udp通信

UDP（User Data Protocol）用户数据报协议，是一种不可靠，面向数据报的无连接的传输层协议。

   UDP客户端向UDP服务器发送一定长度的请求报文，UDP服务器同样以报文的形式作出响应，如果服务器为收到此请求，客户端不会进行重发，故此报文的传输是不可靠的；

       发送需要知道：对方IP地址，端口号

       接收方：端口号

主要是针对局域网内一对一的传输，两台PC可以进行通信；

操作界面如下： 其中远程端IP和端口号可更改；

                   本端发送消息，本端接收端会显示发送的内容，同时发送的内容会被清空；

下图显示的内容是 本端先发送内容“你好”给远程端，远程端操作进行回复，图片显示的结果说明两端通信正常；

#ifndef SERVER_H
#define SERVER_H
#include<QApplication>
#include <QWidget>
#include<QLabel>
#include<QLineEdit>
#include<QTextEdit>
#include<QPushButton>
#include<QGridLayout>
#include<QHBoxLayout>

#include<QMessageBox>
#include<QtNetwork/QUdpSocket>
#include<QtNetwork/QHostAddress>
#include<QtNetwork/QNetworkInterface>
#include<QtNetwork/QHostInfo>

#include<QTime>

class server : public QWidget
{
    Q_OBJECT

public:
    server(QWidget *parent = 0);
    ~server();
    QHostAddress  localHostAddr;
    QHostAddress   remoteHostAddr;

    QTime     time;
    QString  timeStr;
    QUdpSocket *sendSocket;
    QUdpSocket *receiveSocket;

    int port;
    void autoScroll(QTextEdit& Edit);
    QString getIP();
    QString localIP;


private slots:
    void send();
    void receive();

    void InitState();
    void close();


private:
    QLabel      *RemoteIpLabel;
    QLineEdit   *RemoteIpLineEdit;
    QLabel      *MyselfIpLabel;
    QLineEdit   *MyselfIpLineEdit;
    QLabel      *PortLabel;
    QLineEdit   *PortLineEdit;
    QTextEdit   *RecvTextEdit;
    QTextEdit   *SendTextEdit;
    QLabel      *SendLabel;
    QLabel      *RecvLabel;

    QPushButton *ClearBtn;
    QPushButton *ExitBtn;
    QPushButton *SendBtn;

    QGridLayout *mainLayout;
    QGridLayout *TopLayout;
    QVBoxLayout *SendLayout;
    QVBoxLayout *RecvLayout;


};

#endif // SERVER_H

#include "server.h"
#include<QCoreApplication>
#include<QList>
#include<QByteArray>
#include<QtNetwork/QHostAddress>
#include<QtNetwork/QUdpSocket>
#include<QtNetwork/QAbstractSocket>
#include<QtNetwork/QNetworkInterface>
#include<QtNetwork/QHostInfo>
#include<QMessageBox>

#include<QByteArray>
#include<QTextCursor>
server::server(QWidget *parent)
    : QWidget(parent)
{

    RemoteIpLabel=new QLabel(tr("远程端IP:"));
    RemoteIpLineEdit=new QLineEdit("192.168.40.101");
    MyselfIpLabel=new QLabel("本端IP");
    MyselfIpLineEdit=new QLineEdit;
    MyselfIpLineEdit->setText(getIP());
    MyselfIpLineEdit->setEnabled(false);

    PortLabel=new QLabel(tr("端口号："));
    PortLineEdit=new QLineEdit("5555");

    RecvLabel=new QLabel(tr("信息交互"));
    RecvTextEdit=new QTextEdit;

    SendLabel=new QLabel(tr("发送信息"));
    SendTextEdit=new QTextEdit;


    ClearBtn=new QPushButton(tr("clear"));
    ExitBtn=new QPushButton(tr("exit"));
    SendBtn=new QPushButton(tr("发送"));

