用qt写一段socket代理层的代码实现两个上位机同时连接两个下位机，并将两个下位机的数据呈现在上位机上

下面是一个用Qt编写的简单的Socket代理层的代码，实现两个上位机同时连接两个下位机，并将两个下位机的数据呈现在上位机上。假设下位机的地址分别为192.168.1.100和192.168.1.200，端口号为6666和7777。

#include <QtNetwork>
#include <QTcpSocket>

class Proxy : public QObject
{
    Q_OBJECT
public:
    explicit Proxy(QObject *parent = nullptr)
        : QObject(parent)
        , m_server1(new QTcpServer(this))
        , m_server2(new QTcpServer(this))
    {
        connect(m_server1, &QTcpServer::newConnection, this, &Proxy::onNewConnection1);
        connect(m_server2, &QTcpServer::newConnection, this, &Proxy::onNewConnection2);

        if (!m_server1->listen(QHostAddress::Any, 6666)) {
            qDebug() << "Server1 listen failed";
        }

        if (!m_server2->listen(QHostAddress::Any, 7777)) {
            qDebug() << "Server2 listen failed";
        }
    }

private slots:
    void onReadyRead1()
    {
        QTcpSocket *socket = qobject_cast<QTcpSocket*>(sender());
        if (!socket) {
            return;
        }

        QTcpSocket *peer = m_peers.value(socket);
        if (!peer) {
            return;
        }

        QByteArray data = socket->readAll();
        peer->write(data);
    }

    void onReadyRead2()
    {
        QTcpSocket *socket = qobject_cast<QTcpSocket*>(sender());
        if (!socket) {
            return;
        }

        QTcpSocket *peer = m_peers.value(socket);
        if (!peer) {
            return;
        }

        QByteArray data = socket->readAll();
        peer->write(data);
    }

    void onNewConnection1()
    {
        QTcpSocket *socket = m_server1->nextPendingConnection();
        if (!socket) {
            return;
        }

        QTcpSocket *peer = new QTcpSocket(this);
        peer->connectToHost(QHostAddress("192.168.1.100"), 6666);
        if (!peer->waitForConnected()) {
            qDebug() << "Connect to server1 failed";
            socket->disconnectFromHost();
            socket->deleteLater();
            return;
        }

        m_peers.insert(socket, peer);
        m_peers.insert(peer, socket);

        connect(socket, &QTcpSocket::readyRead, this, &Proxy::onReadyRead1);
        connect(peer, &QTcpSocket::readyRead, this, &Proxy::onReadyRead1);
        connect(socket, &QTcpSocket::disconnected, this, &Proxy::onDisconnected);
        connect(peer, &QTcpSocket::disconnected, this, &Proxy::onDisconnected);
    }

    void onNewConnection2()
    {
        QTcpSocket *socket = m_server2->nextPendingConnection();
        if (!socket) {
            return;
        }

        QTcpSocket *peer = new QTcpSocket(this);
        peer->connectToHost(QHostAddress("192.168.1.200"), 7777);
        if (!peer->waitForConnected()) {
            qDebug() << "Connect to server2 failed";
            socket->disconnectFromHost();
            socket->deleteLater();
            return;
        }

        m_peers.insert(socket, peer);
        m_peers.insert(peer, socket);

        connect(socket, &QTcpSocket::readyRead, this, &Proxy::onReadyRead2);
        connect(peer, &QTcpSocket::readyRead, this, &Proxy::onReadyRead2);
        connect(socket, &QTcpSocket::disconnected, this, &Proxy::onDisconnected);
        connect(peer, &QTcpSocket::disconnected, this, &Proxy::onDisconnected);
    }

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

        QTcpSocket *peer = m_peers.value(socket);
        if (!peer) {
            return;
        }

        m_peers.remove(socket);
        m_peers.remove(peer);

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

private:
    QTcpServer *m_server1;
    QTcpServer *m_server2;
    QHash<QTcpSocket*, QTcpSocket*> m_peers;
};

这个代码中，我们创建了一个`Proxy`类，用来处理两个上位机和两个下位机之间的通信。在构造函数中，我们创建了两个`QTcpServer`对象来监听两个不同的端口。当有新的连接到来时，我们会创建一个新的`QTcpSocket`对象来处理连接。然后，我们会尝试连接到下位机的地址和端口号。如果连接成功，我们会将两个`QTcpSocket`对象存储到一个哈希表中，以便在数据传输时使用。我们还连接了两个上位机和两个下位机的`readyRead`和`disconnected`信号，以便在需要时处理数据和连接断开。