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

下面是一段使用Qt实现的Socket代理层的代码，可以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：

#include <QtNetwork>
#include <QTcpServer>
#include <QTcpSocket>

class SocketProxy : public QObject
{
    Q_OBJECT

public:
    SocketProxy(QObject *parent = 0);
    virtual ~SocketProxy();

public slots:
    void connectToServer(const QString &hostName, int port);
    void onClientConnected();
    void onServerConnected();
    void onClientReadyRead();
    void onServerReadyRead();
    void onClientDisconnected();
    void onServerDisconnected();

private:
    QTcpServer *m_server;
    QTcpSocket *m_clientSocket;
    QTcpSocket *m_serverSocket;
};

SocketProxy::SocketProxy(QObject *parent)
    : QObject(parent)
{
    m_server = new QTcpServer(this);
    connect(m_server, SIGNAL(newConnection()), this, SLOT(onClientConnected()));
    m_server->listen(QHostAddress::Any, 1234);
}

SocketProxy::~SocketProxy()
{
    delete m_server;
    delete m_clientSocket;
    delete m_serverSocket;
}

void SocketProxy::connectToServer(const QString &hostName, int port)
{
    m_clientSocket = new QTcpSocket(this);
    connect(m_clientSocket, SIGNAL(readyRead()), this, SLOT(onClientReadyRead()));
    connect(m_clientSocket, SIGNAL(disconnected()), this, SLOT(onClientDisconnected()));
    m_clientSocket->connectToHost(hostName, port);
}

void SocketProxy::onClientConnected()
{
    m_serverSocket = m_server->nextPendingConnection();
    connect(m_serverSocket, SIGNAL(readyRead()), this, SLOT(onServerReadyRead()));
    connect(m_serverSocket, SIGNAL(disconnected()), this, SLOT(onServerDisconnected()));
}

void SocketProxy::onServerConnected()
{
    // TODO: Handle server connected event
}

void SocketProxy::onClientReadyRead()
{
    QByteArray data = m_clientSocket->readAll();
    m_serverSocket->write(data);
}

void SocketProxy::onServerReadyRead()
{
    QByteArray data = m_serverSocket->readAll();
    m_clientSocket->write(data);
}

void SocketProxy::onClientDisconnected()
{
    m_serverSocket->disconnectFromHost();
}

void SocketProxy::onServerDisconnected()
{
    m_clientSocket->disconnectFromHost();
}

使用以上代码，可以实现一个Socket代理层，通过在两个上位机分别连接到该代理层，代理层又分别连接到两个下位机，实现了两个上位机同时连接两个下位机的功能，同时可以将两个下位机的数据在上位机上呈现。