复习的心态过一遍之前基础的一些东西，Qt封装了QTcpServer和QTcpSocket两个类，其中QTcpServer继承自QObject，通过listen()函数监听传入的客户端连接，当Client连接上时，QTcpServer会发出newConnection的信号，在对应的槽函数中使用nextPendingConnection()拿到连接的客户端的句柄和信息。
而QTcpSocket则是读写数据的时候使用，过程很简单。
服务器流程：listen->newConnection->nextPendingConnection->readAll/write
客户端流程：connectToHost->waitForConnected->write/readAll
需要注意的是在使用网络相关的类前，需要在pro文件加上QT += network
通信时：
客户端掉线时：
QTcpServer服务器代码（包含.h和.cpp）:
.h
#ifndef WIDGET_H
#define WIDGET_H
#include <QWidget>
#include <QTcpServer>
#include <QTcpSocket>
QT_BEGIN_NAMESPACE
namespace Ui { class Widget; }
QT_END_NAMESPACE
class Widget : public QWidget
{
Q_OBJECT
public:
Widget(QWidget *parent = nullptr);
~Widget();
protected slots:
void onSendBtnClicked();
void onNewClientConnected();
void onRecvData();
void onClientDisconnected();
private:
void Init();
private:
Ui::Widget *ui;
private:
QTcpServer *_tcpServer;
QTcpSocket *_tcpSocket;
};
#endif // WIDGET_H.cpp
#include "widget.h"
#include "ui_widget.h"
#include <QHostAddress>
#include <QDebug>
#define MyTcpPort 8886
Widget::Widget(QWidget *parent)
: QWidget(parent)
, ui(new Ui::Widget)
,_tcpServer(nullptr)
,_tcpSocket(nullptr)
{
ui->setupUi(this);
connect(this->ui->btn_send,&QPushButton::clicked,this,&Widget::onSendBtnClicked);
Init();
setWindowTitle("服务端");
}
Widget::~Widget()
{
delete ui;
if(_tcpSocket)
{
_tcpSocket->disconnect();
_tcpSocket->abort();
_tcpSocket->close();
_tcpSocket->deleteLater();
}
if(_tcpServer)
{
_tcpServer->close();
delete _tcpServer;
}
}
void Widget::Init()
{
_tcpSocket = new QTcpSocket;
_tcpServer = new QTcpServer;
int ret = _tcpServer->listen(QHostAddress::AnyIPv4,MyTcpPort);
if(ret==0)
{
qDebug()<<"_tcpServer->listen is failied";
return;
}
connect(_tcpServer,&QTcpServer::newConnection,this,&Widget::onNewClientConnected);
}
void Widget::onSendBtnClicked()
{
if(!_tcpSocket) return;
QString inputText = ui->inputEdit->text();
if(inputText.isEmpty())
return;
//发送数据
int ret = _tcpSocket->write(inputText.toStdString().c_str());
if(ret<0)
{
qDebug()<<"write to client is failed!";
}
}
void Widget::onNewClientConnected()
{
if(_tcpServer->hasPendingConnections())
{
_tcpSocket = _tcpServer->nextPendingConnection();
if(!_tcpSocket->isValid()) return;
connect(_tcpSocket,&QTcpSocket::readyRead,this,
&Widget::onRecvData);
connect(_tcpSocket,&QTcpSocket::disconnected,this,
&Widget::onClientDisconnected);
}
}
void Widget::onRecvData()
{
if(!_tcpSocket) return;
QString recvData=_tcpSocket->readAll();
qDebug()<<"recvData:"<<recvData;
this->ui->recvEdit->append(recvData);
}
void Widget::onClientDisconnected()
{
QString clientIp = _tcpSocket->peerAddress().toString();
this->ui->recvEdit->append(clientIp+" is Drop line!");
}QTcpClient客户端代码（包含.h和.cpp）:
/.h
#ifndef WIDGET_H
#define WIDGET_H
#include <QWidget>
#include <QTcpSocket>
QT_BEGIN_NAMESPACE
namespace Ui { class Widget; }
QT_END_NAMESPACE
class Widget : public QWidget
{
Q_OBJECT
public:
Widget(QWidget *parent = nullptr);
~Widget();
private:
void Init();
protected slots:
void onSendBtnClicked();
void onRecvData();
private:
Ui::Widget *ui;
private:
QTcpSocket *_tcpClient;
};
#endif // WIDGET_H
/.cpp
#include "widget.h"
#include "ui_widget.h"
#define MyTcpPort 8886
Widget::Widget(QWidget *parent)
: QWidget(parent)
, ui(new Ui::Widget),_tcpClient(nullptr)
{
ui->setupUi(this);
connect(this->ui->btn_send,&QPushButton::clicked,this,&Widget::onSendBtnClicked);
Init();
setWindowTitle("客户端");
}
Widget::~Widget()
{
delete ui;
if(_tcpClient)
{
_tcpClient->close();
_tcpClient->deleteLater();
}
}
void Widget::Init()
{
_tcpClient=new QTcpSocket;
_tcpClient->abort();
_tcpClient->connectToHost("127.0.0.1",MyTcpPort);
if(!_tcpClient->waitForConnected(2000))
{
qDebug()<<"connect is failed!";
return;
}
qDebug()<<"connect is successful";
connect(_tcpClient,&QTcpSocket::readyRead,this,&Widget::onRecvData);
}
void Widget::onSendBtnClicked()
{
if(!_tcpClient) return;
QString wStr=ui->inputEdit->text();
int ret = _tcpClient->write(wStr.toStdString().c_str());
if(ret<0)
{
qDebug()<<"send data is failed";
}
qDebug()<<"send data is successful!";
}
void Widget::onRecvData()
{
if(!_tcpClient) return;
QString recvData= _tcpClient->readAll();
ui->recvEdit->append(recvData);
qDebug()<<"recvData:"<<recvData;
}
