用QT写一个网络通信类，用于接收和发送QByteArray数据

在Qt中，你可以使用QTcpSocket或QUdpSocket来处理TCP或UDP网络通信。以下是一个简单的例子，展示了如何创建一个基础的网络通信类，用于接收和发送`QByteArray`数据：

#include <QObject>
#include <QHostAddress>
#include <QTcpSocket>
#include <QByteArray>

class NetworkCommunicator : public QObject
{
    Q_OBJECT

public:
    explicit NetworkCommunicator(QHostAddress address, quint16 port, QObject *parent = nullptr)
        : QObject(parent), socket(address, Qt::DirectConnection, port)
    {
        connect(&socket, &QTcpSocket::connected, this, &NetworkCommunicator::connected);
        connect(&socket, &QTcpSocket::readyRead, this, &NetworkCommunicator::readData);
        connect(&socket, &QTcpSocket::disconnected, this, &NetworkCommunicator::disconnected);
    }

    ~NetworkCommunicator()
    {
        if (isConnected())
            disconnectFromHost();
    }

    void sendData(QByteArray data)
    {
        if (!socket.isOpen()) {
            qDebug() << "Socket is not open. Opening...";
            socket.open(QIODevice::WriteOnly);
            if (!socket.waitForConnected(5000)) {
                qWarning() << "Failed to connect";
                return;
            }
        }

        qint64 bytesWritten = socket.write(data);
        if (bytesWritten == -1) {
            qWarning() << "Failed to write data";
        } else {
            qDebug() << "Sent" << bytesWritten << "bytes";
        }
    }

    QByteArray receiveData()
    {
        if (!socket.bytesAvailable()) {
            qDebug() << "No data available";
            return QByteArray();
        }

        QByteArray receivedData;
        qint64 bytesRead = socket.read(receivedData);
        if (bytesRead > 0) {
            qDebug() << "Received" << bytesRead << "bytes";
            return receivedData;
        } else {
            qWarning() << "Failed to read data";
        }
        return QByteArray();
    }

signals:
    void connectionEstablished();
    void dataReceived(QByteArray data);

private slots:
    void connected()
    {
        emit connectionEstablished();
    }

    void disconnected()
    {
        emit dataReceived(QByteArray());
    }

private:
    QTcpSocket socket;
    bool isConnected() const { return socket.state() == SocketState::Open; }

    // Disconnection method
    void disconnectFromHost()
    {
        socket.disconnectFromHost();
    }
};

这个`NetworkCommunicator`类接受一个IP地址、端口作为参数，并维护一个`QTcpSocket`实例。它提供了`sendData`和`receiveData`方法用于传输数据。当连接建立时，会发出`connectionEstablished`信号；当接收到数据时，会发出`dataReceived`信号。

要使用这个类，你需要创建一个实例并连接到所需的服务器：

NetworkCommunicator communicator("127.0.0.1", 12345);
connect(&communicator, &NetworkCommunicator::dataReceived, yourReceiverObject, &YourReceiverClass::handleDataReceived);