Qt网络通信服务端与客户端学习

Qt网络通信服务端与客户端学习

一、项目概述

本项目基于Qt框架实现了TCP服务端与客户端的基本通信，涵盖连接、消息收发、断开管理等功能，适合初学者系统学习Qt网络模块的实际用法。

二、项目结构

• 52/ 服务端：main.cpp、widget.cpp、widget.h
• 53/ 客户端：main.cpp、widget.cpp、widget.h

三、环境配置

• Qt 5.x及以上
• 启用network、widgets模块
• C++11支持

四、服务端核心代码详解（52目录）

1. main.cpp

#include "widget.h"
#include <QApplication>
int main(int argc, char *argv[])
{
    QApplication a(argc, argv);
    Widget w;
    w.show();
    return a.exec();
}

2. widget.h

#ifndef WIDGET_H
#define WIDGET_H
#include <QWidget>
#include <QTcpServer>
#include <QTcpSocket>
QT_BEGIN_NAMESPACE
namespace Ui { class Widget; }
QT_END_NAMESPACE
class Widget : public QWidget
{
    Q_OBJECT
public:
    Widget(QWidget *parent = nullptr);
    ~Widget();
private:
    Ui::Widget *ui;           // UI指针
    QTcpServer *tcpServer;    // TCP服务端对象
private slots:
    void mNewConnetion();     // 新连接处理槽
    void receiveMessages();   // 接收消息槽
    void mStateChanged(QAbstractSocket::SocketState); // 连接状态变化槽
    void on_pushButton_3_clicked(); // 发送消息按钮槽
    void on_pushButton_clicked();   // 开始监听按钮槽
    void on_pushButton_2_clicked(); // 停止监听按钮槽
};
#endif // WIDGET_H

3. widget.cpp

#include "widget.h"
#include "ui_widget.h"
Widget::Widget(QWidget *parent)
    : QWidget(parent)
    , ui(new Ui::Widget)
{
    ui->setupUi(this);
    tcpServer = new QTcpServer(this);
    this->setWindowTitle("服务端");
    connect(tcpServer, SIGNAL(newConnection()), this, SLOT(mNewConnetion()));
    ui->pushButton_2->setEnabled(false);
}
Widget::~Widget()
{
    delete ui;
}
void Widget::mNewConnetion()
{
    QTcpSocket *tmpTcpSocket = tcpServer->nextPendingConnection();
    QString ipaddr = tmpTcpSocket->peerAddress().toString();
    quint16 port = tmpTcpSocket->peerPort();
    ui->textBrowser->append("服务端：客户端的ip地址：" + ipaddr);
    ui->textBrowser->append("服务端：客户端的端口：" + QString::number(port));
    connect(tmpTcpSocket, SIGNAL(readyRead()), this, SLOT(receiveMessages()));
    connect(tmpTcpSocket, SIGNAL(stateChanged(QAbstractSocket::SocketState)),
            this, SLOT(mStateChanged(QAbstractSocket::SocketState)));
}
void Widget::receiveMessages()
{
    QTcpSocket *tmpTcpSocket = (QTcpSocket *)sender();
    ui->textBrowser->append("客户端：" + tmpTcpSocket->readAll());
}
void Widget::mStateChanged(QAbstractSocket::SocketState state)
{
    QTcpSocket *tmpTcpSocket = (QTcpSocket *)sender();
    switch (state) {
    case QAbstractSocket::UnconnectedState:
        ui->textBrowser->append("服务端：客户端断开连接");
        tmpTcpSocket->deleteLater();
        break;
    case QAbstractSocket::ConnectedState:
        ui->textBrowser->append("服务端：客户端已连接");
        break;
    default:
        break;
    }
}
void Widget::on_pushButton_3_clicked()
{
    QList <QTcpSocket *> socketList = tcpServer->findChildren<QTcpSocket *>();
    qDebug() << "tcpSocket 数量：" << socketList.count() << endl;
    if (socketList.count() == 0) {
        ui->textBrowser->append("当前没有客户端连接，请先与客户端连接！");
        return;
    }
    foreach (QTcpSocket *tmpTcpSocket, socketList) {
        tmpTcpSocket->write(ui->lineEdit->text().toUtf8());
    }
    ui->textBrowser->append("服务端：" + ui->lineEdit->text());
}
void Widget::on_pushButton_clicked()
{
    tcpServer->listen(QHostAddress("192.168.1.59"), 9999);
    ui->textBrowser->append("服务端:监听的ip地址和端口：192.168.1.59，9999");
    ui->pushButton_2->setEnabled(true);
    ui->pushButton->setEnabled(false);
}
void Widget::on_pushButton_2_clicked()
{
    tcpServer->close();
    ui->pushButton->setEnabled(true);
    ui->pushButton_2->setEnabled(false);
}

