1. UDP通信概述
UDP是无连接、不可靠、面向数据报(datagram)的协议,可以应用于对可靠性要求不高的场合。与TCP通信不同,UDP通信无需预先建立持久的socket连接,UDP每次发送数据报都需要指定目标地址和端口。
QUdpSocket以数据报传输数据,而不是以连续的数据流。发送数据报使用函数 QUdpSocket::writeDatagram(),数据报的长度一般少于512字节,每个数据报包含发送者和接收者的IP地址和端口等信息。
UDP数据接收,首先要使用QUdpSocket::bind()绑定一个端口,绑定端口后,socket的状态会变为已绑定状态“BoundState”。
当有数据报传入时,QudpSocket会自动发射readyRead()信号,在其槽函数中使用QUdpSocket::readDatagram()进行数据读取。abort()为解除绑定,解除后socket状态变为未连接状态“UnconnectedState”。
2. UDP消息传送的三种模式
单播模式(unicast):一个UDP客户端发送数据报到指定地址和端口的另一UDP客户端,是一对一的数据传输。
广播模式(broadcast):一个UDP客户端发出的数据报,在同一网络范围内其他所有的UDP客户端都可以收到。QUdpSocket支持IPv4广播。需要在数据报中指定接收端地址为QHostAddress::Broadcast,一般的广播地址是255.255.255.255。
组播模式(multicast):UDP客户端加入到另一个组播IP地址的多播组,成员向组播地址发送的数据报,其加入组播的所有成员都可以接收到,类似于QQ群功能。QUdpSocket::joinMulticastGroup()函数实现加入多播组的功能。
QUdpSocket::leaveMulticastGroup()函数实现
在单播、广播和多播模式下,UDP程序都是对等的,不像TCP通信分为客户端和服务端。
TCP通信只有单播模式。UDP通信虽然不能保证数据传输的准确性,但是具有灵活性,一般的即时通信软件都是基于UDP通信的。
3. QUdpSocket类的接口函数
bool bind(quint16 port = 0) 为UDP通信绑定一个端口
qint64 writeDatagram(QByteArray& datagram, QHostAddress& host, quint16 port) 向目标地址和端口的UDP客户端发送数据报,返回成功发送的字节数,数据报的长度一般不超过512字节。
bool hasPendingDatagrams() 当至少有一个数据报需要读取时,返回true
qint64 pendingDatagramSize() 返回第一个待读取的数据报的大小
qint64 readDatagram(char* data, qint64 maxSize) 读取一个数据报,返回成功读取的字节数
qint64 readDatagram(char* data, qint64 maxSize, QHostAddress* address, quint16* port) 读取一个数据报,返回成功读取的字节数。发送方的主机地址和端口存储在*address和*port中(除非指针为0)
bool joinMulticastGroup(QHostAddress& groupAddress) 加入一个多播组
bool leaveMulticastGroup(QHostAddress& groupAddress) 离开一个多播组
void abort() 终止当前连接并重置套接字。通常在析构函数中写入。与disconnectFromHost()不同,该函数立即关闭套接字,丢弃写入缓冲区中的任何挂起数据。
原文链接:https://blog.csdn.net/WL0616/article/details/129050373
4.UDP对话小案例
实现发送和接收端互相发信息,类似QQ (界面使用UI设计)
4.1.接收端
receiver.h
#ifndef RECESIVER_H
#define RECESIVER_H
#include <QWidget>
#include <QUdpSocket>
QT_BEGIN_NAMESPACE
namespace Ui { class Recesiver; }
QT_END_NAMESPACE
class Recesiver : public QWidget
{
Q_OBJECT
public:
Recesiver(QWidget *parent = nullptr);
~Recesiver();
private slots:
void on_pushButton_2_clicked(); //启动槽函数
void start();
void on_pushButton_clicked();
private:
Ui::Recesiver *ui;
QUdpSocket *receiver;
};
#endif // RECESIVER_H
receiver.cpp
#include "recesiver.h"
#include "ui_recesiver.h"
Recesiver::Recesiver(QWidget *parent)
: QWidget(parent)
, ui(new Ui::Recesiver)
{
ui->setupUi(this);
setWindowTitle(QStringLiteral("接收端"));
ui->lineEdit->setText("127.0.0.1");
receiver =new QUdpSocket(this);
}
Recesiver::~Recesiver()
{
delete ui;
}
//接收信息
void Recesiver::start()
{
QByteArray datagram;
datagram.resize(receiver->pendingDatagramSize()); //接收到的数据的长度
receiver->readDatagram(datagram.data(),datagram.size());
ui->textEdit->append(QStringLiteral("对方:")+datagram);
}
//启动按钮(发送端发送信息给接收端)
void Recesiver::on_pushButton_2_clicked()
{
receiver->bind(ui->lineEdit_2->text().toInt());//设置端口号将其转为整型
connect(receiver,&QUdpSocket::readyRead,this,[&](){start();});
ui->pushButton_2->setEnabled(false);
ui->lineEdit_2->setEnabled(false);
}
//发送按钮(接收端发送信息给发送端)
void Recesiver::on_pushButton_clicked()
{
QByteArray datagram=ui->textEdit_2->toPlainText().toUtf8(); //在输入端输入发送的内容
receiver->writeDatagram(datagram.data(),datagram.size(),QHostAddress(ui->lineEdit->text()),ui->lineEdit_3->text().toInt());
//qint64 writeDatagram(const char *data, qint64 len, const QHostAddress &host, quint16 port);
//发送数据,大小,发送主机的ip,发送主机的端口号
ui->textEdit->append(QStringLiteral("本机:")+ui->textEdit_2->toPlainText());//发送信息的具体内容在发送端的聊天记录里能体现
ui->textEdit_2->clear();
}
4.2发送端
sender.h
#ifndef SENDER_H
#define SENDER_H
#include <QWidget>
#include <QUdpSocket>
QT_BEGIN_NAMESPACE
namespace Ui { class Sender; }
QT_END_NAMESPACE
