一.QT5.12实现TCP客户端和服务端功能
1.QT中实现TCP通信主要用到了以下类:QTcpServer、QTcpSocket、QHostAddress
2.基本流程:
使用QTcpServer来创建一个TCP服务器,在新的连接建立时,将新建立连接的socket添加到列表中,以便发送数据,同时监听在指定的IP地址和端口上,并在有新的客户端连接上来时进行处理;
使用QTcpSocket来创建一个TCP客户端,连接到服务器并发送数据;
二.代码示例
1.mainwindow.h
#ifndef MAINWINDOW_H
#define MAINWINDOW_H
#include <QMainWindow>
#include <QTcpServer>
#include <QLabel>
namespace Ui {
class MainWindow;
}
class MainWindow : public QMainWindow
{
Q_OBJECT
private:
QLabel *LabListen;//状态栏标签
QLabel *LabSocketState;//状态栏标签
QTcpServer *tcpServer; //TCP服务器
QTcpSocket *tcpSocket;//TCP通讯的Socket
QString getLocalIP();//获取本机IP地址
protected:
void closeEvent(QCloseEvent *event);
public:
explicit MainWindow(QWidget *parent = 0);
~MainWindow();
private slots:
//自定义槽函数
void onNewConnection();//QTcpServer的newConnection()信号
void onSocketStateChange(QAbstractSocket::SocketState socketState);
void onClientConnected(); //Client Socket connected
void onClientDisconnected();//Client Socket disconnected
void onSocketReadyRead();//读取socket传入的数据
//UI生成的
void on_actStart_triggered();
void on_actStop_triggered();
void on_actClear_triggered();
void on_btnSend_clicked();
void on_actHostInfo_triggered();
private:
Ui::MainWindow *ui;
};
#endif // MAINWINDOW_H
2.mainwindow.cpp
#include "mainwindow.h"
#include "ui_mainwindow.h"
#include <QtNetwork>
QString MainWindow::getLocalIP()
{//获取本机IPv4地址
QString hostName=QHostInfo::localHostName();//本地主机名
QHostInfo hostInfo=QHostInfo::fromName(hostName);
QString localIP="";
QList<QHostAddress> addList=hostInfo.addresses();//
if (!addList.isEmpty())
for (int i=0;i<addList.count();i++)
{
QHostAddress aHost=addList.at(i);
if (QAbstractSocket::IPv4Protocol==aHost.protocol())
{
localIP=aHost.toString();
break;
}
}
return localIP;
}
void MainWindow::closeEvent(QCloseEvent *event)
{//关闭窗口时停止监听
if (tcpServer->isListening())
tcpServer->close();;//停止网络监听
event->accept();
}
MainWindow::MainWindow(QWidget *parent) :
QMainWindow(parent),
ui(new Ui::MainWindow)
{
ui->setupUi(this);
LabListen=new QLabel("监听状态:");
LabListen->setMinimumWidth(150);
ui->statusBar->addWidget(LabListen);
LabSocketState=new QLabel("Socket状态:");//
LabSocketState->setMinimumWidth(200);
ui->statusBar->addWidget(LabSocketState);
QString localIP=getLocalIP();//本机IP
this->setWindowTitle(this->windowTitle()+"----本机IP:"+localIP);
ui->comboIP->addItem(localIP);
tcpServer=new QTcpServer(this);
connect(tcpServer,SIGNAL(newConnection()),this,SLOT(onNewConnection()));
}
MainWindow::~MainWindow()
{
delete ui;
}
void MainWindow::onNewConnection()
{
// ui->plainTextEdit->appendPlainText("有新连接");
tcpSocket = tcpServer->nextPendingConnection(); //创建socket
connect(tcpSocket, SIGNAL(connected()),
this, SLOT(onClientConnected()));
onClientConnected();//
connect(tcpSocket, SIGNAL(disconnected()),
this, SLOT(onClientDisconnected()));
connect(tcpSocket,SIGNAL(stateChanged(QAbstractSocket::SocketState)),
this,SLOT(onSocketStateChange(QAbstractSocket::SocketState)));
onSocketStateChange(tcpSocket->state());
connect(tcpSocket,SIGNAL(readyRead()),
this,SLOT(onSocketReadyRead()));
}
void MainWindow::onSocketStateChange(QAbstractSocket::SocketState socketState)
