客户端

mainwindow.h

#ifndef MAINWINDOW_H
#define MAINWINDOW_H

#include <QMainWindow>
#include <QUdpSocket>


QT_BEGIN_NAMESPACE
namespace Ui { class MainWindow; }
QT_END_NAMESPACE

class MainWindow : public QMainWindow
{
    Q_OBJECT

public:
    MainWindow(QWidget *parent = nullptr);
    ~MainWindow();

private:
    Ui::MainWindow *ui;
    QUdpSocket* m_pCSocket;
};
#endif // MAINWINDOW_H

main.cpp

#include "mainwindow.h"

#include <QApplication>

int main(int argc, char *argv[])
{
    QApplication a(argc, argv);
    MainWindow w;
    w.show();
    return a.exec();
}

mainwindow.cpp

#include "mainwindow.h"
#include "ui_mainwindow.h"

MainWindow::MainWindow(QWidget *parent)
    : QMainWindow(parent)
    , ui(new Ui::MainWindow)
{
    ui->setupUi(this);

    m_pCSocket = new QUdpSocket(this);

    //要收消息就得绑定端口
    m_pCSocket->bind(ui->lineEdit_cPort->text().toInt());

    connect(ui->btnSend, &QPushButton::clicked, [=]{
        //发消息
        QString msg = "[client]:" + ui->textEdit_Msg->toPlainText();
        m_pCSocket->writeDatagram(msg.toUtf8(), QHostAddress(ui->lineEdit_sIP->text()),
                                                                                         ui->lineEdit_sPort->text().toInt());
        ui->textEdit_Record->append("[client]:" + msg);
        ui->textEdit_Msg->clear();
    });

    connect(m_pCSocket, &QUdpSocket::readyRead, [=]{
        qint64 len = m_pCSocket->pendingDatagramSize();
        QByteArray array(len, 0);
        m_pCSocket->readDatagram(array.data(), len);
        ui->textEdit_Record->append(array);
    });
}

MainWindow::~MainWindow()
{
    delete ui;
}

服务端

widget.h

#ifndef WIDGET_H
#define WIDGET_H

#include <QWidget>
#include <QUdpSocket>

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;

    QUdpSocket *m_pSSocket;
};
#endif // WIDGET_H

main.cpp

#include "widget.h"

#include <QApplication>

int main(int argc, char *argv[])
{
    QApplication a(argc, argv);
    Widget w;
    w.show();
    return a.exec();
}

widget.cpp

#include "widget.h"
#include "ui_widget.h"

Widget::Widget(QWidget *parent)
    : QWidget(parent)
    , ui(new Ui::Widget)
{
    ui->setupUi(this);

    m_pSSocket = new QUdpSocket(this);
    //要收消息就得绑定端口
    m_pSSocket->bind(ui->lineEdit_sPort->text().toInt());

    connect(ui->btnSend, &QPushButton::clicked, [=]{
        //发消息
        QString msg = "[server]:" + ui->textEdit_Msg->toPlainText();
        m_pSSocket->writeDatagram(msg.toUtf8(), QHostAddress(ui->lineEdit_cIP->text()),ui->lineEdit_cPort->text().toInt());

        ui->textEdit_Record->append("[server]:" + msg);
        ui->textEdit_Msg->clear();
    });

    connect(m_pSSocket, &QUdpSocket::readyRead, [=]{
        qint64 len = m_pSSocket->pendingDatagramSize();
        QByteArray array(len, 0);
        m_pSSocket->readDatagram(array.data(), len);
        ui->textEdit_Record->append(array);
    });
}

Widget::~Widget()
{
    delete ui;
}

界面