、用户登录、用户列表、私聊等等。