Qt学习之路_5(Qt TCP的初步使用)
在上一篇博文Qt学习之路_4(Qt UDP的初步使用) 中，初步了解了Qt下UDP的使用，这一节就学习下TCP的使用。2者其实流程都差不多。当然了，本文还是参考的《Qt及Qt Quick开发实战精解》一书中的第5个例子，即局域网聊天工具中的UDP聊天和TCP文件传送部分。另外http://www.yafeilinux.com/ 上有其源码和相关教程下载。
其发送端界面如下：
接收端界面如下：
发送端，也即承担服务器角色的操作：
在主界面程序右侧选择一个需要发送文件的用户，弹出发送端界面后，点击打开按钮，在本地计算机中选择需要发送的文件，点击发送按钮，则进度条上会显示当前文件传送的信息，有已传送文件大小信息，传送速度等信息。如果想关闭发送过程，则单击关闭按钮。
其流程图如下：
接收端，也即承担客户端角色的操作：
当在主界面中突然弹出一个对话框，问是否接自某个用户名和IP地址的文件传送信息，如果接受则单击yes按钮，否则就单击no按钮。当接收文件时，选择好接收文件所存目录和文件名后就开始接收文件了，其过程也会显示已接收文件的大小，接收速度和剩余时间的大小等信息。
其流程图如下：
TCP部分程序代码和注释如下：
Widget.h:
#ifndef WIDGET_H #define WIDGET_H #include <QWidget> class QUdpSocket; class TcpServer;//可以这样定义类？不用保护头文件的？ namespace Ui { class Widget; } // 枚举变量标志信息的类型，分别为消息，新用户加入，用户退出，文件名，拒绝接受文件 enum MessageType{Message, NewParticipant, ParticipantLeft, FileName, Refuse}; class Widget : public QWidget { Q_OBJECT public: explicit Widget(QWidget *parent = 0); ~Widget(); protected: void newParticipant(QString userName, QString localHostName, QString ipAddress); void participantLeft(QString userName, QString localHostName, QString time); void sendMessage(MessageType type, QString serverAddress=""); QString getIP(); QString getUserName(); QString getMessage(); void hasPendingFile(QString userName, QString serverAddress, QString clientAddress, QString fileName); private: Ui::Widget *ui; QUdpSocket *udpSocket; qint16 port; QString fileName; TcpServer *server; private slots: void processPendingDatagrams(); void on_sendButton_clicked(); void getFileName(QString); void on_sendToolBtn_clicked(); }; #endif // WIDGET_H
Widget.cpp:
#include "widget.h" #include "ui_widget.h" #include <QUdpSocket> #include <QHostInfo> #include <QMessageBox> #include <QScrollBar> #include <QDateTime> #include <QNetworkInterface> #include <QProcess> #include "tcpserver.h" #include "tcpclient.h" #include <QFileDialog> Widget::Widget(QWidget *parent) : QWidget(parent), ui(new Ui::Widget) { ui->setupUi(this); udpSocket = new QUdpSocket(this); port = 45454; udpSocket->bind(port, QUdpSocket::ShareAddress | QUdpSocket::ReuseAddressHint); connect(udpSocket, SIGNAL(readyRead()), this, SLOT(processPendingDatagrams())); sendMessage(NewParticipant); //TcpServer是tcpserver.ui对应的类，上面直接用QUdpSocket是因为没有单独的udpserver.ui类 server = new TcpServer(this); //sendFileName()函数一发送，则触发槽函数getFileName() connect(server, SIGNAL(sendFileName(QString)), this, SLOT(getFileName(QString))); } Widget::~Widget() { delete ui; } // 使用UDP广播发送信息 void Widget::sendMessage(MessageType type, QString serverAddress) { QByteArray data; QDataStream out(&data, QIODevice::WriteOnly); QString localHostName = QHostInfo::localHostName(); QString address = getIP(); out << type << getUserName() << localHostName; switch(type) { case Message : if (ui->messageTextEdit->toPlainText() == "") { QMessageBox::warning(0,tr("警告"),tr("发送内容不能为空"),QMessageBox::Ok); return; } out << address << getMessage(); ui->messageBrowser->verticalScrollBar() ->setValue(ui->messageBrowser->verticalScrollBar()->maximum()); break; case NewParticipant : out << address; break; case ParticipantLeft : break; case FileName : { int row = ui->userTableWidget->currentRow();//必须选中需要发送的给谁才可以发送 QString clientAddress = ui->userTableWidget->item(row, 2)->text();//（row,,2）为ip地址 out << address << clientAddress << fileName;//发送本地ip，对方ip，所发送的文件名 break; } case Refuse : out << serverAddress; break; } udpSocket->writeDatagram(data,data.length(),QHostAddress::Broadcast, port); } // 接收UDP信息 void