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QT/C++——网络编程

一、基础知识复习

这部分内容前面讲的比较详细，现在就是简单复习一下。

两台主机之间通信要经过封包他有一堆包头

TCP、UDP都是基于套接字，C写我感觉已经挺简单了，老师说C++更简单，我们往下学学看。

二、UDP

网络编程这块要在工程文件中加上network

服务器是被动套接字，客户端是主动套接字

客户端：

  1. #ifndef WIDGET_H
  2. #define WIDGET_H
  4. #include <QWidget>
  5. #include <QTextEdit>
  6. #include <QLineEdit>
  7. #include <QPushButton>
  8. #include <QUdpSocket>
  9. #include <QHostAddress>
  11. class Widget : public QWidget
  12. {
  13.     Q_OBJECT
  14. public slots:
  15.     void senddata()
  16.     {
  17.         udpsock->writeDatagram(le->text().toStdString().c_str(), QHostAddress("192.168.3.27"), 8888);
  18.     }
  20.     void recvdata()
  21.     {
  22.         QByteArray datagram;
  23.         datagram.resize(udpsock->pendingDatagramSize());
  24.         QHostAddress sender;
  25.         quint16 senderPort;
  27.         udpsock->readDatagram(datagram.data(), datagram.size(),
  28.                                           &sender, &senderPort);
  29.         te->append(datagram);
  30.     }
  31. public:
  32.     Widget(QWidget *parent = 0);
  33.     ~Widget();
  34. private:
  35.     QTextEdit *te;
  36.     QLineEdit *le;
  37.     QPushButton *pb;
  39.     QUdpSocket *udpsock;
  40. };
  42. #endif // WIDGET_H
  1. #include "widget.h"
  2. #include <QVBoxLayout>
  4. Widget::Widget(QWidget *parent)
  5.     : QWidget(parent)
  6. {
  7.     te = new QTextEdit;
  8.     le = new QLineEdit;
  9.     pb = new QPushButton("send");
  10.     QVBoxLayout *vbox = new QVBoxLayout;
  11.     vbox->addWidget(te);
  12.     vbox->addWidget(le);
  13.     vbox->addWidget(pb);
  14.     setLayout(vbox);
  16.     udpsock = new QUdpSocket;
  18.     connect(pb, SIGNAL(clicked(bool)), this, SLOT(senddata()));
  19.     connect(udpsock, SIGNAL(readyRead()), this, SLOT(recvdata()));
  20. }
  22. Widget::~Widget()
  23. {
  25. }

服务器：

  1. #ifndef UDPSERVER_H
  2. #define UDPSERVER_H
  4. #include <QObject>
  5. #include <QUdpSocket>
  6. #include <QDebug>
  8. class udpServer : public QObject
  9. {
  10.     Q_OBJECT
  11. public:
  12.     explicit udpServer(QObject *parent = 0);
  13.     void init()
  14.     {
  15.         udpSocket = new QUdpSocket(this);
  16.         udpSocket->bind(QHostAddress::AnyIPv4, 8888);
  18.         connect(udpSocket, SIGNAL(readyRead()),
  19.                       this, SLOT(readPendingDatagrams()));
  20.         qDebug()<<"init....";
  21.     }
  22. signals:
  24. public slots:
  25.     void readPendingDatagrams()
  26.     {
  27.         while (udpSocket->hasPendingDatagrams()) {
  28.                   QByteArray datagram;
  29.                   datagram.resize(udpSocket->pendingDatagramSize());
  30.                   QHostAddress sender;
  31.                   quint16 senderPort;
  33.                   udpSocket->readDatagram(datagram.data(), datagram.size(),
  34.                                           &sender, &senderPort);
  36.                   //processTheDatagram(datagram);
  37.                   qDebug()<<"recv: "<<datagram;
  39.                   udpSocket->writeDatagram(datagram.data(), datagram.size(),
  40.                                            sender, senderPort);
  41.               }
  42.     }
  44. private:
  45.     QUdpSocket *udpSocket;
  46. };
  48. #endif // UDPSERVER_H