class Sender : public QWidget
{
Q_OBJECT
public:
Sender(QWidget *parent = nullptr);
~Sender();
void start2();
private slots:
void on_pushButton_clicked();
private:
Ui::Sender *ui;
QUdpSocket *sender;
};
#endif // SENDER_H
sender.cpp
#include "sender.h"
#include "ui_sender.h"
Sender::Sender(QWidget *parent)
: QWidget(parent)
, ui(new Ui::Sender)
{
ui->setupUi(this);
sender=new QUdpSocket(this);
setWindowTitle(QStringLiteral("发送端"));
//sender
ui->lineEdit_3->setText("888");
sender->bind(ui->lineEdit_3->text().toInt());//绑定端口号
connect(sender,&QUdpSocket::readyRead,this,[&](){start2();});
//start2();
}
void Sender::start2()
{
QByteArray datagram;
datagram.resize(sender->pendingDatagramSize()); //接收到的数据的长度
sender->readDatagram(datagram.data(),datagram.size());
ui->textEdit->append(QStringLiteral("对方:")+datagram);
}
Sender::~Sender()
{
delete ui;
}
//发送按钮 发送信息给接收端
void Sender::on_pushButton_clicked()
{
QByteArray datagram=ui->textEdit_2->toPlainText().toUtf8(); //在输入端输入发送的内容
sender->writeDatagram(datagram.data(),datagram.size(),QHostAddress(ui->lineEdit->text()),ui->lineEdit_2->text().toInt());
//qint64 writeDatagram(const char *data, qint64 len, const QHostAddress &host, quint16 port);
//发送数据,大小,发送主机的ip,发送主机的端口号
ui->textEdit->append(QStringLiteral("本机:")+ui->textEdit_2->toPlainText());//发送信息的具体内容在发送端的聊天记录里能体现
ui->textEdit_2->clear();
}
结果:
(ps:对话有点搞笑,哈哈哈)
5.4. UDP单播和广播代码示例
4.1 测试说明
本实例实现UDP通信的单播和广播。两个实例可以运行在同一台计算机上,也可以运行在不同的计算机上。
这里的两个实例是运行在同一台计算机上,需要注意,在同一台计算机上运行时,两个实例需要绑定不同的端口。例如实例A绑定端口1600,实例B绑定端口3200,实例A向实例B发送数据报时,需要指定实例B的端口,这样实例B才能收到数据。
如果两个实例在不同的计算机上运行,则端口可以一样,因为IP地址不同了,不会导致绑定时发生冲突。一般的UDP通信程序都是在不同的计算机上运行的,约定一个固定的端口作为通信端口。
4.2主要程序
用UI设计器件和代码化UI分别设计
ui设计器设计:
.h
#ifndef MAINWINDOW_H
#define MAINWINDOW_H
#include <QMainWindow>
#include <QLabel>
#include <QAbstractSocket>
#include <QUdpSocket>
QT_BEGIN_NAMESPACE
namespace Ui { class MainWindow; }
QT_END_NAMESPACE
class MainWindow : public QMainWindow
{
Q_OBJECT
public:
MainWindow(QWidget *parent = nullptr);
~MainWindow();
void handleEvents(); // 信号与槽处理
private:
Ui::MainWindow *ui;
QUdpSocket *udpScoket;
QLabel *labstateScoket; //Scoket状态栏标签
QString getLocalIp(); //获取本机的IP地址
private slots:
void slotActBindPort(); //绑定端口
void slotActUnbindPort(); //解除端口
void slotActClearText(); //清空文本框
void slotActQuit(); //退出
void slotSocketReadyRead(); //读取socket传入的数据
void slotSocketStateChanged(QAbstractSocket::SocketState socketState);
void on_pushButton_clicked(); //发送信息
void on_pushButton_2_clicked(); //广播信息
};
#endif // MAINWINDOW_H
.cpp
#include "mainwindow.h"
#include "ui_mainwindow.h"
#include <QTextEdit>
#include <QMessageBox>
#include <QHostInfo>
#include <QAction>
#include <QPushButton>
MainWindow::MainWindow(QWidget *parent)
: QMainWindow(parent)
, ui(new Ui::MainWindow)
{
ui->setupUi(this);
QString localIP = getLocalIp(); //获取本机的IP地址
this->setWindowTitle(this->windowTitle() + "---IP:" + localIP);
ui->comboBox->addItem(localIP); //在目标地址中添加IP
udpScoket = new QUdpSocket(this);
//状态栏
labstateScoket = new QLabel(QStringLiteral("socket状态:"), this);
labstateScoket->setMinimumWidth(150);
ui->statusBar->addWidget(labstateScoket);
handleEvents();
ui->spinBox->setMinimum(1); //设置绑定端口的最大最小值和当前的端口值
ui->spinBox->setMaximum(65535);
ui->spinBox->setValue(1600);
ui->spinBox_2->setMinimum(1); //设置目标端口的最大最小值和当前的端口值
ui->spinBox_2->setMaximum(65535);
ui->spinBox_2->setValue(3200);
}
MainWindow::~MainWindow()
{
udpScoket->abort();
delete udpScoket;
udpScoket = nullptr;
delete ui;
}
// 信号与槽处理
void MainWindow::handleEvents()
{
connect(ui->action, &QAction::triggered, this, &MainWindow::slotActBindPort );