Widget::processPendingDatagrams() { while(udpSocket->hasPendingDatagrams()) { QByteArray datagram; datagram.resize(udpSocket->pendingDatagramSize()); udpSocket->readDatagram(datagram.data(), datagram.size()); QDataStream in(&datagram, QIODevice::ReadOnly); int messageType; in >> messageType; QString userName,localHostName,ipAddress,message; QString time = QDateTime::currentDateTime() .toString("yyyy-MM-dd hh:mm:ss"); switch(messageType) { case Message: in >> userName >> localHostName >> ipAddress >> message; ui->messageBrowser->setTextColor(Qt::blue); ui->messageBrowser->setCurrentFont(QFont("Times New Roman",12)); ui->messageBrowser->append("[ " +userName+" ] "+ time); ui->messageBrowser->append(message); break; case NewParticipant: in >>userName >>localHostName >>ipAddress; newParticipant(userName,localHostName,ipAddress); break; case ParticipantLeft: in >>userName >>localHostName; participantLeft(userName,localHostName,time); break; case FileName: { in >> userName >> localHostName >> ipAddress; QString clientAddress, fileName; in >> clientAddress >> fileName; hasPendingFile(userName, ipAddress, clientAddress, fileName); break; } case Refuse: { in >> userName >> localHostName; QString serverAddress; in >> serverAddress; QString ipAddress = getIP(); if(ipAddress == serverAddress) { server->refused(); } break; } } } } // 处理新用户加入 void Widget::newParticipant(QString userName, QString localHostName, QString ipAddress) { bool isEmpty = ui->userTableWidget->findItems(localHostName, Qt::MatchExactly).isEmpty(); if (isEmpty) { QTableWidgetItem *user = new QTableWidgetItem(userName); QTableWidgetItem *host = new QTableWidgetItem(localHostName); QTableWidgetItem *ip = new QTableWidgetItem(ipAddress); ui->userTableWidget->insertRow(0); ui->userTableWidget->setItem(0,0,user); ui->userTableWidget->setItem(0,1,host); ui->userTableWidget->setItem(0,2,ip); ui->messageBrowser->setTextColor(Qt::gray); ui->messageBrowser->setCurrentFont(QFont("Times New Roman",10)); ui->messageBrowser->append(tr("%1 在线！").arg(userName)); ui->userNumLabel->setText(tr("在线人数：%1").arg(ui->userTableWidget->rowCount())); sendMessage(NewParticipant); } } // 处理用户离开 void Widget::participantLeft(QString userName, QString localHostName, QString time) { int rowNum = ui->userTableWidget->findItems(localHostName, Qt::MatchExactly).first()->row(); ui->userTableWidget->removeRow(rowNum); ui->messageBrowser->setTextColor(Qt::gray); ui->messageBrowser->setCurrentFont(QFont("Times New Roman", 10)); ui->messageBrowser->append(tr("%1 于 %2 离开！").arg(userName).arg(time)); ui->userNumLabel->setText(tr("在线人数：%1").arg(ui->userTableWidget->rowCount())); } // 获取ip地址 QString Widget::getIP() { QList<QHostAddress> list = QNetworkInterface::allAddresses(); foreach (QHostAddress address, list) { if(address.protocol() == QAbstractSocket::IPv4Protocol) return address.toString(); } return 0; } // 获取用户名 QString Widget::getUserName() { QStringList envVariables; envVariables << "USERNAME.*" << "USER.*" << "USERDOMAIN.*" << "HOSTNAME.*" << "DOMAINNAME.