QT 线程池 + TCP 小试（二）实现通信功能

*免分资源链接点击打开链接http://download.csdn.net/detail/goldenhawking/4492378

有了线程池，我们下一步就利用 QTcpServer 搭建一个服务器，接受客户端的连接，并把数据发送到线程池上。由于 QTcpServer 资料太多了，这里不在赘述。唯一值得注意的是，当客户端退出时，如果线程池队列中还有该客户的信息，这个信息还会被处理，只是无法再发送回去而已。其实，还可实现成客户端退出，就发一个信号到线程池，删除自己的所有任务。这个也很简单，但之所以没有做，因为这些数据的处理结果可能还会被其他消费者（而非生产者自己）使用，最典型的例子是从工业传感器上采集的数据，其生成的图像需要存储到设备中去。

QTcpSocket的 Write 方法默认是支持大体积数据的，即使一次发了500MB的数据，只要硬件资源可以承受，调用也会成功并立刻返回。接受者会以一定的载荷大小不停的触发readyRead，直到发送全部成功。但是，为了能够观察到并控制收发队列中的数据包的大小、体积，我们在外层实现了一个发送队列，每次以 payLoad为大小发送数据包。这是从MFC中带来的习惯，很难说好坏。

qghtcpserver.h

[cpp]
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#ifndef QGHTCPSERVER_H
#define QGHTCPSERVER_H

#include <QTcpServer>
#include <QMap>
#include <QList>

class QGHTcpServer : public QTcpServer
{
Q_OBJECT

public:
QGHTcpServer(QObject *parent,int nPayLoad = 4096);
~QGHTcpServer();
//踢出所有客户
void KickAllClients();
QList <QObject *> clientsList();
void SetPayload(int nPayload);
private:
QMap<QObject *,QList<QByteArray> > m_buffer_sending;
QMap<QObject *,QList<qint64> > m_buffer_sending_offset;
QMap<QObject*,int> m_clientList;
int m_nPayLoad;
public slots:
//新的客户连接到来
void new_client_recieved();
//客户连接被关闭
void client_closed();
//新的数据到来
void new_data_recieved();
//一批数据发送完毕
void some_data_sended(qint64);
//客户端错误
void displayError(QAbstractSocket::SocketError socketError);
//向客户端发送数据
void SendDataToClient(QObject * objClient,const QByteArray & dtarray);
//向客户端广播数据，不包括 objFromClient
void BroadcastData(QObject * objFromClient,const QByteArray & dtarray);
signals:
//错误信息
void evt_SocketError(QObject * senderSock ,QAbstractSocket::SocketError socketError);
//新的客户端连接
void evt_NewClientConnected(QObject * client);
//客户端退出
void evt_ClientDisconnected(QObject * client);
//收到一批数据
void evt_Data_recieved(QObject * ,const QByteArray & );
//一批数据被发送
void evt_Data_transferred(QObject * client,qint64);
};

#endif // QGHTCPSERVER_H

qghtcpserver.cpp

[cpp]
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#include "qghtcpserver.h"
#include <assert.h>
#include <QTcpSocket>
QGHTcpServer::QGHTcpServer(QObject *parent,int nPayLoad )
: QTcpServer(parent),
m_nPayLoad(nPayLoad)
{
assert(m_nPayLoad>=256 && m_nPayLoad<=16*1024*1024);
connect(this, SIGNAL(newConnection()), this, SLOT(new_client_recieved()));
}

QGHTcpServer::~QGHTcpServer()
{

}
QList <QObject *> QGHTcpServer::clientsList()
{
return m_clientList.keys();
}
void QGHTcpServer::SetPayload(int nPayload)
{
m_nPayLoad = nPayload;
assert(m_nPayLoad>=256 && m_nPayLoad<=16*1024*1024);
}