connect(ui->action_2, &QAction::triggered, this, &MainWindow::slotActUnbindPort);
connect(ui->action_3, &QAction::triggered, this, &MainWindow::slotActClearText);
connect(ui->action_4, &QAction::triggered, this, &MainWindow::slotActQuit);
connect(ui->pushButton, &QPushButton::clicked, this, &MainWindow::on_pushButton_clicked);
connect(ui->pushButton_2, &QPushButton::clicked, this, &MainWindow::on_pushButton_2_clicked);
connect(udpScoket, &QUdpSocket::stateChanged, this, &MainWindow::slotSocketStateChanged);
connect(udpScoket, &QUdpSocket::readyRead, this, &MainWindow::slotSocketReadyRead);
}
QString MainWindow::getLocalIp()
{
QString hostName = QHostInfo::localHostName();//获取本机主机名
QHostInfo hostInfo = QHostInfo::fromName(hostName); //返回主机名的IP地址
QString localIP = "";
QList<QHostAddress> addrList = hostInfo.addresses(); //主机IP地址列表
if (!addrList.isEmpty())
{
for (int i = 0; i < addrList.size(); i++)
{
QHostAddress addr = addrList.at(i);
if (QAbstractSocket::IPv4Protocol == addr.protocol())
{
localIP = addr.toString();
break;
}
}
}
return localIP;
}
//绑定端口
void MainWindow::slotActBindPort()
{
quint16 port=ui->spinBox->value(); //绑定本机UDp端口
if(udpScoket->bind(port))
{
ui->textEdit->append(QStringLiteral("**已经绑定成功"));
ui->textEdit->append(QStringLiteral("**绑定端口:")+QString::number(udpScoket->localPort()));
ui->action->setEnabled(false); //开始绑定失效
ui->action_2->setEnabled(true);//解除绑定使能
}
else
ui->textEdit->append(QStringLiteral("绑定失败"));
}
//解除端口
void MainWindow::slotActUnbindPort()
{
udpScoket->abort();//解除绑定
ui->action->setEnabled(true); //开始绑定失效
ui->action_2->setEnabled(false);//解除绑定使能
ui->textEdit->append(QStringLiteral("**已经解除绑定"));
}
//清空文本框
void MainWindow::slotActClearText()
{
ui->textEdit->clear();
}
//退出
void MainWindow::slotActQuit()
{
QMessageBox::StandardButton button = QMessageBox::question(this, "", QStringLiteral("是否要退出?"));
if (button == QMessageBox::StandardButton::Yes)
this->close();
}
//读取socket传入的数据
void MainWindow::slotSocketReadyRead()
{
while(udpScoket->hasPendingDatagrams()) //当有数据传入数据报
{
QByteArray datagtam;
datagtam.resize(udpScoket->pendingDatagramSize());//读取数据报大小
QHostAddress peerAddr; //在已连接的状态下,返回对方的socket的地址
quint16 peerPort; //在已连接的状态下,返回对方的socket的端口
udpScoket->readDatagram(datagtam.data(),datagtam.size(),&peerAddr,&peerPort);//读取数据报的内容
//qint64 readDatagram(char *data, qint64 maxlen, QHostAddress *host = nullptr, quint16 *port = nullptr);
QString str=datagtam.data();
QString peer="[From "+peerAddr.toString()+":"+QString::number(peerPort)+"]";
ui->textEdit->append( peer + str);
}
}
//状态栏显示Socket变化情况
void MainWindow::slotSocketStateChanged(QAbstractSocket::SocketState socketState)
{
switch (socketState)
{
case QAbstractSocket::UnconnectedState: labstateScoket->setText(QStringLiteral("socket状态:UnconnectedState")); break;
case QAbstractSocket::HostLookupState: labstateScoket->setText(QStringLiteral("socket状态:HostLookupState")); break;
case QAbstractSocket::ConnectingState: labstateScoket->setText(QStringLiteral("socket状态:ConnectingState")); break;
case QAbstractSocket::ConnectedState: labstateScoket->setText(QStringLiteral("socket状态:ConnectedState")); break;
case QAbstractSocket::BoundState: labstateScoket->setText(QStringLiteral("socket状态:BoundState")); break;
case QAbstractSocket::ClosingState: labstateScoket->setText(QStringLiteral("socket状态:ClosingState")); break;
default: break;
}
}
//发送信息
void MainWindow::on_pushButton_clicked()
{
QString msg = ui->lineEdit->text(); //发送信息
QByteArray str = msg.toUtf8();
QString targetIp = ui->comboBox->currentText(); //目标IP就是主机地址的ip
QHostAddress targetAddr(targetIp);
quint16 targetPort = ui->spinBox_2->value(); //目标端口
