Qt 网络编程实战

一.获取主机的网络信息

1. 需要添加network模块

QT   += core gui network

1. 主要涉及的类分析

QHostInfo类

• QHostInfo::localHostName() 获取本地的主机名
• QHostInfo::fromName(const QString &) 获取指定主机的主机信息 addresses接口

  QNetworkInterface类

  • QNetworkInterface::allAddresses() 网卡所有的IP地址
    1. 项目效果

    

    1. 源码如下

    #ifndef MAINWINDOW_H
    #define MAINWINDOW_H
    #include 
    #include
    QT_BEGIN_NAMESPACE
    namespace Ui { class MainWindow; }
    QT_END_NAMESPACE
    class MainWindow : public QMainWindow
    {
        Q_OBJECT
    public:
        MainWindow(QWidget *parent = nullptr);
        ~MainWindow();
    private slots:
        //获取主机名
        void GetHostName();
        //获取IPV4
        void GetIPV4();
        //获取IPV6
        void GetIPV6();
        //清除文本内容
        void Clear_Text();
        //获取指定域名的IP地址
        void Get_DefineHost();
        void lookedUp(QHostInfo hostInfo);
        //主机所有网卡IP地址
        void GetAlladdresses();
        //所有网卡的网络信息
        void GetNetWorkInfo();
    private:
        void InitConnectSignals();
    private:
        Ui::MainWindow *ui;
    };
    #endif // MAINWINDOW_H
    

