UDP

广播组

客户端1

widget.h

#ifndef WIDGET_H
#define WIDGET_H
#include <QWidget>
#include <QUdpSocket> //UDP套接字
namespace Ui {
class Widget;
}
class Widget : public QWidget
{
    Q_OBJECT
public:
    explicit Widget(QWidget *parent = 0);
    ~Widget();
    void dealMsg(); // 槽函数，处理对方发送过来的数据
private slots:
    void on_buttonSend_clicked();
private:
    Ui::Widget *ui;
    QUdpSocket *udpSoket; //UDP套接字
};
#endif // WIDGET_H

widget.cpp

#include "widget.h"
#include "ui_widget.h"
#include <QHostAddress>
Widget::Widget(QWidget *parent) :
    QWidget(parent),
    ui(new Ui::Widget)
{
    ui->setupUi(this);
    // 分配空间,指定父对象
    udpSoket = new QUdpSocket(this);
    // 绑定
//    udpSoket->bind(8888);
    udpSoket->bind(QHostAddress::AnyIPv4, 8888); // 如果用了组播就要用IPV4
    // 加入某个组播 组播的地址是D类地址
    udpSoket->joinMulticastGroup(QHostAddress("224.0.0.2"));
    this->setWindowTitle("服务器端口为：8888");
    // 当对方成功发送过来，自动触发readyRead()
    connect(udpSoket, &QUdpSocket::readyRead, this, &Widget::dealMsg);
}
Widget::~Widget()
{
    delete ui;
}
void Widget::dealMsg()
{
    // 读取对方发送过来的内容
    char buf[1024] = {0};
    // 对方地址
    QHostAddress cliAddr;
    // 对方端口
    quint16 port;
    qint64 len = udpSoket->readDatagram(buf, sizeof(buf), &cliAddr, &port);
    if(len > 0)
    {
        // 格式化 [192.68.2.2:8888]aaa
        QString str = QString("[%1:%2] %3")
                .arg(cliAddr.toString())
                .arg(port)
                .arg(buf);
        // 给编辑区设置内容
        ui->textEdit->setText(str);
    }
}
// 发送按钮
void Widget::on_buttonSend_clicked()
{
    // 先获取对方的IP和端口
    QString ip = ui->lineEditIP->text();
    qint16 port = ui->lineEditPort->text().toInt();
    // 获取编辑器内容
    QString str = ui->textEdit->toPlainText();
    // 给指定的IP发送数据
    udpSoket->writeDatagram(str.toUtf8(), QHostAddress(ip), port);
}

客户端2

client.h

#ifndef CLIENT_H
#define CLIENT_H
#include <QWidget>
#include <QUdpSocket>
namespace Ui {
class client;
}
class client : public QWidget
{
    Q_OBJECT
public:
    explicit client(QWidget *parent = 0);
    ~client();
    void Mess();
private slots:
    void on_buttonSend_clicked();
private:
    Ui::client *ui;
    QUdpSocket * udpSocket;
};
#endif // CLIENT_H

client.cpp

#include "client.h"
#include "ui_client.h"
#include <QHostAddress>
client::client(QWidget *parent) :
    QWidget(parent),
    ui(new Ui::client)
{
    ui->setupUi(this);
    this->setWindowTitle("端口号9991");
    udpSocket = new QUdpSocket(this);
    udpSocket->bind(9991);
    connect(udpSocket, &QUdpSocket::readyRead, this, &client::Mess);
}
client::~client()
{
    delete ui;
}
void client::Mess()
{
    char buf[1024] = {0};
    QHostAddress addre;
    quint16 port;
    qint64 leng = udpSocket->readDatagram(buf, sizeof(buf), &addre, &port);
    if(leng>0) {
        QString str = QString("[%1:%2] %3")
                .arg(addre.toString())
                .arg(port)
                .arg(buf);
        ui->textEdit->setText(str);
    }
}
void client::on_buttonSend_clicked()
{
    QString ip = ui->lineEditIP->text();
    qint16 port = ui->lineEditPort->text().toInt();
    QString text = ui->textEdit->toPlainText();
    // 给指定的IP发送数据
    udpSocket->writeDatagram(text.toUtf8(), QHostAddress(ip), port);
}