udpScoket->writeDatagram(str, targetAddr, targetPort);//发出数据报
ui->textEdit->append("[out] " + msg);
ui->lineEdit->clear();
ui->lineEdit->setFocus();
}
//广播信息
void MainWindow::on_pushButton_2_clicked()
{
quint16 targetPort = ui->spinBox_2->value(); //目标端口
QString msg=ui->lineEdit->text();
QByteArray str = msg.toUtf8();
udpScoket->writeDatagram(str, QHostAddress::Broadcast, targetPort);//发出数据报
ui->textEdit->append("[broadcast] " + msg);
ui->lineEdit->clear();
ui->lineEdit->setFocus();
}
代码化:
.h
#ifndef MAINWINDOW_H
#define MAINWINDOW_H
#include <QAction>
#include <QComboBox>
#include <QGridLayout>
#include <QHBoxLayout>
#include <QHostInfo>
#include <QLabel>
#include <QLineEdit>
#include <QMainWindow>
#include <QMessageBox>
#include <QPlainTextEdit>
#include <QPushButton>
#include <QSpinBox>
#include <QUdpSocket>
#include <QVBoxLayout>
namespace Ui {
class MainWindow;
}
class MainWindow : public QMainWindow {
Q_OBJECT
public:
explicit MainWindow(QWidget* parent = 0);
~MainWindow();
private slots:
void slotActBindPort();
void slotActUnbindPort();
void slotActClearText();
void slotActQuit();
void slotSocketStateChanged(QAbstractSocket::SocketState socketState);
void slotBtnSend();
void slotBtnBroad();
void slotSocketReadyRead(); //读取socket传入的数据
private:
Ui::MainWindow* ui;
QAction* m_pActBindPort;
QAction* m_pActUnbindPort;
QAction* m_pActClearText;
QAction* m_pActQuit;
QWidget* m_pCentralWidget;
QLabel* m_pLabBindPort;
QLabel* m_PLabTargetAddr;
QLabel* m_pLabTargetPort;
QSpinBox* m_pSpinBindPort;
QComboBox* m_pComboTargetAddr;
QSpinBox* m_pSpinTargetPort;
QLineEdit* m_pLineEdit;
QPushButton* m_pBtnSend;
QPushButton* m_pBtnBroad;
QPlainTextEdit* m_pPlainText;
QLabel* m_pLabState;
QUdpSocket* m_pUdpSocket;
QString getLocalIP();
};
#endif // MAINWINDOW_H
.cpp
#include "mainwindow.h"
#include <QToolBar>
#include "ui_mainwindow.h"
MainWindow::MainWindow(QWidget* parent) : QMainWindow(parent), ui(new Ui::MainWindow) {
ui->setupUi(this);
//this->setWindowIcon(QIcon(":/new/prefix1/res/TitleIcon.png"));
this->setWindowTitle(QStringLiteral("UDP Send/Receiver"));
//工具栏
ui->toolBar->setToolButtonStyle(Qt::ToolButtonTextBesideIcon);
m_pActBindPort = new QAction(QIcon(":/new/Check.png"), QStringLiteral("绑定端口"), this);
m_pActUnbindPort = new QAction(QIcon(":/new/Break.png"), QStringLiteral("结束绑定"), this);
m_pActClearText = new QAction(QIcon(":/new/remove.png"), QStringLiteral("清空文本"), this);
m_pActQuit = new QAction(QIcon(":/new/back.png"), QStringLiteral("退出"), this);
ui->toolBar->addAction(m_pActBindPort);
ui->toolBar->addAction(m_pActUnbindPort);
ui->toolBar->addSeparator();
ui->toolBar->addAction(m_pActClearText);
ui->toolBar->addSeparator();
ui->toolBar->addAction(m_pActQuit);
//界面布局
m_pCentralWidget = new QWidget(this);
QHBoxLayout* HLay1 = new QHBoxLayout;
m_pLabBindPort = new QLabel(QStringLiteral("绑定端口"), m_pCentralWidget);
m_pSpinBindPort = new QSpinBox(m_pCentralWidget);
m_pSpinBindPort->setMinimum(1);
m_pSpinBindPort->setMaximum(65535);
m_pSpinBindPort->setValue(3200);
m_PLabTargetAddr = new QLabel(QStringLiteral("目标地址"), m_pCentralWidget);
m_pComboTargetAddr = new QComboBox(m_pCentralWidget);
m_pLabTargetPort = new QLabel(QStringLiteral("目标端口"), m_pCentralWidget);
m_pSpinTargetPort = new QSpinBox(m_pCentralWidget);
m_pSpinTargetPort->setMinimum(1);
m_pSpinTargetPort->setMaximum(65535);
m_pSpinTargetPort->setValue(1600);
HLay1->addWidget(m_pLabBindPort, 1, Qt::AlignRight);
HLay1->addWidget(m_pSpinBindPort, 2);
HLay1->addWidget(m_PLabTargetAddr, 1, Qt::AlignRight);
HLay1->addWidget(m_pComboTargetAddr, 4);
HLay1->addWidget(m_pLabTargetPort, 1, Qt::AlignRight);
