QT 网络笔记

我会带着你远行 2022-06-16 14:23 233阅读 0赞

QT网络编程

1. QTcpServer 是一个监听socket

(1 ) 调用 listen() 监听连接.

(2) 当有新客户链接请求时，会发送newConnection() 信号

(3) 调用nextPendingConnection() 接受链接请求，该函数返回一个 QTcpSocket.指针，可用该SOCKET与客户通信.

2. QTcpSocket 用来发送接收数据

Inherits: QAbstractSocket.

（1）调用connectToHost连接到服务器

（2）当连接成功后，会发送:connected () \[signal\]，可调用write()以发送数据

（3） 当有新数据大道时，会触发readyRead() 信号，可调用 read()读数据

3. 跨线程调用

QTcpServer 调用nextPendingConnection() 返回的QTcpSocket 不能再另一线程中使用，如果要使用，必须重写 incomingConnection().

见QT自带例子 fortunethread:

class FortuneServer: publicQTcpServer  
\{  
    Q\_OBJECT  
  //....  
protected:  
    void incomingConnection(int socketDescriptor);  
\};  
   
void FortuneServer::incomingConnection(int socketDescriptor)  
\{  
  QString fortune = fortunes.at(qrand() % fortunes.size());  
 FortuneThread \*thread = new FortuneThread(socketDescriptor, fortune, this);  
  connect(thread, SIGNAL(finished()), thread, SLOT(deleteLater()));  
 thread->start();  
\}  
\-------------------------------------------------------------------  
class FortuneThread : public QThread  
\{     
Q\_OBJECTpublic:        void run();  
//....略  
\};

void FortuneThread::run()  
\{

QTcpSocket tcpSocket;  
    if (!tcpSocket.setSocketDescriptor(socketDescriptor))  
      \{   
        emit error(tcpSocket.error());     
       return;  
      \}  
    QByteArray block;   
   //....     
   tcpSocket.write(block);    
   tcpSocket.disconnectFromHost();     
  tcpSocket.waitForDisconnected();  
\}

详细请参考QT助手

void QTcpServer::incomingConnection ( int socketDescriptor ) \[virtual protected\]  
     Note: If you want to handle an incoming connection as a new QTcpSocket object in another thread you have to pass the socketDescriptor to the other thread and create the QTcpSocket object there and use its setSocketDescriptor() method.