TCP
        TCP是一个基于流的协议。对于应用程序，数据表现为一个长长的流，而不是一个大大的平面文件。基于TCP的高层协议通常是基于行的或者基于块的。
          ●、基于行的协议把数据作为一行文本进行传输，每行都以一个换行符结尾。
          ●、基于块的协议把数据作为二进制块进行传输，每块是由一个size大小字段和紧跟它的一个size字节的数据组成。
        QTcpSocket通过器父类QAbstractSocket继承了QIODevice，因此他可以通过使用QTextStream和QDataStream来进行读取和写入。
        QTcpServer类在服务器端处理来自TCP客户端连接数据，需要注意的是，该类直接继承于QObject基类，而不是QAbstractSocket抽象套接字类。

 

一 QTcpServer

#ifndef VXMAINWINDOW_H
#define VXMAINWINDOW_H

#include <QWidget>
#include <QtNetwork/QTcpServer>
#include <QtNetwork/QTcpSocket>

class QPushButton;
class QTextEdit;

class CVxMainWindow : public QWidget
{
 Q_OBJECT

public:
 CVxMainWindow(QWidget *parent = NULL);
 ~CVxMainWindow();
protected:
 void resizeEvent(QResizeEvent *);
private slots:
 void Btn_ListenClickedSlot();
 void Btn_StopListenClickedSlot();
 void newConnectionSlot();
 void dataReceived();
private:
 QTcpServer *m_pServer;
 QTcpSocket *m_pSocket;

 QPushButton *m_pBtn_Listen;
 QPushButton *m_pBtn_StopListen;
 QTextEdit   *m_pEdt_Info;
};

#endif // VXMAINWINDOW_H

 

#include "VxMainWindow.h"

#include <QtGui/QtGui>

CVxMainWindow::CVxMainWindow(QWidget *parent)
 : QWidget(parent)
{
 m_pBtn_Listen     = new QPushButton(QObject::tr("开始监听"), this);
 m_pBtn_StopListen = new QPushButton(QObject::tr("停止监听"), this);
 m_pEdt_Info = new QTextEdit(this);
 m_pServer = new QTcpServer(this);
 
 connect(m_pBtn_Listen,     SIGNAL(clicked()), this, SLOT(Btn_ListenClickedSlot()));
 connect(m_pBtn_StopListen, SIGNAL(clicked()), this, SLOT(Btn_StopListenClickedSlot()));
 connect(m_pServer, SIGNAL(newConnection()), this, SLOT(newConnectionSlot()));
}

CVxMainWindow::~CVxMainWindow()
{

}

void CVxMainWindow::resizeEvent(QResizeEvent *)
{
 m_pBtn_Listen->setGeometry(10, 5, 80, 20);
 m_pBtn_StopListen->setGeometry(100, 5, 80, 20);
 m_pEdt_Info->setGeometry(0, 30, width(), height() - 30);
}

void CVxMainWindow::Btn_ListenClickedSlot()
{
 if (!m_pServer->isListening())
 {
  if (m_pServer->listen(QHostAddress::Any, 8080)) 
  {
   m_pEdt_Info->append(QObject::tr("打开监听端口成功！"));
  }
  else
  {
   m_pEdt_Info->append(QObject::tr("打开监听端口失败！"));
  }
 }
 else
 {
  m_pEdt_Info->append(QObject::tr("正在监听中...！"));
 }
}

void CVxMainWindow::Btn_StopListenClickedSlot()
{
 if (m_pServer->isListening())
 {
  m_pServer->close();
  m_pEdt_Info->append(QObject::tr("停止监听！"));
 }
}

void CVxMainWindow::newConnectionSlot()
{
 m_pEdt_Info->append(QObject::tr("有新客户端连接到服务器"));
 m_pSocket = m_pServer->nextPendingConnection();
 connect(m_pSocket, SIGNAL(disconnected()), m_pSocket, SLOT(deleteLater()));
 connect(m_pSocket, SIGNAL(readyRead()),this, SLOT(dataReceived()));

 int length = 0;
 QString vMsgStr = QObject::tr("Welcome");
 if((length=m_pSocket->write(vMsgStr.toLatin1(),vMsgStr.length()))!=vMsgStr.length())
 {

 }
}

void CVxMainWindow::dataReceived()
{
 while(m_pSocket->bytesAvailable())
 {       
  QByteArray vTemp;
  vTemp = m_pSocket->readLine();  

  QString vTempStr(vTemp);
  m_pEdt_Info->append(vTempStr);

  int length = 0;
  QString vMsgStr = QObject::tr("回复：") + vTempStr;
  if((length=m_pSocket->write(vMsgStr.toLatin1(),vMsgStr.length()))!=vMsgStr.length())
  {

  }
 }
}

 

二 QTcpSocket

 

 

#ifndef VXMAINWINDOW_H
#define VXMAINWINDOW_H

#include <QWidget>
#include <QtNetwork/QTcpSocket>
#include <QtNetwork/QHostAddress>

class QPushButton;
class QTextEdit;
class QLineEdit;

class CVxMainWindow : public QWidget
{
 Q_OBJECT

public:
 CVxMainWindow(QWidget *parent = NULL);
 ~CVxMainWindow();
protected:
 void resizeEvent(QResizeEvent *);
private slots:
 void Btn_ConnectClickedSlot();
 void Btn_DisConnectClickedSlot();
 void Btn_SendClickedSlot();
 void connectedSlot();
 void disconnectedSlot();
 void dataReceived();
 void displayError(QAbstractSocket::SocketError);
private:
 QTcpSocket *m_pSocket;
 QHostAddress m_HostAddress;