void QGHTcpServer::new_client_recieved()
{
QTcpSocket * sock_client = nextPendingConnection();
while (sock_client)
{
connect(sock_client, SIGNAL(readyRead()),this, SLOT(new_data_recieved()));
connect(sock_client, SIGNAL(disconnected()),this,SLOT(client_closed()));
connect(sock_client, SIGNAL(error(QAbstractSocket::SocketError)),this, SLOT(displayError(QAbstractSocket::SocketError)));
connect(sock_client, SIGNAL(bytesWritten(qint64)), this, SLOT(some_data_sended(qint64)));
m_clientList[sock_client] = 0;
emit evt_NewClientConnected(sock_client);
sock_client = nextPendingConnection();
}
}
void QGHTcpServer::client_closed()
{
QTcpSocket * pSock = qobject_cast<QTcpSocket*>(sender());
if (pSock)
{
emit evt_ClientDisconnected(pSock);
m_buffer_sending.remove(pSock);
m_buffer_sending_offset.remove(pSock);
m_clientList.remove(pSock);
pSock->deleteLater();
}
}
void QGHTcpServer::new_data_recieved()
{
QTcpSocket * pSock = qobject_cast<QTcpSocket*>(sender());
if (pSock)
emit evt_Data_recieved(pSock,pSock->readAll());
}
void QGHTcpServer::some_data_sended(qint64 wsended)
{
QTcpSocket * pSock = qobject_cast<QTcpSocket*>(sender());
if (pSock)
{
emit evt_Data_transferred(pSock,wsended);
QList<QByteArray> & list_sock_data = m_buffer_sending[pSock];
QList<qint64> & list_offset = m_buffer_sending_offset[pSock];
while (list_sock_data.empty()==false)
{
QByteArray & arraySending = *list_sock_data.begin();
qint64 & currentOffset = *list_offset.begin();
qint64 nTotalBytes = arraySending.size();
assert(nTotalBytes>=currentOffset);
qint64 nBytesWritten = pSock->write(arraySending.constData()+currentOffset,qMin((int)(nTotalBytes-currentOffset),m_nPayLoad));
currentOffset += nBytesWritten;
if (currentOffset>=nTotalBytes)
{
list_offset.pop_front();
list_sock_data.pop_front();
}
else
break;
}
}
}
void QGHTcpServer::displayError(QAbstractSocket::SocketError socketError)
{
QTcpSocket * pSock = qobject_cast<QTcpSocket*>(sender());
if (pSock)
{
emit evt_SocketError(pSock,socketError);
pSock->disconnectFromHost();
}
}

void QGHTcpServer::SendDataToClient(QObject * objClient,const QByteArray & dtarray)
{
if (m_clientList.find(objClient)==m_clientList.end())
return;
QTcpSocket * pSock = qobject_cast<QTcpSocket*>(objClient);
if (pSock&&dtarray.size())
{
QList<QByteArray> & list_sock_data = m_buffer_sending[pSock];
QList<qint64> & list_offset = m_buffer_sending_offset[pSock];
if (list_sock_data.empty()==true)
{
qint64 bytesWritten = pSock->write(dtarray.constData(),qMin(dtarray.size(),m_nPayLoad));
if (bytesWritten < dtarray.size())
{
list_sock_data.push_back(dtarray);
list_offset.push_back(bytesWritten);
}
}
else
{
list_sock_data.push_back(dtarray);
list_offset.push_back(0);
}
}
}
void QGHTcpServer::BroadcastData(QObject * objClient,const QByteArray & dtarray)
{
for(QMap<QObject *,int>::iterator p = m_clientList.begin();p!=m_clientList.end();p++)
{
QTcpSocket * pSock = qobject_cast<QTcpSocket*>(p.key());
if (pSock&&dtarray.size()&&pSock!=objClient)
{
QList<QByteArray> & list_sock_data = m_buffer_sending[pSock];
QList<qint64> & list_offset = m_buffer_sending_offset[pSock];
if (list_sock_data.empty()==true)
{
qint64 bytesWritten = pSock->write(dtarray.constData(),qMin(dtarray.size(),m_nPayLoad));
if (bytesWritten < dtarray.size())
{
list_sock_data.push_back(dtarray);
list_offset.push_back(bytesWritten);
}
else
{
list_sock_data.push_back(dtarray);
list_offset.push_back(0);
}
}
}
}
}
void QGHTcpServer::KickAllClients()
{
QList<QObject *> clientList = m_clientList.keys();
foreach(QObject * obj,clientList)
{
QTcpSocket * pSock = qobject_cast<QTcpSocket*>(obj);
if (pSock)
{
pSock->disconnectFromHost();
}
}

}

下一次，我会介绍最后的实现功能。