两个程序的工程文件中一定要加入network

三、TCP

服务器：

  1. #ifndef TCPSERVER_H
  2. #define TCPSERVER_H
  4. #include <QObject>
  5. #include <QTcpServer>
  6. #include <QTcpSocket>
  7. #include <QDebug>
  9. class tcpServer : public QObject
  10. {
  11.     Q_OBJECT
  12. public:
  13.     explicit tcpServer(QObject *parent = 0);
  15. signals:
  17. public slots:
  18.     void newconnected()
  19.     {
  20.         qDebug()<<"connected";
  21.         clientsock = ser->nextPendingConnection();
  23.         connect(clientsock, SIGNAL(readyRead()), this, SLOT(readdata()));
  24.     }
  26.     void readdata()
  27.     {
  28.         QByteArray buf =  clientsock->readAll();
  29.         qDebug()<<"recv: "<<buf;
  30.         clientsock->write(buf);
  31.     }
  33. private:
  34.     QTcpServer *ser;
  35.     QTcpSocket *clientsock;
  37. };
  39. #endif // TCPSERVER_H
  1. #include "tcpserver.h"
  2. #include <QHostAddress>
  4. tcpServer::tcpServer(QObject *parent) : QObject(parent)
  5. {
  6.     ser = new QTcpServer;
  7.     ser->listen(QHostAddress::AnyIPv4, 8888);
  8.     connect(ser, SIGNAL(newConnection()), this, SLOT(newconnected()));
  10.     ser->waitForNewConnection();
  11. }

客户端：

  1. #ifndef WIDGET_H
  2. #define WIDGET_H
  4. #include <QWidget>
  5. #include <QTextEdit>
  6. #include <QLineEdit>
  7. #include <QPushButton>
  8. #include <QTcpSocket>
  10. class Widget : public QWidget
  11. {
  12.     Q_OBJECT
  13. public slots:
  14.     void senddata()
  15.     {
  16.         tcpsocket->write(le->text().toStdString().c_str());
  17.     }
  19.     void recvdata()
  20.     {
  21.         QByteArray buf = tcpsocket->readAll();
  22.         te->append(buf);
  23.     }
  24. public:
  25.     Widget(QWidget *parent = 0);
  26.     ~Widget();
  27. private:
  28.     QTextEdit *te;
  29.     QLineEdit *le;
  30.     QPushButton *pb;
  32.     QTcpSocket *tcpsocket;
  33. };
  35. #endif // WIDGET_H
  1. #include "widget.h"
  2. #include <QVBoxLayout>
  3. #include <QHostAddress>
  5. Widget::Widget(QWidget *parent)
  6.     : QWidget(parent)
  7. {
  8.     te = new QTextEdit;
  9.     le = new QLineEdit;
  10.     pb = new QPushButton("send");
  12.     QVBoxLayout *vbox = new QVBoxLayout;
  13.     vbox->addWidget(te);
  14.     vbox->addWidget(le);
  15.     vbox->addWidget(pb);
  16.     setLayout(vbox);
  18.     tcpsocket = new QTcpSocket;
  19.     //connect to server
  20.     tcpsocket->connectToHost(QHostAddress("192.168.3.27"), 8888);
  22.     connect(pb, SIGNAL(clicked(bool)), this, SLOT(senddata()));
  23.     connect(tcpsocket, SIGNAL(readyRead()), this, SLOT(recvdata()));
  24. }
  26. Widget::~Widget()
  27. {
  29. }

