QTcpServer服务端问题记录

在开发Qt  socket通讯的服务端时遇到一些问题，记录下来。

1.对服务端的处理有 2种情况，

   第一种情况是在一个普通类里 new QTcpServer(); 关联newConnection信号，在相应的槽里用nextPendingConnection接收，注意，不是new QTcpSocket

接收客户端的连接

#include <QObject>

#include <QTcpServer>

#include <QTcpSocket>

class AppWork : public QObject

{

    Q_OBJECT

public:

    explicit AppWork(QObject *parent = nullptr);

    void DoWork();

signals:

public slots:

    void OnNewConnection();

    void OnClientConnected();

    void OnClientDisConnected();

    void OnReadClientData();

    void OnStateChanged(QAbstractSocket::SocketState);

private:

    QTcpServer *m_pServer;

    QTcpSocket *m_pSocket;

void AppWork::DoWork()

{

    m_pServer = new QTcpServer();

    connect(m_pServer,SIGNAL(newConnection()),this,SLOT(OnNewConnection()));

    m_pServer->listen(QHostAddress::Any,6000);

}

void AppWork::OnNewConnection()

{

    qDebug()<<"Received A New Connect";

    //m_pSocket = new QTcpSocket();不是new tcpsocket,而是用nextPendingConnection接收

    m_pSocket = m_pServer->nextPendingConnection();

    //connect(m_pSocket,SIGNAL(connected()),this,SLOT(OnClientConnected())); connectToHost()才会触发，这里不会触发

    connect(m_pSocket,SIGNAL(disconnected()),this,SLOT(OnClientDisConnected()));

    connect(m_pSocket,SIGNAL(readyRead()),this,SLOT(OnReadClientData()));

    connect(m_pSocket,SIGNAL(stateChanged(QAbstractSocket::SocketState)),this,SLOT(OnStateChanged(QAbstractSocket::SocketState)));

    m_pSocket->write("Hello Client,This is Server");

}



第2种方式是继承QTceServer, 重载incommingConnection
#include <QObject>

#include <QTcpServer>

#include <QTcpSocket>

class DTServer : public QTcpServer

{

public:

    DTServer();

    void incomingConnection(qintptr handle);

public slots:

    void OnDataReceive();

private:

    QTcpSocket *m_pSocket;

};

DTServer::DTServer()

{

}

void DTServer::incomingConnection(qintptr handle)

{

    qDebug()<<"Incomming Connect...";

    m_pSocket  = new QTcpSocket();

    m_pSocket->setSocketDescriptor(handle);

     //QObject::connect: No such slot QTcpServer::OnDataReceive() in ..\DTServer\dtserver.cpp:15  --》是由于 这个DTServer类忘了写Q_OBJECT了。所以识别不出来槽，需要把文 件重新移除，再添加进来

    //connect(m_pSocket,SIGNAL(readyRead()),this,SLOT(OnDataReceive()));// 注意，这里 this的定法 运行起来，当有连接到来 会提示 没有槽函数，为什么呢？子类也实现了，非要找基类去。然后说 没有

    connect(m_pSocket,&QTcpSocket::readyRead,this,&DTServer::OnDataReceive);//下面这种写法可以

    m_pSocket->write("Hello");

}

 



总结一下
第一种：处理newConnection信号，在相应的槽里m_pServer->nextPendingConnection() 获了与客户端的连接后即可进行通讯了
第二种：incomingConnection 里需要new  QTcpSocket，再setSocketDescriptor 就可以进行通讯了