HLay1->addWidget(m_pSpinTargetPort, 2);
QHBoxLayout* HLay2 = new QHBoxLayout;
m_pLineEdit = new QLineEdit(m_pCentralWidget);
m_pBtnSend = new QPushButton(QStringLiteral("发送消息"), m_pCentralWidget);
m_pBtnBroad = new QPushButton(QStringLiteral("广播消息"), m_pCentralWidget);
HLay2->addWidget(m_pLineEdit);
HLay2->addWidget(m_pBtnSend);
HLay2->addWidget(m_pBtnBroad);
QVBoxLayout* VLay = new QVBoxLayout(m_pCentralWidget); //主布局必须设置parent,否则不会显示布局
// QVBoxLayout* VLay = new QVBoxLayout();
VLay->addLayout(HLay1);
VLay->addLayout(HLay2);
m_pPlainText = new QPlainTextEdit(m_pCentralWidget);
VLay->addWidget(m_pPlainText);
this->setCentralWidget(m_pCentralWidget);
this->setLayout(VLay); //设置为窗体的主布。在指定了主布局的parent之后,这句话可有可无
QString localIP = getLocalIP();
this->setWindowTitle(this->windowTitle() + "---IP:" + localIP);
m_pComboTargetAddr->addItem(localIP);
m_pUdpSocket = new QUdpSocket(this);
//状态栏
m_pLabState = new QLabel(QStringLiteral("socket状态:"), this);
m_pLabState->setMinimumWidth(150);
ui->statusbar->addWidget(m_pLabState);
// connect
connect(m_pActBindPort, &QAction::triggered, this, &MainWindow::slotActBindPort);
connect(m_pActUnbindPort, &QAction::triggered, this, &MainWindow::slotActUnbindPort);
connect(m_pActClearText, &QAction::triggered, this, &MainWindow::slotActClearText);
connect(m_pActQuit, &QAction::triggered, this, &MainWindow::slotActQuit);
connect(m_pBtnSend, &QPushButton::clicked, this, &MainWindow::slotBtnSend);
connect(m_pBtnBroad, &QPushButton::clicked, this, &MainWindow::slotBtnBroad);
connect(m_pUdpSocket, &QUdpSocket::stateChanged, this, &MainWindow::slotSocketStateChanged);
connect(m_pUdpSocket, &QUdpSocket::readyRead, this, &MainWindow::slotSocketReadyRead);
}
MainWindow::~MainWindow() {
//m_pUdpSocket->abort();
//delete m_pUdpSocket;
//m_pUdpSocket = nullptr;
delete ui;
}
void MainWindow::slotActBindPort()
{
quint16 port = m_pSpinBindPort->value(); //本机UDP端口
if (m_pUdpSocket->bind(port)) {
m_pPlainText->appendPlainText(QStringLiteral("**已成功绑定"));
m_pPlainText->appendPlainText(QStringLiteral("绑定端口:") + QString::number(m_pUdpSocket->localPort()));
//使能
m_pActBindPort->setEnabled(false);
m_pActUnbindPort->setEnabled(true);
} else {
m_pPlainText->appendPlainText(QStringLiteral("绑定失败"));
}
}
void MainWindow::slotActUnbindPort() {
m_pUdpSocket->abort(); //解除绑定
m_pPlainText->appendPlainText(QStringLiteral("**已解除绑定"));
m_pActBindPort->setEnabled(true);
m_pActUnbindPort->setEnabled(false);
}
void MainWindow::slotActClearText() { m_pPlainText->clear(); }
void MainWindow::slotActQuit() {
QMessageBox::StandardButton button = QMessageBox::question(this, "", QStringLiteral("是否要退出?"));
if (button == QMessageBox::StandardButton::Yes)
this->close();
}
void MainWindow::slotSocketStateChanged(QAbstractSocket::SocketState socketState) {
switch (socketState)
{
case QAbstractSocket::UnconnectedState: m_pLabState->setText(QStringLiteral("socket状态:UnconnectedState")); break;
case QAbstractSocket::HostLookupState: m_pLabState->setText(QStringLiteral("socket状态:HostLookupState")); break;
case QAbstractSocket::ConnectingState: m_pLabState->setText(QStringLiteral("socket状态:ConnectingState")); break;
case QAbstractSocket::ConnectedState: m_pLabState->setText(QStringLiteral("socket状态:ConnectedState")); break;
case QAbstractSocket::BoundState: m_pLabState->setText(QStringLiteral("socket状态:BoundState")); break;
case QAbstractSocket::ClosingState: m_pLabState->setText(QStringLiteral("socket状态:ClosingState")); break;
default: break;
}
}
void MainWindow::slotBtnSend()
{
QString msg = m_pLineEdit->text();
QByteArray str = msg.toUtf8();
QString targetIp = m_pComboTargetAddr->currentText(); //目标IP