五、客户端核心代码详解（53目录）

1. main.cpp

#include "widget.h"
#include <QApplication>
int main(int argc, char *argv[])
{
    QApplication a(argc, argv);
    Widget w;
    w.show();
    return a.exec();
}

2. widget.h

#ifndef WIDGET_H
#define WIDGET_H
#include <QWidget>
#include <QTcpSocket>
#include <QHostAddress>
QT_BEGIN_NAMESPACE
namespace Ui { class Widget; }
QT_END_NAMESPACE
class Widget : public QWidget
{
    Q_OBJECT
public:
    Widget(QWidget *parent = nullptr);
    ~Widget();
private:
    Ui::Widget *ui;           // UI指针
    QTcpSocket *tcpSocket;    // TCP客户端对象
private slots:
    void receiveMessages();   // 接收消息槽
    void mStateChanged(QAbstractSocket::SocketState); // 连接状态变化槽
    void on_pushButton_3_clicked(); // 发送消息按钮槽
    void on_pushButton_clicked();   // 连接服务端按钮槽
    void on_pushButton_2_clicked(); // 断开连接按钮槽
};
#endif // WIDGET_H

3. widget.cpp

#include "widget.h"
#include "ui_widget.h"
Widget::Widget(QWidget *parent)
    : QWidget(parent)
    , ui(new Ui::Widget)
{
    ui->setupUi(this);
    this->setWindowTitle("客户端");
    ui->pushButton_2->setEnabled(false);
    tcpSocket = new QTcpSocket(this);
    connect(tcpSocket, SIGNAL(readyRead()), this, SLOT(receiveMessages()));
    connect(tcpSocket, SIGNAL(stateChanged(QAbstractSocket::SocketState)), this, SLOT(mStateChanged(QAbstractSocket::SocketState)));
}
Widget::~Widget()
{
    delete ui;
}
void Widget::receiveMessages()
{
    ui->textBrowser->append("服务端：" + tcpSocket->readAll());
}
void Widget::mStateChanged(QAbstractSocket::SocketState state)
{
    switch (state) {
    case QAbstractSocket::UnconnectedState:
        ui->textBrowser->append("客户端：与服务端断开连接");
        ui->pushButton->setEnabled(true);
        ui->pushButton_2->setEnabled(false);
        break;
    case QAbstractSocket::ConnectedState:
        ui->textBrowser->append("客户端：已连接服务端");
        ui->pushButton->setEnabled(false);
        ui->pushButton_2->setEnabled(true);
        break;
    default:
        break;
    }
}
void Widget::on_pushButton_3_clicked()
{
    if (tcpSocket->state() == QAbstractSocket::ConnectedState) {
        tcpSocket->write(ui->lineEdit->text().toUtf8());
        ui->textBrowser->append("客户端：" + ui->lineEdit->text());
    } else
        ui->textBrowser->append("请先与服务端连接！");
}
void Widget::on_pushButton_clicked()
{
    ui->textBrowser->append("客户端:监听的ip地址和端口：192.168.1.59，9999");
    tcpSocket->connectToHost(QHostAddress("192.168.1.59"), 9999);
}
void Widget::on_pushButton_2_clicked()
{
    tcpSocket->disconnectFromHost();
}