    TopLayout=new QGridLayout;
    TopLayout->addWidget(MyselfIpLabel,0,0);
    TopLayout->addWidget(MyselfIpLineEdit,0,1);
    TopLayout->addWidget(RemoteIpLabel,1,0);
    TopLayout->addWidget(RemoteIpLineEdit,1,1);
    TopLayout->addWidget(PortLabel,1,2);
    TopLayout->addWidget(PortLineEdit,1,3);



    SendLayout=new QVBoxLayout;
    SendLayout->addWidget(SendLabel);
    SendLayout->addWidget(SendTextEdit);


    RecvLayout=new QVBoxLayout;
    RecvLayout->addWidget(RecvLabel);
    RecvLayout->addWidget(RecvTextEdit);

    mainLayout=new QGridLayout(this);
    mainLayout->addLayout(TopLayout,0,0);
    mainLayout->addLayout(RecvLayout,1,0);
    mainLayout->addLayout(SendLayout,2,0);
    mainLayout->addWidget(SendBtn,3,1,2,2);
    mainLayout->addWidget(ExitBtn,3,3,2,2);

//     int port=0;

    sendSocket=new QUdpSocket(this);
    QTime time=QTime::currentTime();
    timeStr=time.toString("hh:mm:ss");

    InitState();
    connect(SendBtn,SIGNAL(clicked()),this,SLOT(send()));
    connect(ExitBtn,SIGNAL(clicked()),this,SLOT(close()));

}

server::~server()
{

}

void server::send()
{
    sendSocket->open(QIODevice::Append);
    qDebug()<<"发送信息";
    bool ok;

    autoScroll(*RecvTextEdit);//滚屏

    localIP=getIP();//获取本地IP地址

    remoteHostAddr=QHostAddress(RemoteIpLineEdit->text());
    port=PortLineEdit->text().toInt(&ok);
    sendSocket->bind(QHostAddress::AnyIPv4,port);

    QByteArray datagram =localIP.toUtf8()+"  	"+"
"+SendTextEdit->toPlainText().toUtf8();
    if(SendTextEdit->toPlainText().toUtf8()!="")
    {
     qDebug()<<sendSocket->writeDatagram(datagram.data(),datagram.size(),QHostAddress(remoteHostAddr),5555);
     RecvTextEdit->append(datagram+"	");
     SendTextEdit->clear();
    }
    else
    {
        qDebug()<<"输入为空";
        QMessageBox::about(this,"消息提示框","发送内容不能为空!");

    }
}
void server::receive()
{
    while(sendSocket->hasPendingDatagrams())
    {
        QByteArray datagram;
        datagram.resize(sendSocket->pendingDatagramSize());
       // QDateTime timerecv=QDateTime::currentDateTime();
        //QString  recvtimeStr=timerecv.toString("yyyy-MM-dd hh:mm:ss");
        QHostAddress sender;
        quint16 sendPort;

        autoScroll(*RecvTextEdit); //自动滚屏
        sendSocket->readDatagram(datagram.data(),datagram.size(),&sender,&sendPort);
        if(datagram!=NULL)
        {
         RecvTextEdit->append(datagram+"	");
        }

    }

}
void server::InitState()
{

    sendSocket->open(QIODevice::Append);
    SendTextEdit->clear();
    qDebug()<<"接收信息";
    sendSocket->bind(5555);
    connect(sendSocket,SIGNAL(readyRead()),this,SLOT(receive()));

}

void server::autoScroll(QTextEdit& Edit)
{
      QTextCursor cursor= Edit.textCursor();
      cursor.movePosition(QTextCursor::End);
      Edit.setTextCursor(cursor);
}

QString server::getIP()
{
    QString ip;
    QHostInfo info =QHostInfo::fromName(QHostInfo::localHostName());
    info.addresses();
    foreach(QHostAddress address,info.addresses())
    {
        if(address.protocol()==QAbstractSocket::IPv4Protocol)
        {
            qDebug()<<address.toString();
            ip=address.toString();
        }
    }

    return ip;
}
void server ::close()
{

  QApplication *serverApp;
   serverApp->quit();


}