QHostAddress targetAddr(targetIp);
quint16 targetPort = m_pSpinTargetPort->value(); //目标端口
m_pUdpSocket->writeDatagram(str, targetAddr, targetPort);
m_pPlainText->appendPlainText("[out] " + msg);
m_pLineEdit->clear();
m_pLineEdit->setFocus();
}
void MainWindow::slotBtnBroad()
{
QString msg = m_pLineEdit->text();
QByteArray str = msg.toUtf8();
quint16 targetPort = m_pSpinTargetPort->value();
m_pUdpSocket->writeDatagram(str, QHostAddress::Broadcast, targetPort);
m_pPlainText->appendPlainText("[out] " + msg);
m_pLineEdit->clear();
m_pLineEdit->setFocus();
}
void MainWindow::slotSocketReadyRead()
{
while (m_pUdpSocket->hasPendingDatagrams())
{
QByteArray dataGram;
dataGram.resize(m_pUdpSocket->pendingDatagramSize());
QHostAddress peerAddress;
quint16 peerPort;
m_pUdpSocket->readDatagram(dataGram.data(), dataGram.size(), &peerAddress, &peerPort);
QString str = dataGram.data();
QString peer = "[From " + peerAddress.toString() + ":" + QString::number(peerPort) + "]";
m_pPlainText->appendPlainText(peer + str);
}
}
QString MainWindow::getLocalIP() {
QString hostName = QHostInfo::localHostName();
QHostInfo hostInfo = QHostInfo::fromName(hostName);
QString localIP = "";
QList<QHostAddress> addrList = hostInfo.addresses();
if (!addrList.isEmpty()) {
for (int i = 0; i < addrList.size(); i++) {
QHostAddress addr = addrList.at(i);
if (QAbstractSocket::IPv4Protocol == addr.protocol()) {
localIP = addr.toString();
break;
}
}
}
return localIP;
}
结果:
发现自己用UI设计时,发送信息总会出现两个发送信号,并且有一个是空白的,暂时还没有找到问题所在之处,嘤嘤嘤~(/≧▽≦)/
5. UDP组播代码示例
5.1 组播的特性
组播报文的目的地址使用D类IP地址,D类地址不能出现在IP报文的地址字段。用同一个IP多播地址接收多播数据报的所有主机构成一个组,称为多播组(或组播组)。所有的信息接收者都加入一个组内,并且一旦加入后,流向组地址的数据报立即开始向接收者传输,组中的所有的成员都能接收到数据报。组中的成员是动态的,主机可以在任何人时间加入和离开组。
关于组播IP地址,有以下约定:
224.0.0.0 ~ 224.0.0.255 为预留的组播地址(永久组地址),地址224.0.0.0保留不做分配,其他地址供路由协议使用。
224.0.1.0 ~ 224.0.1.255 是公用组播地址,可以用于Internet。
224.0.2.0 ~ 238.255.255.255 为用户可用的组播地址(临时组地址),全网范围内有效。
239.0.0.0 ~ 239.255.255.255 为本地管理组播地址,仅在特定的本地范围内有效。所以,若是在家庭或办公室局域网内测试UDP组播功能,可以使用这些IP。
原文链接:https://blog.csdn.net/WL0616/article/details/129050373
常量定义 |
值 |
描述 |
QUdpSocket::ShareAddress |
0x1 |
1、允许其他服务绑定同样的地址和端口 2、当多进程通过监听同一地址和端口,进而共享单个服务的负载时,将十分有用(例如:一个拥有几个预先建立的监听者的WEB服务器能够改善响应时间)。不过,由于任何服务都允许重新绑定(rebind),该选项应该引起某些安全上的考虑 3、需要注意的是,把该选项和ReuseAddressHint结合,也会允许你的服务重新绑定一个已存在的共享地址 4、在Unix上,该选项等同于SO_REUSEADDR;在Windows上,该选项被忽略 |
QUdpSocket::DontShareAddress |
0x2 |
1、采用专有的方式绑定某个地址和端口,其他任何服务都不能再重新绑定 2、通过该选项,确保绑定成功,指定的服务将是地址和端口唯一监听者,就算是拥有ReuseAddressHint的服务也不允许重新绑定 3、在安全性上,该选项优于ShareAddress,但是在某些操作系统上需要管理员的权限才能运行 4、在Unix和Mac OS上,绑定地址和端口的默认行为是非共享,所以该选项会被忽略;在Windows上,等同于SO_EXCLUSIVEADDRUSE套接字选项 |
QUdpSocket::ReuseAddressHint |
0x4 |
1、为QUdpSocke提供提示,即在地址和端口已经被其他套接字绑定的情况下,也应该试着重新绑定 2、在Unix上,该选项被忽略;在Windows上等同于SO_REUSEADDR 套接字选项 |
QUdpSocket::DefaultForPlatform |
0x0 |
1、当前平台的默认选项 2、在Unix和Mac OS上,该选项等同于DontShareAddress + ReuseAddressHint;在Windows上等同于ShareAddress |
5.2主要程序
.h
#ifndef MAINWINDOW_H
#define MAINWINDOW_H
#include <QAction>
#include <QComboBox>
#include <QHBoxLayout>
#include <QHostInfo>
#include <QLabel>
#include <QLineEdit>
#include <QMainWindow>
#include <QMessageBox>
#include <QPlainTextEdit>
#include <QPushButton>
#include <QRegExp>
#include <QSpinBox>
#include <QUdpSocket>
#include <QVBoxLayout>
namespace Ui {
class MainWindow;
}
class MainWindow : public QMainWindow {
Q_OBJECT
public:
explicit MainWindow(QWidget* parent = 0);
~MainWindow();
private slots:
void slotActJoinMulti();
void slotActLeaveMulti();
void slotActClearText();
void slotActQuit();
void slotSocketStateChanged(QAbstractSocket::SocketState socketState);
void slotBtnMultiMsg();
void slotReadyRead();
private:
Ui::MainWindow* ui;