 QPushButton *m_pBtn_Connect;
 QPushButton *m_pBtn_DisConnect;
 QTextEdit   *m_pEdt_Info;
 QLineEdit   *m_pEdt_Send;
 QPushButton *m_pBtn_Send;
};

#endif // VXMAINWINDOW_H

 

#include "VxMainWindow.h"

#include <QtGui/QtGui>

CVxMainWindow::CVxMainWindow(QWidget *parent)
 : QWidget(parent)
{
 m_pBtn_Connect    = new QPushButton(QObject::tr("连接服务器"), this);
 m_pBtn_DisConnect = new QPushButton(QObject::tr("断开连接"), this);
 m_pEdt_Send       = new QLineEdit(this);
 m_pBtn_Send       = new QPushButton(QObject::tr("发送"), this);
 m_pEdt_Info = new QTextEdit(this);
 m_pSocket = new QTcpSocket(this);

 connect(m_pBtn_Connect,    SIGNAL(clicked()), this, SLOT(Btn_ConnectClickedSlot()));
 connect(m_pBtn_DisConnect, SIGNAL(clicked()), this, SLOT(Btn_DisConnectClickedSlot()));
 connect(m_pBtn_Send,       SIGNAL(clicked()), this, SLOT(Btn_SendClickedSlot()));
 connect(m_pSocket, SIGNAL(connected()), this, SLOT(connectedSlot()));
 connect(m_pSocket, SIGNAL(disconnected()), this, SLOT(disconnectedSlot()));
 connect(m_pSocket, SIGNAL(readyRead()),this, SLOT(dataReceived()));
 connect(m_pSocket, SIGNAL(error(QAbstractSocket::SocketError)), this, SLOT(displayError(QAbstractSocket::SocketError)));
}

CVxMainWindow::~CVxMainWindow()
{

}

void CVxMainWindow::resizeEvent(QResizeEvent *)
{
 m_pBtn_Connect->setGeometry(10, 5, 80, 20);
 m_pBtn_DisConnect->setGeometry(100, 5, 80, 20);
 m_pEdt_Send->setGeometry(10, 30, 150, 20);
 m_pBtn_Send->setGeometry(170, 30, 80, 20);
 m_pEdt_Info->setGeometry(0, 60, width(), height() - 60);
}

void CVxMainWindow::Btn_ConnectClickedSlot()
{
 m_HostAddress.setAddress(QObject::tr("127.0.0.1"));
 m_pSocket->connectToHost(m_HostAddress, 8080);
}

void CVxMainWindow::Btn_DisConnectClickedSlot()
{
 m_pSocket->disconnectFromHost();
}

void CVxMainWindow::Btn_SendClickedSlot()
{
 int length = 0;
 QString vMsgStr = m_pEdt_Send->text();
 if((length = m_pSocket->write(vMsgStr.toLatin1(),vMsgStr.length())) != vMsgStr.length())
 {
  m_pEdt_Info->append(QObject::tr("发送信息失败：") + vMsgStr);
 }
}

void CVxMainWindow::connectedSlot()
{
 m_pEdt_Info->append(QObject::tr("成功连接到服务器！"));
}

void CVxMainWindow::disconnectedSlot()
{
 m_pEdt_Info->append(QObject::tr("断开与服务器的连接！"));
}

void CVxMainWindow::dataReceived()
{
 while(m_pSocket->bytesAvailable())
 {       
  QString vTemp;
  vTemp = m_pSocket->readLine();          
  m_pEdt_Info->append(vTemp);
 }
}

void CVxMainWindow::displayError(QAbstractSocket::SocketError)
{

}

 

void XXX()
{
 // 用于暂存我们要发送的数据
 QByteArray block; 
 // 使用数据流写入数据
 QDataStream out(&block,QIODevice::WriteOnly);
 // 设置数据流的版本，客户端和服务器端使用的版本要相同
 out.setVersion(QDataStream::Qt_4_7);
 out<<(quint16) 0;

 out<<QObject::tr("您好啊!");
 out.device()->seek(0);
 out<<(quint16)(block.size() - sizeof(quint16));
 m_pSocket->write(block);
}

void CVxMainWindow::dataReceived()
{
 QString vTempStr;  
 quint16 blockSize = 0;

 QDataStream in(m_pSocket);
 // 设置数据流版本，这里要和服务器端相同
 in.setVersion(QDataStream::Qt_4_7);
 // 如果是刚开始接收数据
 if(blockSize == 0) 
 {
  //判断接收的数据是否有两字节，也就是文件的大小信息
  //如果有则保存到blockSize变量中，没有则返回，继续接收数据
  if(m_pSocket->bytesAvailable() < (int)sizeof(quint16)) return;
  in >> blockSize;
 }
 // 如果没有得到全部的数据，则返回，继续接收数据
 if(m_pSocket->bytesAvailable() < blockSize) return;
 in >> vTempStr;
 m_pEdt_Info->append(vTempStr);
}