5.关于QT中的网络编程，QTcpSocket，QUdpSocket



1
新建一个项目：TCPServer.pro

A 
修改TCPServer.pro,注意：如果是想使用网络库，需要加上network

SOURCES += \ TcpServer.cpp \ TcpClient.cpp HEADERS += \ TcpServer.h \ TcpClient.h QT += gui widgets network CONFIG += C++11

B
新建如下文件，因为要用到网络库，所以加上network

C
编写IP选择下拉选，头文件ChooseInterface.h

#ifndef CHOOSEINTERFACE_H #define CHOOSEINTERFACE_H #include <QDialog> #include <QComboBox> class ChooseInterface : public QDialog { Q_OBJECT public: explicit ChooseInterface(QWidget *parent ); QComboBox* _comboBox; QString _strSelect; signals: public slots: void slotComboBoxChange(QString); }; #endif // CHOOSEINTERFACE_H

编写ChooseInterface.cpp

#include "ChooseInterface.h" #include <QNetworkInterface> #include <QVBoxLayout> ChooseInterface::ChooseInterface(QWidget *parent) : QDialog(parent) { /* get all interface */ QList<QHostAddress> addrList = QNetworkInterface::allAddresses(); #if 0 QList<QNetworkInterface> infList = QNetworkInterface::allInterfaces(); QList<QNetworkAddressEntry> entryList = infList).addressEntries(); entryList).broadcast() #endif //编写一个下拉选 _comboBox = new QComboBox; QVBoxLayout* lay = new QVBoxLayout(this); lay->addWidget(_comboBox); foreach(QHostAddress addr, addrList) { //将地址都转换成为ipv4的地址 quint32 ipaddr = addr.toIPv4Address(); //的ip if(ipaddr == 0) continue; //在comboBox中添加下拉选 _comboBox->addItem(QHostAddress(ipaddr).toString()); } //当下拉选发生变化时的操作 connect(_comboBox, SIGNAL(currentIndexChanged(QString)), this, SLOT(slotComboBoxChange(QString))); } void ChooseInterface::slotComboBoxChange(QString str) { this->_strSelect = str; }

上面的运行结果是：

编写TcpServer.h

#ifndef TCPSERVER_H #define TCPSERVER_H #include <QWidget> #include <QTcpServer> #include <QTcpSocket> #include <QTextBrowser> class TcpServer:public QWidget { Q_OBJECT public: explicit TcpServer(QWidget *parent ); QTcpServer* _server; QTcpSocket* _socket; QTextBrowser* _show; signals: public slots: void slotNetConnection(); void slotReadyRead(); }; #endif // TCPSERVER_H

编写TcpServer.cpp

#include "TcpServer.h" #include <QHBoxLayout> #include <QNetworkInterface> #include <QMessageBox> #include "ChooseInterface.h" TcpServer::TcpServer(QWidget *parent) : QWidget(parent) { // 创建服务器并监听 _server = new QTcpServer; ChooseInterface dlg; dlg.exec(); //消息提示框 QMessageBox::information(NULL,"you select the ip:", dlg._strSelect); _server->listen(QHostAddress(dlg._strSelect), 9988); // 当有客户端来连接时，调用slotNetConnection方法 connect(_server, SIGNAL(newConnection()), this, SLOT(slotNetConnection())); _show = new QTextBrowser; QHBoxLayout* lay = new QHBoxLayout(this); lay->addWidget(_show); } void TcpServer::slotNetConnection() { // 判断是否有未处理的连接 while(_server->hasPendingConnections()) { // 调用nextPeddingConnection去获得连接的socket _socket = _server->nextPendingConnection(); _show->append("New connection ...."); // 为新的socket提供槽函数，来接收数据 connect(_socket, SIGNAL(readyRead()), this, SLOT(slotReadyRead())); } } void TcpServer::slotReadyRead() { // 接收数据，判断是否有数据，如果有，通过readAll函数获取所有数据 while(_socket->bytesAvailable() > 0) { _show->append("Data arrived ..... "); QByteArray buf = _socket->readAll(); _show->append(buf); } }

编写TcpClient.h

#ifndef TCPCLIENT_H #define TCPCLIENT_H #include <QWidget> #include <QTcpSocket> #include <QLineEdit> class TcpClient:public QWidget { Q_OBJECT public: explicit TcpClient(QWidget *parent ); QTcpSocket* _socket; QLineEdit* _lineEdit; signals: public slots: void slotButtonClick(); }; #endif // TCPCLIENT_H