QAction* m_pActJoinMulti;
QAction* m_pActLeaveMulti;
QAction* m_pActClearText;
QAction* m_pActQuit;
QWidget* m_pCentralWidget;
QLabel* m_pLabPort;
QLabel* m_pLabAddr;
QSpinBox* m_pSpinPort;
QComboBox* m_pComboAddr;
QLineEdit* m_pLineEdit;
QPushButton* m_pBtnSendMulti;
QPlainTextEdit* m_pPlainText;
QLabel* m_pLabState;
QUdpSocket* m_pUdpSocket;
QHostAddress m_multicastAddr;
QString getLocalIP();
};
#endif // MAINWINDOW_H
.cpp
#include "mainwindow.h"
#include "ui_mainwindow.h"
MainWindow::MainWindow(QWidget* parent) : QMainWindow(parent), ui(new Ui::MainWindow) {
ui->setupUi(this);
this->setWindowTitle(QStringLiteral("UDP Multicast"));
//工具栏
ui->mainToolBar->setToolButtonStyle(Qt::ToolButtonTextBesideIcon);
m_pActJoinMulti = new QAction(QIcon(":/new/prefix1/res/添加群组.png"), QStringLiteral("加入组播"), this);
m_pActLeaveMulti = new QAction(QIcon(":/new/prefix1/res/退出群组.png"), QStringLiteral("退出组播"), this);
m_pActClearText = new QAction(QIcon(":/new/prefix1/res/清空.png"), QStringLiteral("清空文本"), this);
m_pActQuit = new QAction(QIcon(":/new/prefix1/res/退出.png"), QStringLiteral("退出"), this);
ui->mainToolBar->addAction(m_pActJoinMulti);
ui->mainToolBar->addAction(m_pActLeaveMulti);
ui->mainToolBar->addSeparator();
ui->mainToolBar->addAction(m_pActClearText);
ui->mainToolBar->addSeparator();
ui->mainToolBar->addAction(m_pActQuit);
//界面布局
m_pCentralWidget = new QWidget(this);
m_pLabPort = new QLabel(QStringLiteral("组播端口"), m_pCentralWidget);
m_pSpinPort = new QSpinBox(m_pCentralWidget);
m_pSpinPort->setMinimum(1);
m_pSpinPort->setMaximum(65535);
m_pSpinPort->setValue(3200);
m_pLabAddr = new QLabel(QStringLiteral("组播地址"), m_pCentralWidget);
m_pComboAddr = new QComboBox(m_pCentralWidget);
m_pComboAddr->setEditable(true); //下拉框可编辑输入
m_pComboAddr->addItem("239.0.0.1");
// 正则匹配 D类IP:224.0.0.0~239.255.255.255
// .必须使用转义字符\,否则.会匹配任意字符
// C++中"\"在字符串中表示要用"\\"
// 是 - 不是 ~ ; 是[0-9]不是[0~9]
QRegExp regExp("^(22[4-9]|23[0-9])(\\.((\\d)|([1-9]\\d)|(1\\d{2})|(2[0-4]\\d)|(25[0-5]))){3}$");
QValidator* pValidator = new QRegExpValidator(regExp, this);
m_pComboAddr->setValidator(pValidator);
QHBoxLayout* HLay1 = new QHBoxLayout();
HLay1->addWidget(m_pLabPort, 1, Qt::AlignRight);
HLay1->addWidget(m_pSpinPort, 1);
HLay1->addWidget(m_pLabAddr, 1, Qt::AlignRight);
HLay1->addWidget(m_pComboAddr, 2);
m_pLineEdit = new QLineEdit(m_pCentralWidget);
m_pBtnSendMulti = new QPushButton(QStringLiteral("组播消息"), m_pCentralWidget);
QHBoxLayout* HLay2 = new QHBoxLayout();
HLay2->addWidget(m_pLineEdit, 4);
HLay2->addWidget(m_pBtnSendMulti, 1);
m_pPlainText = new QPlainTextEdit(m_pCentralWidget);
QVBoxLayout* VLay = new QVBoxLayout(m_pCentralWidget);
VLay->addLayout(HLay1);
VLay->addLayout(HLay2);
VLay->addWidget(m_pPlainText);
this->setCentralWidget(m_pCentralWidget);
this->setLayout(VLay);
//状态栏
m_pLabState = new QLabel(QStringLiteral("socket状态:"), this);
m_pLabState->setMinimumWidth(150);
ui->statusBar->addWidget(m_pLabState);
QString str = getLocalIP();
this->setWindowTitle(this->windowTitle() + "---IP:" + str);
m_pUdpSocket = new QUdpSocket(this);
m_pUdpSocket->setSocketOption(QAbstractSocket::MulticastTtlOption, 1);
// connect
connect(m_pActJoinMulti, &QAction::triggered, this, &MainWindow::slotActJoinMulti);
connect(m_pActLeaveMulti, &QAction::triggered, this, &MainWindow::slotActLeaveMulti);
connect(m_pActClearText, &QAction::triggered, this, &MainWindow::slotActClearText);
connect(m_pActQuit, &QAction::triggered, this, &MainWindow::slotActQuit);
connect(m_pUdpSocket, &QUdpSocket::stateChanged, this, &MainWindow::slotSocketStateChanged);
connect(m_pBtnSendMulti, &QPushButton::clicked, this, &MainWindow::slotBtnMultiMsg);