四、小项目

实现一个类似于监控的东西

就是把传输内容换成了照片

客户端：

  1. #ifndef WIDGET_H
  2. #define WIDGET_H
  4. #include <QWidget>
  5. #include <QLabel>
  6. #include <QLineEdit>
  7. #include <QTcpSocket>
  8. #include <QPushButton>
  9. #include <QHostAddress>
  10. #include <QDebug>
  11. #include <QPixmap>
  13. class Widget : public QWidget
  14. {
  15.     Q_OBJECT
  17. public:
  18.     Widget(QWidget *parent = 0);
  19.     ~Widget();
  21. public slots:
  22.     void startv()
  23.     {
  24.         readsize = true;
  26.         sockv = new QTcpSocket(this);
  27.         connect(sockv, SIGNAL(readyRead()), this, SLOT(recv_show()));
  28.         sockv->connectToHost(QHostAddress(leip->text()), atoi(leport->text().toStdString().c_str()));
  29.         btstart->setText("STOP");
  30.         leip->setDisabled(true);
  31.         leport->setDisabled(true);
  33.         disconnect(btstart, SIGNAL(clicked()), this, SLOT(startv()));
  34.         connect(btstart, SIGNAL(clicked()), this, SLOT(stop()));
  35.     }
  37.     void stop()
  38.     {
  39.         sockv->close();
  40.         sockv->deleteLater();
  42.         disconnect(btstart, SIGNAL(clicked()), this, SLOT(stop()));
  43.         connect(btstart, SIGNAL(clicked()), this, SLOT(startv()));
  45.         leip->setDisabled(false);
  46.         leport->setDisabled(false);
  47.         btstart->setText("START");
  48.     }
  50.     void recv_show()
  51.     {
  52.         if(readsize){ //接收图片大小
  53.             char buf[10] = {0};
  54.             sockv->read(buf, 10);
  55.             picsize = atoi(buf); //转成整形大小值
  56.      //       qDebug()<<picsize;
  58.             readsize = false;
  59.         }
  60.         else
  61.         {
  62.             if(sockv->bytesAvailable() < picsize) //等待图片内容接收完整
  63.                 return;
  65.             char buf[640*480*3];
  66.             sockv->read(buf, picsize);
  67.             QPixmap pix;
  68.             pix.loadFromData((uchar*)buf, picsize, "jpeg");
  69.             lbvideo->setPixmap(pix);//切换照片
  71.             readsize = true;
  72.         }
  74.     }
  76. private:
  77.     QLabel *lbvideo, *lbip, *lbport;
  78.     QLineEdit *leip, *leport;
  79.     QPushButton *btstart;
  81.     QTcpSocket *sockv;
  83.     bool readsize;
  84.     int picsize;
  86. };
  88. #endif // WIDGET_H
  1. #include "widget.h"
  2. #include <QHBoxLayout>
  3. #include <QVBoxLayout>
  5. Widget::Widget(QWidget *parent)
  6.     : QWidget(parent)
  7. {
  8.     lbvideo = new QLabel;
  9.     lbvideo->setFixedSize(640,480);
  10.     lbvideo->setScaledContents(true);
  11.     lbip = new QLabel("IP");
  12.     lbport = new QLabel("PORT");
  14.     leip = new QLineEdit("192.168.3.27");
  15.     leport = new QLineEdit("8888");
  17.     btstart = new QPushButton("START");
  19.     QHBoxLayout *hbox = new QHBoxLayout;
  20.     hbox->addWidget(lbip);
  21.     hbox->addWidget(leip);
  22.     hbox->addWidget(lbport);
  23.     hbox->addWidget(leport);
  24.     hbox->addWidget(btstart);
  26.     QVBoxLayout *vbox = new QVBoxLayout;
  27.     vbox->addLayout(hbox);
  28.     vbox->addWidget(lbvideo);
  30.     setLayout(vbox);
  32.     connect(btstart, SIGNAL(clicked()), this, SLOT(startv()));
  33. }
  35. Widget::~Widget()
  36. {
  38. }