{//socket状态变化时
switch(socketState)
{
case QAbstractSocket::UnconnectedState:
LabSocketState->setText("scoket状态:UnconnectedState");
break;
case QAbstractSocket::HostLookupState:
LabSocketState->setText("scoket状态:HostLookupState");
break;
case QAbstractSocket::ConnectingState:
LabSocketState->setText("scoket状态:ConnectingState");
break;
case QAbstractSocket::ConnectedState:
LabSocketState->setText("scoket状态:ConnectedState");
break;
case QAbstractSocket::BoundState:
LabSocketState->setText("scoket状态:BoundState");
break;
case QAbstractSocket::ClosingState:
LabSocketState->setText("scoket状态:ClosingState");
break;
case QAbstractSocket::ListeningState:
LabSocketState->setText("scoket状态:ListeningState");
}
}
void MainWindow::onClientConnected()
{//客户端接入时
ui->plainTextEdit->appendPlainText("**client socket connected");
ui->plainTextEdit->appendPlainText("**peer address:"+
tcpSocket->peerAddress().toString());
ui->plainTextEdit->appendPlainText("**peer port:"+
QString::number(tcpSocket->peerPort()));
}
void MainWindow::onClientDisconnected()
{//客户端断开连接时
ui->plainTextEdit->appendPlainText("**client socket disconnected");
tcpSocket->deleteLater();
// deleteLater();//QObject::deleteLater();
}
void MainWindow::onSocketReadyRead()
{//读取缓冲区行文本
// QStringList lines;
while(tcpSocket->canReadLine())
ui->plainTextEdit->appendPlainText("[in] "+tcpSocket->readLine());
// lines.append(clientConnection->readLine());
}
void MainWindow::on_actStart_triggered()
{//开始监听
QString IP=ui->comboIP->currentText();//IP地址
quint16 port=ui->spinPort->value();//端口
QHostAddress addr(IP);
tcpServer->listen(addr,port);//
ui->plainTextEdit->appendPlainText("**开始监听...");
ui->plainTextEdit->appendPlainText("**服务器地址:"
+tcpServer->serverAddress().toString());
ui->plainTextEdit->appendPlainText("**服务器端口:"
+QString::number(tcpServer->serverPort()));
ui->actStart->setEnabled(false);
ui->actStop->setEnabled(true);
LabListen->setText("监听状态:正在监听");
}
void MainWindow::on_actStop_triggered()
{//停止监听
if (tcpServer->isListening()) //tcpServer正在监听
{
tcpServer->close();//停止监听
ui->actStart->setEnabled(true);
ui->actStop->setEnabled(false);
LabListen->setText("监听状态:已停止监听");
}
}
void MainWindow::on_actClear_triggered()
{
ui->plainTextEdit->clear();
}
void MainWindow::on_btnSend_clicked()
{//发送一行字符串,以换行符结束
QString msg=ui->editMsg->text();
ui->plainTextEdit->appendPlainText("[out] "+msg);
ui->editMsg->clear();
ui->editMsg->setFocus();
QByteArray str=msg.toUtf8();
str.append('\n');//添加一个换行符
tcpSocket->write(str);
}
void MainWindow::on_actHostInfo_triggered()
{//获取本机地址
QString hostName=QHostInfo::localHostName();//本地主机名
ui->plainTextEdit->appendPlainText("本机主机名:"+hostName+"\n");
QHostInfo hostInfo=QHostInfo::fromName(hostName);
QList<QHostAddress> addList=hostInfo.addresses();//
if (!addList.isEmpty())
for (int i=0;i<addList.count();i++)
{
QHostAddress aHost=addList.at(i);
if (QAbstractSocket::IPv4Protocol==aHost.protocol())
{
QString IP=aHost.toString();
ui->plainTextEdit->appendPlainText("本机IP地址:"+aHost.toString());
if (ui->comboIP->findText(IP)<0)
ui->comboIP->addItem(IP);
}
}
}
三.测试结果