qt tcp socket 通信实例

Qt TCP套接字通信实例通常用于客户端和服务器之间的双向数据传输，例如聊天应用、游戏服务器等。以下是使用Qt C++的一个简单示例：

首先，你需要包含必要的头文件并设置基本的TCP服务器：

#include <QObject>
#include <QTcpServer>
#include <QTcpSocket>

class Server : public QObject
{
    Q_OBJECT
public slots:
    void startServer() {
        QTcpServer *server = new QTcpServer(this);
        if (server->listen(QHostAddress::Any, 8080)) { // 监听所有地址的8080端口
            while (!server->isListening()) { // 当服务器开始监听时
                qApp->processEvents(); // 保持应用程序活跃
            }
            connect(server, &QTcpServer::newConnection, this, &Server::handleNewConnection); // 连接到新连接事件
            qDebug() << "Server is listening on port 8080";
        } else {
            qDebug() << "Failed to listen on port 8080";
        }
    }

private slots:
    void handleNewConnection() {
        QTcpSocket *socket = server->nextPendingConnection();
        connect(socket, &QTcpSocket::readyRead, this, &Server::handleDataReceived);
        connect(socket, &QObject::destroyed, this, &Server::removeSocket);
    }

    void handleDataReceived() {
        QByteArray data = socket->readAll();
        emit sendDataToClient(data); // 发送给处理数据的部分
    }

    void removeSocket(QObject *sender) {
        delete sender; // 删除已断开的连接
    }
};

然后，你可以创建一个`Client`类，进行相应的TCP连接请求：

class Client : public QObject
{
    Q_OBJECT

public:
    explicit Client(QObject *parent = nullptr) : QObject(parent), socket(new QTcpSocket(this)) {}

public slots:
    void connectToServer(const QString &host, quint16 port) {
        socket->connectToHost(host, port);
        connect(socket, &QTcpSocket::connected, this, &Client::sendHelloMessage);
        connect(socket, &QTcpSocket::error, this, &Client::connectionError);
    }

private slots:
    void sendHelloMessage() {
        socket->write("Hello from client!"); // 发送一条消息到服务器
    }

    void connectionError() {
        qDebug() << "Connection error";
    }

signals:
    void receiveDataFromServer(const QByteArray &data); // 信号发射接收的数据

protected:
    QTcpSocket *socket;
};

要在客户端和服务器之间传递数据，需要在`Server`类中添加信号处理器，并在`Client`类中对接收的信号作出响应：

void Server::sendDataToClient(const QByteArray &data) {
    emit sendDataToClient(data); // 发送给客户端的信号
}

void Client::receiveDataFromServer(const QByteArray &data) {
    qDebug() << "Received message: " << data.toUtf8().constData();
}

最后，在主程序中初始化服务器和客户端：

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

    Server server;
    connect(&app, &QApplication::aboutToQuit, &server, &Server::quit); // 关闭服务器时关闭应用
    server.startServer();

    Client client;
    client.connectToServer("localhost", 8080); // 如果是本地测试，主机名通常为"localhost"

    return app.exec();
}