    #include "mainwindow.h"
    #include "ui_mainwindow.h"
    #include
    #include
    MainWindow::MainWindow(QWidget *parent)
        : QMainWindow(parent)
        , ui(new Ui::MainWindow)
    {
        ui->setupUi(this);
        this->setWindowTitle("主机的网络信息");
        InitConnectSignals();
    }
    MainWindow::~MainWindow()
    {
        delete ui;
    }
    void MainWindow::GetHostName()
    {
        //获取当前的主机名
        QString hostname = QHostInfo::localHostName();
        ui->textEdit->append("当前的主机名为："+hostname);
    }
    void MainWindow::GetIPV4()
    {
        //获取当前的主机名
        QString hostname = QHostInfo::localHostName();
        //获取指定主机的主机信息
        QHostInfo hostinformation = QHostInfo::fromName(hostname);
        //Returns the list of IP addresses associated with hostName().
        //This list may be empty.
        //返回与hostName()相关联的IP地址列表。
        //该列表可能为空。
        QList addrlist = hostinformation.addresses();
        ui->textEdit->append("本机的IPV4地址如下:");
        if(!addrlist.isEmpty())
        {
            //for遍历输出
            for(int i=0;i
                //protocol是协议的意思
                if(addrlist[i].protocol()==QAbstractSocket::IPv4Protocol)
                {
                    ui-textEdit->append(addrlist[i].toString());
                }
            }
        }
    }
    void MainWindow::GetIPV6()
    {
        //获取当前的主机名
        QString hostname = QHostInfo::localHostName();
        //获取指定主机的主机信息
        QHostInfo hostinformation = QHostInfo::fromName(hostname);
        //Returns the list of IP addresses associated with hostName().
        //This list may be empty.
        //返回与hostName()相关联的IP地址列表。
        //该列表可能为空。
        QList addrlist = hostinformation.addresses();
        ui->textEdit->append("本机的IPV6地址如下:");
        if(!addrlist.isEmpty())
        {
            //for遍历输出
            for(int i=0;i
                //protocol是协议的意思
                if(addrlist[i].protocol()==QAbstractSocket::IPv6Protocol)
                {
                    ui-textEdit->append(addrlist[i].toString());
                }
            }
        }
    }
    void MainWindow::Clear_Text()
    {
        ui->textEdit->clear();
    }
    void MainWindow::Get_DefineHost()
    {
        //获取lineEdit上的域名
        QString hostName =ui->lineEdit->text();
        if(hostName.isEmpty())
        {
            return ;
        }
        //获取域名的IPV4信息
        /*
         查找与主机名name相关联的IP地址，并返回用于查找的ID。当查找结果准备好时，
    将使用QHostInfo参数调用receiver中的slot或信号成员。然后可以检查QHostInfo对象以获得查找结果。
          */
        //lookupHost(const QString &name, QObject *context, Func1 slot)
        QHostInfo::lookupHost(hostName,this,SLOT(lookedUp(QHostInfo)));
    }
    void MainWindow::lookedUp(QHostInfo hostInfo)
    {
        //当前的主机名
        QString hostName=hostInfo.hostName();
        ui->textEdit->append("当前域名为:"+hostName+" IPV4信息如下：");
        QList addrlist = hostInfo.addresses();
        if(!addrlist.isEmpty())
        {
            for(int i=0;i
                if(addrlist[i].protocol()==QAbstractSocket::IPv4Protocol)
                {
                    ui-textEdit->append(addrlist[i].toString());
                }
            }
        }
        /*
          常见的错误
    QObject::connect: Incompatible sender/receiver arguments
            QHostInfoResult::resultsReady(QHostInfo) --> MainWindow::lookedUp(QHostInfo&)
            信号和槽的参数不匹配
         */
    }
    void MainWindow::GetAlladdresses()
    {
        //获取网卡的所有IP信息
        ui->textEdit->append("所有网卡的IPV4信息如下:");
        QListaddrlist = QNetworkInterface::allAddresses();
        if(!addrlist.isEmpty())
        {
            for(int i=0;i
                if(addrlist[i].protocol()==QAbstractSocket::IPv4Protocol)
                {
                    ui-textEdit->append(addrlist[i].toString());
                }
            }
        }
    }
    void MainWindow::GetNetWorkInfo()
    {
        //获取所有网卡的网络信息
        QListlist =QNetworkInterface::allInterfaces();
        for(int i=0;i
            QNetworkInterface interface = list[i];
            if(!interface.isValid())
            {
                continue;
            }
            ui-textEdit->append("设备名称："+interface.humanReadableName());
            ui->textEdit->append("硬件地址："+interface.hardwareAddress());
            //一个网卡，可以有多个IP地址
            QList list2 = interface.addressEntries();
            for(int j=0; j
                  QNetworkAddressEntry entry = list2[j];
                  ui-textEdit->append("\tIP地址：" + entry.ip().toString());
                  ui->textEdit->append("\t子网掩码：" + entry.netmask().toString());
                  ui->textEdit->append("\t广播地址: " + entry.broadcast().toString() + "\n");
             }
        }
    }
    void MainWindow::InitConnectSignals()
    {
        //void pressed();
        connect(ui->pushButton_HostName,SIGNAL(pressed()),this,SLOT(GetHostName()));
        connect(ui->pushButton_IPV4,SIGNAL(pressed()),this,SLOT(GetIPV4()));
        connect(ui->pushButton_IPV6,SIGNAL(pressed()),this,SLOT(GetIPV6()));
        connect(ui->pushButton_Clear,SIGNAL(pressed()),this,SLOT(Clear_Text()));
        connect(ui->pushButton_DefineHost,SIGNAL(pressed()),this,SLOT(Get_DefineHost()));
        connect(ui->pushButton_Alladdresses,SIGNAL(pressed()),this,SLOT(GetAlladdresses()));
        connect(ui->pushButton_Network,SIGNAL(pressed()),this,SLOT(GetNetWorkInfo()));
    }
    

    二.TCP编程

    1. server编程（服务器端实现）

    • 项目效果

      

    • 客户端(使用的是调试助手)

      

    • 项目源码

      #include "mainwindow.h"
      #include "ui_mainwindow.h"
      #include
      #include
      MainWindow::MainWindow(QWidget *parent)
          : QMainWindow(parent)
          , ui(new Ui::MainWindow)
      {
          ui->setupUi(this);
          InitUI();
      }
      MainWindow::~MainWindow()
      {
          delete ui;
      }
      void MainWindow::InitUI()
      {
          //加状态栏中添加控件
          label_first=new QLabel();
          label_second=new QLabel();
          label_third=new QLabel();
          label_four=new QLabel();
          label_first->setText("监听状态:");
          label_third->setText("套接字状态:");
          label_first->setMaximumWidth(80);
          label_third->setMaximumWidth(80);
          label_second->setMinimumWidth(100);
          label_four->setMinimumWidth(100);
          ui->statusbar->addWidget(label_first);
          ui->statusbar->addWidget(label_second);
          ui->statusbar->addWidget(label_third);
          ui->statusbar->addWidget(label_four);
          //fromName 返回指定主机的主机信息
          QHostInfo hostInfo = QHostInfo::fromName(QHostInfo::localHostName());
          QList addrlist = hostInfo.addresses();
          if(!addrlist.isEmpty())
          {
              for(int i=0;i
                  QHostAddress address = addrlist[i];
                  if(address.protocol()==QAbstractSocket::IPv4Protocol)
                  {
                      ui-comboBox->addItem(address.toString());
                  }
              }
          }
          //本机的环回网卡的IP 127.0.0.1
          //用来做网络测试的
          ui->comboBox->addItem("127.0.0.1");
          //处理tcp通信
          tcpserver=new QTcpServer(this);
          //发现新信号就触发onNewConnection
          connect(tcpserver,SIGNAL(newConnection()),this,SLOT(onNewConnection()));
      