服务器：

  1. #ifndef WIDGET_H
  2. #define WIDGET_H
  4. #include <QWidget>
  5. #include <QCamera>
  6. #include <QCameraViewfinder>
  7. #include <QCameraImageCapture>
  8. #include <QLabel>
  9. #include <QTimerEvent>
  10. #include <QDebug>
  11. #include <QPixmap>
  12. #include <QTcpServer>
  13. #include <QTcpSocket>
  14. #include <QTemporaryFile>
  15. #include <QFile>
  16. #include <QBuffer>
  18. class Widget : public QWidget
  19. {
  20.     Q_OBJECT
  22. public:
  23.     Widget(QWidget *parent = 0);
  24.     ~Widget();
  25. public slots:
  26.     void show_pic(int i, QImage img)
  27.     {
  29.         QPixmap pix(1920, 1080);
  30. #if 1
  31.         pix.fill(Qt::red);
  32.         pix = pix.fromImage(img);
  33.         lb_pic->setPixmap(pix);
  34. #else
  35.         lb_pic->setPixmap(QPixmap::fromImage(img));
  37. #endif
  38. //        qDebug()<<i;
  40.         if(client&&client->isWritable())
  41.         {
  42. //            qDebug()<<"sending "<<pix.size();
  43. #if 0
  44.             pix.save("tem.jpg","jpeg");
  45. //             qDebug()<<"saveed";
  46.             QFile tem("tem.jpg");
  47.             tem.open(QIODevice::ReadOnly);
  49. #else
  50.             QBuffer tem;
  51.             pix.save(&tem, "jpeg");
  52. #endif
  53.             char buf[10] = {0};
  54.  //           qDebug()<<"size: "<<buf;
  55.             sprintf(buf, "%d", tem.size());
  56.   //          qDebug()<<"size: "<<buf;
  57.             client->write(buf, 10);//发大小（大小值先转换成字符串装在固定的10个字节的buff中发送）
  58.   //          qDebug()<<"size ok";
  59. #if 0
  60.             QByteArray data = tem.readAll();           
  61. #else
  62.             QByteArray data(tem.buffer());
  63. #endif
  64.             client->write(data);//发图片内容
  65.    //          qDebug()<<"finish";
  66.              tem.close();
  67.         }
  68.     }
  70.     void accept_client()
  71.     {
  72.         if(NULL != client)
  73.         {
  74.             client->close();
  75.             client->deleteLater();
  76.         }
  77.         client = myserver->nextPendingConnection();
  78.         connect(client, SIGNAL(disconnected()), this, SLOT(client_close()));
  79.     }
  81.     void client_close()
  82.     {
  83.         client->close();
  84.         client->deleteLater();
  85.         client = NULL;
  86.     }
  87. protected:
  88.     virtual void
  89.     timerEvent(QTimerEvent *event)
  90.     {
  91.         imageCapture->capture();
  92. //        qDebug()<<"tttt";
  93.     }
  95.  private:
  96.     QCamera *camera;
  97.     QCameraViewfinder *viewfinder;
  98.     QCameraImageCapture *imageCapture;
  99.     QLabel *lb_pic;
  101.     QTcpServer *myserver;
  102.     QTcpSocket *client;
  103. };
  105. #endif // WIDGET_H
  1. #include "widget.h"
  2. #include <QHBoxLayout>
  3. #include <QHostAddress>
  5. Widget::Widget(QWidget *parent)
  6.     : QWidget(parent)
  7. {
  8.     camera = new QCamera("/dev/video0"); //"/dev/video0" 摄像头设备文件，视情况而定
  9.     viewfinder = new QCameraViewfinder(this);
  10.     viewfinder->setFixedSize(640,480);
  11.     viewfinder->show();
  13.       lb_pic = new QLabel(this);
  14.       myserver = new QTcpServer(this);
  15.       client = NULL;
  17.     camera->setViewfinder(viewfinder);
  18.       QHBoxLayout *hbox = new QHBoxLayout;
  19.         hbox->addWidget(viewfinder);
  20.       hbox->addWidget(lb_pic);
  22.       this->setLayout(hbox);
  24.       imageCapture = new QCameraImageCapture(camera);
  26.       camera->setCaptureMode(QCamera::CaptureStillImage);
  28.       connect(imageCapture, SIGNAL(imageCaptured(int,QImage)), this, SLOT(show_pic(int,QImage)));
  29.       connect(myserver, SIGNAL(newConnection()), this, SLOT(accept_client()));
  31.       this->startTimer(3);
  32.       myserver->listen(QHostAddress::AnyIPv4, 8888);
  33.       camera->start();
  34. }
  36. Widget::~Widget()
  37. {
  39. }

发文不通过只能写点”废话“了。学了一个星期的QT感觉其实不难，就是把一些封装好的类组合起来形成一些图形化界面。感觉还是挺好用，起码和C有相通性，唯一的难点应该在C++的语法上。所以会C++的同学应该更加的得心应手。挺好玩的，等学完驱动试试拿QT开发两个项目练练手。比如电视剧里男主给女主写的那个小猪闹钟，非常可爱以前不知道怎么下手做，学完QT我好像知道应该怎么写了。然后我还想做一个类似于QQ微信这种的聊天工具，可惜还不知道怎么用私网和私网通信。难道和女神之间搞点浪漫的东西还要租两台云服务器嘛，那也太扫兴了。现在这ip都是192.168开头的不能直接通信。听朋友说java有个内网透传技术是干这个的。不知道用C怎么实现。不过服务器我虽然买不起但是我打算自己买点件搭建一个服务器。应该会很有意思。

标签： c++ QT 网络编程
本文转载自: https://blog.csdn.net/qq_52479948/article/details/128824315
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