? ?很多情形下，我们在应用程序的最外层都使用TCP作为可靠控制，下面，我就总结一下我在项目中使用QTcpServer与QTcpSocket的一些心得和体会。

? ? 服务端TCP程序可以利用QTcpServer，首先我们声名QTcpServer *对象（注意：QTcpServer占用的网络资源需要我们手动释放，任何我们程序可能异常退出或正常结束的地方QTcpServer *最后都要close())
? ? 注意我们的服务端要一直监听客户端
? tcpPort=8888;
? ? tcpServer=new QTcpServer();
? ? if(!tcpServer->listen(QHostAddress::Any,tcpPort))
? ? {
? ? ? ? tcpServer->close();
? ? ? ? emit MSG(QString("listen erro"));
? ? }
? ? connect(tcpServer,&QTcpServer::newConnection,this,&TcpServer::onNewConnection);
? ? 在新连接对应的槽里我们把
? QTcpSocket *newpeer=tcpServer->nextPendingConnection();
? 这个新连接的socket指针取下来，进行操作，当执行newpeer->write(QByterArray &MSG)即服务器向此peer发送数据；当执行QByterArray MSG=newpeer->write()即服务器读此peer的数据，所有信息的传递均是对QTcpSocket的操作,并要要对每一个socket的disconnected连接deleteLater槽防止内存泄漏。
? 说到此处，就牵涉到了QString 与QByterArray的转换，因为我们平时处理消息大多是对QSring进行处理：
? QString->QByterArray(只有英文(Latin)时)：
newpeer->write(QString("Server").toLatin1());
? QByterArray-> QString:
QTextCodec *tc= QTextCodec::codecForName("UTF-8");
QString str=tc->toUnicode((QByteArray)
rawreply)
下面的代码抽取自 我的服务端程序
#ifndef TCPSERVER_H
#define TCPSERVER_H

#include
#include
#include
class TcpServer : public QObject
{
? ? Q_OBJECT
public:
? ? explicit TcpServer(QObject *parent = 0);
? ? ~TcpServer();
private:
? ? int nb_peer;//总共的小伙伴数目，用于确定client->index的取值
? ? QTcpServer *tcpServer;
public slots:
? ? void ReadDataFromSocket();
? ? void onNewConnection();
? ? void onDisConnection();
? ? void processMSG(QString &MSG);
? // void processAddedClient(QTcpSocket *client);
};
#include "tcpserver.h"

TcpServer::TcpServer(QObject *parent) :
? ? QObject(parent),nb_peer(0)
{
? ? tcpPort=8888;
? ? tcpServer=new QTcpServer();
? ? if(!tcpServer->listen(QHostAddress::Any,tcpPort))
? ? {
? ? ? ? tcpServer->close();
? ? ? ? emit MSG(QString("listen erro"));
? ? }
? ? peerList = QList();
? ? connect(tcpServer,&QTcpServer::newConnection,this,&TcpServer::onNewConnection);
}
void TcpServer::onNewConnection()
{

? ? QTcpSocket *newpeer=tcpServer->nextPendingConnection();
? ? //写入验证

? ? connect(newpeer,SIGNAL(readyRead()),this,SLOT(ReadDataFromSocket()));
? ? connect(newpeer,SIGNAL(disconnected()),newpeer,SLOT(deleteLater()));
? ? connect(newpeer,SIGNAL(disconnected()),this,SLOT(onDisConnection()));
? ? newpeer->write(QString("Server").toLatin1());
? ? newpeer->flush();
}
#include
#include
void TcpServer::ReadDataFromSocket()
{
? ? QByteArray rawreply= static_cast(sender())->readAll();
? ? QTextCodec *tc= QTextCodec::codecForName("UTF-8");
? ? client beingCheckedClient;
? ? beingCheckedClient.index=nb_peer;
? ? beingCheckedClient.socket=static_cast(sender());
? ? if(tc->toUnicode(rawreply)!=QString("Client")&& !peerList.contains(beingCheckedClient
? ? ? ? ? ? ? ? ))
? ? {
? ? ? ? //写入信息
? ? ? ? //emit ChangeLabel(QString(rawreply));
? ? ? ? static_cast(sender())->write(
? ? ? ? ? ? ? ? ? ? QString("connect time out! disconnecting...").toLatin1());
? ? ? ? static_cast(sender())->flush();
? ? ? ? static_cast(sender())->disconnectFromHost();
? ? ? ? return ;
? ? }
}
TcpServer::~TcpServer()
{
? ? tcpServer->close();

}