      }
      void MainWindow::on_actionListen_triggered()
      {
          QString ip =ui->comboBox->currentText();
          //unsigned short
          quint16 port = ui->spinBox->value();
          QHostAddress addr(ip);
          //开始监听
          tcpserver->listen(addr,port);
          label_second->setText("已开始监听");
          ui->textEdit->append("开始监听,等待客户端发起连接...");
          ui->textEdit->append("服务器地址:"+tcpserver->serverAddress().toString());
          ui->textEdit->append("服务器端口:"+QString::number(tcpserver->serverPort()));
          //更改控件
          ui->actionStop->setEnabled(true);
          ui->actionListen->setEnabled(false);
      }
      void MainWindow::on_actionStop_triggered()
      {
          //停止监听
          if(tcpserver->isListening())
          {
              tcpserver->close();
              ui->actionListen->setEnabled(true);
              ui->actionStop->setEnabled(false);
              label_second->setText("已停止监听");
          }
      }
      void MainWindow::on_actionClear_triggered()
      {
          label_second->clear();
          label_four->clear();
          ui->textEdit->clear();
      }
      void MainWindow::onNewConnection()
      {
          //一旦有新的连接
          //难以理解的概念：套接字,相当于客户端套接字，每当有客户端发起请求，服务器就会分配一个套接字
          //去接待
          tcpsocket=tcpserver->nextPendingConnection();//取出要服务，相当于是分配一个服务人员
          //连接成功会触发的
          connect(tcpsocket,SIGNAL(connected()),this,SLOT(onConnected()));
          //当有数据可以读的时候，我们就读数据，（使用信号槽）
          connect(tcpsocket,SIGNAL(readyRead()),this,SLOT(onSocketReadyRead()));
          connect(tcpsocket,SIGNAL(disconnected()),this,SLOT(onDisconnected()));
          // void stateChanged(QAbstractSocket::SocketState);
          connect(tcpsocket,SIGNAL(stateChanged(QAbstractSocket::SocketState)),
                  this,SLOT(onSocketStateChanged(QAbstractSocket::SocketState)));
          onSocketStateChanged(tcpsocket->state());//先更新一下状态
      }
      void MainWindow::onSocketReadyRead()
      {
          //有数据可读时
          while(tcpsocket->canReadLine())
          {
              ui->textEdit->append("[收到]"+tcpsocket->readLine());
          }
      }
      void MainWindow::onConnected()
      {
          //刚连入成功
          ui->textEdit->append("\n客户端请求已经接入！");
          //获取客户端的地址信息
          ui->textEdit->append("客户端地址："+tcpsocket->peerAddress().toString());
          ui->textEdit->append("客户端端口号："+QString::number(tcpsocket->peerPort()));
      
      }
      void MainWindow::onDisconnected()
      {
          ui->textEdit->append("\n客户端已断开连接");
          tcpsocket->deleteLater();//以后在删除，这样更安全
      }
      void MainWindow::onSocketStateChanged(QAbstractSocket::SocketState status)
      {
          /*
              UnconnectedState,
              HostLookupState,
              ConnectingState,
              ConnectedState,
              BoundState,
              ListeningState,
              ClosingState
           */
          //套接字状态发生变化
          switch(status)
          {
              case QAbstractSocket::UnconnectedState:
              label_four->setText("未连接");
              break;
              case QAbstractSocket::HostLookupState:
              label_four->setText("正在查找主机名");
              break;
              case QAbstractSocket::ConnectingState:
              label_four->setText("正在连接");
              break;
              case QAbstractSocket::ConnectedState:
              label_four->setText("已连接");
              break;
              case QAbstractSocket::BoundState:
              label_four->setText("已绑定到IP地址和端口号");
              break;
              case QAbstractSocket::ListeningState:
              label_four->setText("正在监听");
              break;
              case QAbstractSocket::ClosingState:
              label_four->setText("准备关闭");
              break;
          }
      }
      void MainWindow::on_pushButton_clicked()
      {
          //发送一行字符串
          QString msg = ui->lineEdit->text();
          //utf编码,QByteArray在功能上很像字符数组
          QByteArray str=msg.toUtf8();
          str.append('\n');
          //服务器向客户端发送数据
          tcpsocket->write(str);
      }
      void MainWindow::on_actionQuit_triggered()
      {
          close();
      }
      