connect(m_pUdpSocket, &QUdpSocket::readyRead, this, &MainWindow::slotReadyRead);
}
MainWindow::~MainWindow() { delete ui; }
void MainWindow::slotActJoinMulti() {
QString ip = m_pComboAddr->currentText();
m_multicastAddr = QHostAddress(ip);
quint16 multicastPort = m_pSpinPort->value();
if (m_pUdpSocket->bind(QHostAddress::AnyIPv4, multicastPort, QUdpSocket::ShareAddress)) {
m_pUdpSocket->joinMulticastGroup(m_multicastAddr); //加入多播组
m_pPlainText->appendPlainText("**加入组播成功");
m_pPlainText->appendPlainText("**组播地址IP:" + ip);
m_pPlainText->appendPlainText("**绑定端口:" + QString::number(multicastPort));
m_pActJoinMulti->setEnabled(false);
m_pActLeaveMulti->setEnabled(true);
m_pComboAddr->setEditable(false);
} else {
m_pPlainText->appendPlainText("**绑定端口失败");
}
}
void MainWindow::slotActLeaveMulti() {
m_pUdpSocket->leaveMulticastGroup(m_multicastAddr); //退出组播
m_pUdpSocket->abort(); //解除绑定
m_pActJoinMulti->setEnabled(true);
m_pActLeaveMulti->setEnabled(false);
m_pComboAddr->setEnabled(true);
m_pComboAddr->setEditable(true);
m_pPlainText->appendPlainText("**已退出组播,解除端口绑定");
}
void MainWindow::slotActClearText() { m_pPlainText->clear(); }
void MainWindow::slotActQuit() {
QMessageBox::StandardButton button = QMessageBox::question(this, "", "是否退出?");
if (QMessageBox::StandardButton::Yes == button) {
this->close();
}
}
void MainWindow::slotSocketStateChanged(QAbstractSocket::SocketState socketState) {
// case并不包含所有的情况,因为没有写listening的情况,所以就需要写default
switch (socketState) {
case QAbstractSocket::UnconnectedState: m_pLabState->setText("socket状态:UnconnectedState"); break;
case QAbstractSocket::HostLookupState: m_pLabState->setText("socket状态:HostLookupState"); break;
case QAbstractSocket::ConnectingState: m_pLabState->setText("socket状态:ConnectingState"); break;
case QAbstractSocket::ConnectedState: m_pLabState->setText("socket状态:ConnectedState"); break;
case QAbstractSocket::BoundState: m_pLabState->setText("socket状态:BoundState"); break;
case QAbstractSocket::ClosingState: m_pLabState->setText("socket状态:ClosingState"); break;
default: break;
}
}
void MainWindow::slotBtnMultiMsg() {
QString msg = m_pLineEdit->text();
QByteArray str = msg.toUtf8();
quint16 multiPort = m_pSpinPort->value();
m_pUdpSocket->writeDatagram(str, m_multicastAddr, multiPort);
m_pPlainText->appendPlainText("[multicast] " + msg);
m_pLineEdit->clear();
m_pLineEdit->setFocus();
}
void MainWindow::slotReadyRead() {
while (m_pUdpSocket->hasPendingDatagrams()) {
QByteArray dataGram;
dataGram.resize(m_pUdpSocket->pendingDatagramSize());
QHostAddress peerAddr;
quint16 peerPort;
m_pUdpSocket->readDatagram(dataGram.data(), dataGram.size(), &peerAddr, &peerPort);
QString str = dataGram.data();
QString peer = "[From " + peerAddr.toString() + ":" + QString::number(peerPort) + "] ";
m_pPlainText->appendPlainText(peer + str);
qDebug() << m_pUdpSocket->peerAddress();
qDebug() << m_pUdpSocket->localAddress().toString();
qDebug() << m_pUdpSocket->localPort();
}
}
QString MainWindow::getLocalIP() {
QString localName = QHostInfo::localHostName();
QHostInfo hostInfo = QHostInfo::fromName(localName);
QList<QHostAddress> addrList = hostInfo.addresses();
QString localIP = "";
if (!addrList.isEmpty()) {
for (int i = 0; i < addrList.size(); i++) {
QHostAddress addr = addrList.at(i);
if (QAbstractSocket::IPv4Protocol == addr.protocol()) {
localIP = addr.toString();
break;
}
}
}
return localIP;
}
结果:
文章来源:https://www.toymoban.com/news/detail-690583.html
原文链接:https://blog.csdn.net/WL0616/article/details/129050373 文章来源地址https://www.toymoban.com/news/detail-690583.html
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