编写TcpClient.cpp

#include "TcpClient.h" #include <QHBoxLayout> #include <QPushButton> TcpClient::TcpClient(QWidget *parent): QWidget(parent) { _socket = new QTcpSocket(this); _socket->connectToHost("127.0.0.1", 9988); _lineEdit = new QLineEdit; QHBoxLayout* lay = new QHBoxLayout(this); lay->addWidget(_lineEdit); QPushButton* button = new QPushButton("Send"); lay->addWidget(button); connect(button, SIGNAL(clicked()), this, SLOT(slotButtonClick())); connect(_lineEdit, SIGNAL(returnPressed()), this, SLOT(slotButtonClick())); } void TcpClient::slotButtonClick() { QString strText = _lineEdit->text(); if(strText.isEmpty()) return; _socket->write(strText.toUtf8()); _lineEdit->clear(); }

MyWidget.h

#ifndef MYWIDGET_H #define MYWIDGET_H #include <QWidget> class MyWidget : public QWidget { Q_OBJECT public: explicit MyWidget(QWidget *parent ); signals: public slots: }; #endif // MYWIDGET_H

MyWidget.cpp

#include "MyWidget.h" #include <QApplication> #include "TcpServer.h" #include "TcpClient.h" MyWidget::MyWidget(QWidget *parent) : QWidget(parent) { } int main(int argc,char** argv) { QApplication app(argc,argv); TcpServer s; s.show(); TcpClient c; c.show(); s.setWindowTitle("server"); c.setWindowTitle("client"); return app.exec(); }

运行结果：

2 
编写UDP程序

UDPServer.pro

QT += gui widgets network CONFIG += C++11 HEADERS += \ Udp1.h \ Udp2.h \ MyWidget.h SOURCES += \ Udp1.cpp \ Udp2.cpp \ MyWidget.cpp

Udp1.h

#ifndef UDP1_H #define UDP1_H #include <QWidget> #include <QUdpSocket> class Udp1 : public QWidget { Q_OBJECT public: explicit Udp1(QWidget *parent ); QUdpSocket* _udp; signals: public slots: void slotReadyRead(); }; #endif // UDP1_H

Udp1.cpp

#include "udp1.h" #include <QTimer> #include <QDateTime> Udp1::Udp1(QWidget *parent) : QWidget(parent) { // 创建udpsocket，并连接槽函数，用来接收数据 _udp = new QUdpSocket; _udp->bind(10001); connect(_udp, SIGNAL(readyRead()), this, SLOT(slotReadyRead())); // 使用定时器来定时发送时间戳 QTimer* timer = new QTimer; timer->setInterval(1000); timer->start(); connect(timer, &QTimer::timeout, [&](){ quint64 timestamp = QDateTime::currentMSecsSinceEpoch(); QString str = QString::number(timestamp); #if 0 // 普通UDPsocket发送 _udp->writeDatagram(str.toUtf8(), QHostAddress("127.0.0.1"), ); #else // 广播发送，注意：QHostAddress::Broadcast是255.255.255.255, 192.168.6.255 //   _udp->writeDatagram(str.toUtf8(), QHostAddress::Broadcast, 10002); // multicast, 224.0.0.1~224.0.0.255 is multicast address of LAN _udp->writeDatagram(str.toUtf8(), QHostAddress("224.0.0.131"), 10002); #endif }); } void Udp1::slotReadyRead() { while(_udp->hasPendingDatagrams()) { quint32 datagramSize = _udp->pendingDatagramSize(); QByteArray buf(datagramSize, 0); _udp->readDatagram(buf.data(), buf.size()); qDebug() <<"Udp1"<< buf; } }

Udp2.h

#ifndef UDP2_H #define UDP2_H #include <QWidget> #include <QUdpSocket> class Udp2 : public QWidget { Q_OBJECT public: explicit Udp2(QWidget *parent ); QUdpSocket* _udp; signals: public slots: void slotReadyRead(); }; #endif // UDP2_H

Udp2.cpp

#include "udp2.h" #include <QTimer> #include <QDateTime> #include <QLineEdit> Udp2::Udp2(QWidget *parent) : QWidget(parent) { _udp = new QUdpSocket; // the address of bind and multicast must be same tpye(IPV4 or IPV6) _udp->bind(QHostAddress::AnyIPv4, 10002); // join the multicast address (224.0.0.131) for recv mulicast package _udp->joinMulticastGroup(QHostAddress("224.0.0.131")); connect(_udp, SIGNAL(readyRead()), this, SLOT(slotReadyRead())); QTimer* timer = new QTimer(this); timer->setInterval(1000); timer->start(); connect(timer, &QTimer::timeout, [&](){ quint64 timestamp = QDateTime::currentMSecsSinceEpoch(); QString str = QString::number(timestamp); _udp->writeDatagram(str.toUtf8(), QHostAddress("127.0.0.1"), 10001); }); } void Udp2::slotReadyRead() { while(_udp->hasPendingDatagrams()) { quint32 datagramSize = _udp->pendingDatagramSize(); QByteArray buf(datagramSize, 0); _udp->readDatagram(buf.data(), buf.size()); qDebug() << "Udp2" <<buf; } }

运行结果： 控制台输出结果如下：