      2. 客户端实现

      • 效果展示

        

      • 源码如下

        #include "mainwindow.h"
        #include "ui_mainwindow.h"
        MainWindow::MainWindow(QWidget *parent)
            : QMainWindow(parent)
            , ui(new Ui::MainWindow)
        {
            ui->setupUi(this);
            //创建了客户端的套接字对象
            tcpsocket=new QTcpSocket(this);
            //连接成功会触发的
            connect(tcpsocket,SIGNAL(connected()),this,SLOT(onConnected()));
            //当有数据可以读的时候，我们就读数据，（使用信号槽）
            connect(tcpsocket,SIGNAL(readyRead()),this,SLOT(onSocketReadyRead()));
            connect(tcpsocket,SIGNAL(disconnected()),this,SLOT(onDisconnected()));
            // void stateChanged(QAbstractSocket::SocketState);
            connect(tcpsocket,SIGNAL(stateChanged(QAbstractSocket::SocketState)),
                    this,SLOT(onSocketStateChanged(QAbstractSocket::SocketState)));
            ui->actionConnect->setEnabled(true);
            ui->actionDisconnect->setEnabled(false);
        }
        MainWindow::~MainWindow()
        {
            delete ui;
        }
        void MainWindow::onConnected()
        {
            //peerAddress对等地址
            //打印服务器的地址
            ui->plainTextEdit->appendPlainText("已连接到服务器！");
            ui->plainTextEdit->appendPlainText("---服务器地址："+
                    tcpsocket->peerAddress().toString());
            ui->plainTextEdit->appendPlainText("---服务器端口："+
                                               QString::number(tcpsocket->peerPort()));
        }
        void MainWindow::onDisconnected()
        {
            ui->plainTextEdit->appendPlainText("服务器的连接已经断开");
            ui->actionConnect->setEnabled(true);
            ui->actionDisconnect->setEnabled(false);
        }
        void MainWindow::onSocketStateChanged(QAbstractSocket::SocketState status)
        {
            //这和服务器端的判断一样的
        }
        void MainWindow::onSocketReadyRead()
        {
            while(tcpsocket->canReadLine())
            {
                ui->plainTextEdit->appendPlainText("[收到]"+tcpsocket->readLine());
            }
        }
        void MainWindow::on_actionConnect_triggered()
        {
            QString ip = ui->lineEditIP->text();
            quint16 port=ui->spinBoxPort->value();
            tcpsocket->connectToHost(ip,port);
        }
        void MainWindow::on_actionDisconnect_triggered()
        {
            if(tcpsocket->state()==QAbstractSocket::ConnectedState)
            {
                //从主机那断开
                tcpsocket->disconnectFromHost();
            }
        }
        void MainWindow::closeEvent(QCloseEvent *event)
        {
            if(tcpsocket->state()==QAbstractSocket::ConnectedState)
            {
                //从主机那断开
                tcpsocket->disconnectFromHost();
            }
            event->accept();//不调用这个窗口就不会关闭
            //event->ignore();这个窗口就不关闭
        }
        void MainWindow::on_actionClear_triggered()
        {
            ui->plainTextEdit->clear();
        }
        void MainWindow::on_actionQuit_triggered()
        {
            close();
        }
        void MainWindow::on_pushButton_clicked()
        {
            QString msg = ui->lineEditSend->text();
            QByteArray str=msg.toUtf8();
            str.append('\n');
            tcpsocket->write(str);
            ui->plainTextEdit->appendPlainText("[发送]"+msg);
            ui->lineEditSend->clear();
            ui->lineEditSend->setFocus();//设置光标聚焦
        }