QT中的TCP通訊伺服器端程式

阿新 • • 發佈：2020-12-30

技術標籤：Qt書籍學習總結 qt tcpip 網路通訊

文章目錄

前言
TCP伺服器端程式設計

前言

本篇文章完成了TCP伺服器端的程式，程式中用到的系統函式，和自定義函式都進行了註釋，如果大家有什麼地方不懂可

以私信我。

完整程式和客戶端介紹在文章結尾有連結,具體功能如下：

TcpServer端：

- 根據指定IP地址和埠開啟網路監聽，有客戶端連線時建立socket連線

- 採用基於行的資料通訊協議，可以接收客戶端發的訊息，也可以向客戶端傳送訊息

- 在狀態列顯示伺服器監聽狀態和socket狀態

效果圖：
在這裡插入圖片描述

TCP伺服器端程式設計

獲取本地IPV4地址

QString TcpClient::getLocalIp()
{
    //返回主機名
    QString hostname = QHostInfo::localHostName();

    //返回主機資訊
    QHostInfo hostInfo = QHostInfo::fromName(hostname);

    //返回IP地址列表
    QList<QHostAddress> addList = hostInfo.addresses();

    QString  localIP= 
"";

    //判斷IP地址列表是否為空
    if(!addList.isEmpty())
    //遍歷IP地址列表，輸出主機資訊
    for(int i=0;i<addList.count();i++)
    {
        QHostAddress aHost = addList.at(i);
        //輸出IPV4資訊
        if(QAbstractSocket::IPv4Protocol==aHost.protocol())
        {
            localIP= aHost.toString();
            break 
;
        }
    }
    return localIP;
}

滑鼠點選槽函式程式

1.開始監聽

作為TCP伺服器，QTcpServer類通過呼叫listen()在本機IP地址和埠上開始TCP監聽，以等待TCP客戶端的接入。

TcpServer::on_actStartListen_triggered()
{
    QString IP = ui->comboBox->currentText();
    quint16 port = ui->spinBox->value();
    QHostAddress addr(IP);
    tcpServer->listen(addr,port);
    //tcpServer->listen(QHostAddress::LocalHost,port);
    ui->plainTextEdit->appendPlainText("Start Listen:");
    ui->plainTextEdit->appendPlainText("伺服器Address: "+tcpServer->serverAddress().toString());
    ui->plainTextEdit->appendPlainText("伺服器Port:    "+QString::number(tcpServer->serverPort()));
    LabListen->setText("Listen State: Start Listen");
}

2.停止監聽

void TcpServer::on_actStopListen_triggered()
{
    //isListening():判斷伺服器是否處於監聽狀態
    if(tcpServer->isListening())
    {
        //close():關閉伺服器，停止網路監聽
        tcpServer->close();
        LabListen->setText("Listen State: Stop Listen");
    }
}

3.清空文字

void TcpServer::on_actClear_triggered()
{
    ui->plainTextEdit->clear();
}

4.傳送按鈕

void TcpServer::on_btnSend_clicked()
{
    QString msg = ui->lineEdit->text();
    ui->plainTextEdit->appendPlainText("[out]: "+msg);
    ui->lineEdit->clear();
    ui->lineEdit->setFocus();


    QByteArray str = msg.toUtf8();
    str.append('\n');
    tcpSocket->write(str);
}

其他槽函式程式

1.建立新連線

void TcpServer::onNewConnection()
{  
   tcpSocket = tcpServer->nextPendingConnection();//獲取接入連線的socket
   //第一次連線，手動呼叫客戶連線槽函式
   onClientConnected();
   connect(tcpSocket,SIGNAL(connected()),this,SLOT(onClientConnected()));
   connect(tcpSocket,SIGNAL(disconnected()),this,SLOT(onClientDisconnected()));
   connect(tcpSocket,SIGNAL(stateChanged(QAbstractSocket::SocketState)),this,\
           SLOT(onStateChange(QAbstractSocket::SocketState)));
   onStateChange(tcpSocket->state());
   connect(tcpSocket,SIGNAL(readyRead()),this,SLOT(onSocketReadyRead()));
}

2.開始連線

void TcpServer::onClientConnected()
{
    ui->plainTextEdit->appendPlainText("Client Socket Connected");
    ui->btnSend->setEnabled(true);

    //peerAddress():在已連線狀態下，返回對方socket的地址
    ui->plainTextEdit->appendPlainText("Peer Address: "+tcpSocket->peerAddress().toString());

    //peerPort():在已連線狀態下，返回對方socket的埠
    ui->plainTextEdit->appendPlainText("Peer Port:    "+QString::number(tcpSocket->peerPort()));
}

3.斷開連線

void TcpServer::onClientDisconnected()
{
    ui->plainTextEdit->appendPlainText("Client Socket Disconnected");

    //deleteLater():刪除一個物件時，依賴此物件的子物件都會被刪除，減少記憶體洩漏的風險
    tcpSocket->deleteLater();
}

4.實現緩衝區資料的讀取

void TcpServer::onSocketReadyRead()
{
    //canReadLine():判斷是否有新的一行資料需要讀取
    while(tcpSocket->canReadLine())
    {
        //readLine():讀取一行資料
        ui->plainTextEdit->appendPlainText("[in] "+tcpSocket->readLine());
    }
}

5.socket狀態改變

void TcpServer::onStateChange(QAbstractSocket::SocketState socketState)
{
    switch(socketState)
    {
    case QAbstractSocket::UnconnectedState:
        LabSocketState->setText("Socket State: UnconnectedState"); break;
    case QAbstractSocket::HostLookupState:
        LabSocketState->setText("Socket State: HostLookupState"); break;
    case QAbstractSocket::ConnectingState:
        LabSocketState->setText("Socket State: ConnectingState"); break;
    case QAbstractSocket::ConnectedState:
        LabSocketState->setText("Socket State: ConnectedState"); break;
    case QAbstractSocket::BoundState:
        LabSocketState->setText("Socket State: BoundState"); break;
    case QAbstractSocket::ClosingState:
        LabSocketState->setText("Socket State: ClosingState"); break;
    case QAbstractSocket::ListeningState:
        LabSocketState->setText("Socket State: ListeningState"); break;
    }
}