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Qt中TCP協議通信詳解_C 語言

作者：碼靈薯 ? 更新時間： 2022-10-17 編程語言

TCP協議是經常使用的通信方式。在QT中做了非常友好的封裝，使用非常方便。

需要添加的模塊：network

Qt中的TCP類：QTcpSocket , QTcpServer

常用函數介紹

連接目標地址和端口

virtual void QTcpSocket ::connectToHost(const QHostAddress &address, quint16 port, OpenMode mode = ReadWrite);

  • 發送數據

inline qint64 QTcpSocket ::write(const QByteArray &data)

  • 監聽某個地址和端口號

bool QTcpServer::listen(const QHostAddress &address = QHostAddress::Any, quint16 port = 0);

  • 有新的連接信號

void QTcpServer::newConnection();

  • 是否有新的連接

virtual bool QTcpServer::hasPendingConnections() const;

  • 獲取新的連接，必須處理完才能繼續接收到連接

virtual QTcpSocket *QTcpServer::nextPendingConnection();

  • 收到新的數據信號

void QTcpSocket::readyRead();

  • 讀取收到的數據，必須讀取完才能繼續接收

QByteArray readAll();

使用案例（example）

客戶端

#include <QTcpSocket>
#include <QWidget>
#include <QLineEdit>
class Client : public QWidget
{
?? ?Q_OBJECT
public:
?? ?Client(QWidget *parent);

public slots:
?? ?void slotSendButtonClick();
private:
?? ?QTcpSocket *_socket;
?? ?QLineEdit *_lineEdit;
?? ?bool _isConnected;
};
#include "client.h"
#include <QPushButton>
#include <QHBoxLayout>
Client::Client(QWidget *parent)
?? ?: QWidget(parent)
{
?? ?_socket = new QTcpSocket(this);

?? ?_lineEdit = new QLineEdit(this);
?? ?QPushButton *sendButton = new QPushButton("send");
?? ?connect(sendButton, SIGNAL(clicked()), this, SLOT(slotSendButtonClick()));
?? ?connect(_lineEdit, SIGNAL(returnPressed()), this, SLOT(slotSendButtonClick()));
?? ?
?? ?QHBoxLayout *lay = new QHBoxLayout(this);
?? ?lay->addWidget(_lineEdit);
?? ?lay->addWidget(sendButton);

?? ?_isConnected = false;
}

void Client::slotSendButtonClick()
{
?? ?if (!_isConnected)
?? ?{
?? ??? ?_socket->connectToHost("127.0.0.1", 9988);
?? ??? ?_isConnected = true;
?? ?}
?? ?QString text = _lineEdit->text();
?? ?if (!text.isEmpty())
?? ?{
?? ??? ?_socket->write(text.toUtf8());//發送數據
?? ??? ?_lineEdit->clear();
?? ?}
}

服務端

#include <QWidget>
#include <QTcpServer>
#include <QTcpSocket>
class QTextBrowser;
class Server :public QWidget
{
?? ?Q_OBJECT
public:
?? ?Server(QWidget *parent);
public slots:
?? ?void slotCurrentIndexChanged(const QString&);
?? ?void slotNewConnection();
private:
?? ?QTcpServer *_server;
?? ?QTcpSocket *_socket;
?? ?QTextBrowser *_textBrowser;
};
#include "server.h"
#include <QHostAddress>
#include <QTextBrowser>
#include <QByteArray>
#include <QGridLayout>
#include <QNetworkInterface>
#include <QComboBox>
Server::Server(QWidget *parent)
{
?? ?_server = new QTcpServer(this);
?? ?//_server->listen(QHostAddress::Any, 9988);//監聽跟本主機相連的所有網口
?? ?connect(_server, SIGNAL(newConnection()),this, SLOT(slotNewConnection()) );

?? ?QList<QHostAddress> addrList = QNetworkInterface::allAddresses();
?? ?QComboBox *comboBox = new QComboBox;
?? ?for (const QHostAddress& addr : addrList)
?? ?{
?? ??? ?quint32 ipAddr = addr.toIPv4Address();
?? ??? ?if (ipAddr != 0)
?? ??? ?{
?? ??? ??? ?comboBox->addItem(QHostAddress(ipAddr).toString());
?? ??? ?}
?? ?}
?? ?connect(comboBox, SIGNAL(currentIndexChanged(const QString&)), this, SLOT(slotCurrentIndexChanged(const QString&)));


?? ?_textBrowser = new QTextBrowser(this);
?? ?QGridLayout *lay = new QGridLayout(this);
?? ?lay->addWidget(comboBox, 0, 0);
?? ?lay->addWidget(_textBrowser,1,0);
}

void Server::slotCurrentIndexChanged(const QString& item)
{
?? ?if (!_server->isListening())
?? ?{
?? ??? ?_server->listen(QHostAddress(item), 9988);
?? ?}
?? ?
?? ?_textBrowser->append("listen...");
}

void Server::slotNewConnection()
{
?? ?_textBrowser->append("connecting...");
?? ?while (_server->hasPendingConnections())//必須處理完所有的連接，否則有新連接時就不會在發信號過來
?? ?{
?? ??? ?_socket = _server->nextPendingConnection();
?? ??? ?connect(_socket, &QTcpSocket::readyRead, [&]() {
?? ??? ??? ?_textBrowser->append("receive message...");
?? ??? ??? ?QByteArray newMessage = _socket->readAll();
?? ??? ??? ?_textBrowser->append(QString(newMessage));
?? ??? ?});
?? ?}
}

使用效果

原文鏈接：https://blog.csdn.net/geduo_feng/article/details/103102856

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