*"; QStringList environment = QProcess::systemEnvironment(); foreach (QString string, envVariables) { int index = environment.indexOf(QRegExp(string)); if (index != -1) { QStringList stringList = environment.at(index).split('='); if (stringList.size() == 2) { return stringList.at(1); break; } } } return "unknown"; } // 获得要发送的消息 QString Widget::getMessage() { QString msg = ui->messageTextEdit->toHtml(); ui->messageTextEdit->clear(); ui->messageTextEdit->setFocus(); return msg; } // 发送消息 void Widget::on_sendButton_clicked() { sendMessage(Message); } // 获取要发送的文件名 void Widget::getFileName(QString name) { fileName = name; sendMessage(FileName); } // 传输文件按钮 void Widget::on_sendToolBtn_clicked() { if(ui->userTableWidget->selectedItems().isEmpty())//传送文件前需选择用户 { QMessageBox::warning(0, tr("选择用户"), tr("请先从用户列表选择要传送的用户！"), QMessageBox::Ok); return; } server->show(); server->initServer(); } // 是否接收文件，客户端的显示 void Widget::hasPendingFile(QString userName, QString serverAddress, QString clientAddress, QString fileName) { QString ipAddress = getIP(); if(ipAddress == clientAddress) { int btn = QMessageBox::information(this,tr("接受文件"), tr("来自%1(%2)的文件：%3,是否接收？") .arg(userName).arg(serverAddress).arg(fileName), QMessageBox::Yes,QMessageBox::No);//弹出一个窗口 if (btn == QMessageBox::Yes) { QString name = QFileDialog::getSaveFileName(0,tr("保存文件"),fileName);//name为另存为的文件名 if(!name.isEmpty()) { TcpClient *client = new TcpClient(this); client->setFileName(name); //客户端设置文件名 client->setHostAddress(QHostAddress(serverAddress)); //客户端设置服务器地址 client->show(); } } else { sendMessage(Refuse, serverAddress); } } }
Tcpserver.h:
#ifndef TCPSERVER_H #define TCPSERVER_H #include <QDialog> #include <QTime> class QFile; class QTcpServer; class QTcpSocket; namespace Ui { class TcpServer; } class TcpServer : public QDialog { Q_OBJECT public: explicit TcpServer(QWidget *parent = 0); ~TcpServer(); void initServer(); void refused(); protected: void closeEvent(QCloseEvent *); private: Ui::TcpServer *ui; qint16 tcpPort; QTcpServer *tcpServer; QString fileName; QString theFileName; QFile *localFile; qint64 TotalBytes; qint64 bytesWritten; qint64 bytesToWrite; qint64 payloadSize; QByteArray outBlock; QTcpSocket *clientConnection; QTime time; private slots: void sendMessage(); void updateClientProgress(qint64 numBytes); void on_serverOpenBtn_clicked(); void on_serverSendBtn_clicked(); void on_serverCloseBtn_clicked(); signals: void sendFileName(QString fileName); }; #endif // TCPSERVER_H
Tcpserver.cpp:
#include "tcpserver.h" #include "ui_tcpserver.h" #include <QFile> #include <QTcpServer> #include <QTcpSocket> #include <QMessageBox> #include <QFileDialog> #include <QDebug> TcpServer::TcpServer(QWidget *parent) : QDialog(parent), ui(new Ui::TcpServer) { ui->setupUi(this); //每一个新类都有一个自己的ui setFixedSize(350,180); //初始化时窗口显示固定大小 tcpPort = 6666; //tcp通信端口 tcpServer = new QTcpServer(this); //newConnection表示当tcp有新连接时就发送信号 connect(tcpServer, SIGNAL(newConnection()), this, SLOT(sendMessage())); initServer(); } TcpServer::~TcpServer() { delete ui; } // 初始化 void TcpServer::initServer() { payloadSize = 64*1024; TotalBytes = 0; bytesWritten = 0; bytesToWrite = 0; ui->serverStatusLabel->setText(tr("请选择要传送的文件")); ui->progressBar->reset();//进度条复位 ui->serverOpenBtn->setEnabled(true);//open按钮可用 ui->serverSendBtn->setEnabled(false);//发送按钮不可用 tcpServer->close();//tcp传送文件窗口不显示 } // 开始发送数据 void TcpServer::sendMessage() //是connect中的槽函数 { ui->serverSendBtn->setEnabled(false); //当在传送文件的过程中，发送按钮不可用 clientConnection = tcpServer->nextPendingConnection(); //用来获取一个已连接的TcpSocket //bytesWritten为qint64类型，即长整型 connect(clientConnection, SIGNAL(bytesWritten(qint64)), //? this, SLOT(updateClientProgress(qint64))); ui->serverStatusLabel->setText(tr("开始传送文件 %1 ！").arg(theFileName)); localFile = new QFile(fileName); //localFile代表的是文件内容本身 if(!localFile->open((QFile::ReadOnly))){ QMessageBox::warning(this, tr("应用程序"), tr("无法读取文件 %1:\n%2") .arg(fileName).arg(localFile->errorString()));//errorString是系统自带的信息 return; } TotalBytes = localFile->size();//文件总大小 //头文件中的定义QByteArray outBlock; QDataStream sendOut(&outBlock, QIODevice::WriteOnly);//设置输出流属性 sendOut.setVersion(QDataStream::Qt_4_7);//设置Qt版本，不同版本的数据流格式不同 time.start(); // 开始计时 QString currentFile = fileName.right(fileName.size() //currentFile代表所选文件的文件名 - fileName.lastIndexOf('/')-1); //qint64(0)表示将0转换成qint64类型,与(qint64)0等价 //如果是，则此处为依次写入总大小信息空间，文件名大小信息空间，文件名 sendOut << qint64(0) << qint64(0) << currentFile; TotalBytes += outBlock.size();//文件名大小等信息+实际文件大小 //sendOut.device()为返回io设备的当前设置，seek(0)表示设置当前pos为0 sendOut.device()->seek(0);//返回到outBlock的开始，执行覆盖操作 //发送总大小空间和文件名大小空间 sendOut << TotalBytes << qint64((outBlock.size() - sizeof(qint64)*2)); //qint64 bytesWritten;bytesToWrite表示还剩下的没发送完的数据 //clientConnection->write(outBlock)为套接字将内容发送出去，返回实际发送出去的字节数 bytesToWrite = TotalBytes - clientConnection->write(outBlock); outBlock.resize(0);//why?? } // 更新进度条，有数据发送时触发 void TcpServer::updateClientProgress(qint64 numBytes) { //qApp为指向一个应用对象的全局指针 qApp->processEvents();//processEvents为处理所有的事件？ bytesWritten += (int)numBytes; if (bytesToWrite > 0) { //没发送完毕 //初始化时payloadSize = 64*1024;qMin为返回参数中较小的值，每次最多发送64K的大小 outBlock = localFile->read(qMin(bytesToWrite, payloadSize)); bytesToWrite -= (int)clientConnection->write(outBlock); outBlock.resize(0);//清空发送缓冲区 } else { localFile->close(); } ui->progressBar->setMaximum(TotalBytes);//进度条的最大值为所发送信息的所有长度(包括附加信息) ui->progressBar->setValue(bytesWritten);//进度条显示的进度长度为bytesWritten实时的长度 float useTime = time.elapsed();//从time.start()还是到当前所用的时间记录在useTime中 double speed = bytesWritten / useTime; ui->serverStatusLabel->setText(tr("已发送 %1MB (%2MB/s) " "\n共%3MB 已用时:%4秒\n估计剩余时间：%5秒") .arg(bytesWritten / (1024*1024)) //转化成MB .arg(speed*1000 / (1024*1024), 0, 'f', 2) .arg(TotalBytes / (1024 * 1024)) .arg(useTime/1000, 0, 'f', 0) //0，‘f’,0是什么意思啊？ .arg(TotalBytes/speed/1000 - useTime/1000, 0, 'f', 0)); if(bytesWritten == TotalBytes) { //当需发送文件的总长度等于已发送长度时，表示发送完毕！ localFile->close(); tcpServer->close(); ui->serverStatusLabel->setText(tr("传送文件 %1 成功").arg(theFileName)); } } // 打开按钮 void TcpServer::on_serverOpenBtn_clicked() { //QString fileName;QFileDialog是一个提供给用户选择文件或目录的对话框 fileName = QFileDialog::getOpenFileName(this); //filename为所选择的文件名(包含了路径名) if(!fileName.isEmpty()) { //fileName.right为返回filename最右边参数大小个字文件名，theFileName为所选真正的文件名 theFileName = fileName.right(fileName.size() - fileName.lastIndexOf('/')-1); ui->serverStatusLabel->setText(tr("要传送的文件为：%1 ").arg(theFileName)); ui->serverSendBtn->setEnabled(true);//发送按钮可用 ui->serverOpenBtn->setEnabled(false);//open按钮禁用 } } // 发送按钮 void TcpServer::on_serverSendBtn_clicked() { //tcpServer->listen函数如果监听到有连接，则返回1，否则返回0 if(!tcpServer->listen(QHostAddress::Any,tcpPort))//开始监听6666端口 { qDebug() << tcpServer->errorString();//此处的errorString是指？ close(); return; } ui->serverStatusLabel->setText(tr("等待对方接收... ...")); emit sendFileName(theFileName);//发送已传送文件的信号，在widget.cpp构造函数中的connect()触发槽函数 } // 关闭按钮，服务器端的关闭按钮 void TcpServer::on_serverCloseBtn_clicked() { if(tcpServer->isListening()) { //当tcp正在监听时，关闭tcp服务器端应用，即按下close键时就不监听tcp请求了 tcpServer->close(); if (localFile->isOpen())//如果所选择的文件已经打开，则关闭掉 localFile->close(); clientConnection->abort();//clientConnection为下一个连接？怎么理解 } close();//关闭本ui，即本对话框 } // 被对方拒绝 void TcpServer::refused() { tcpServer->close(); ui->serverStatusLabel->setText(tr("对方拒绝接收！！！")); } // 关闭事件 void TcpServer::closeEvent(QCloseEvent *) { on_serverCloseBtn_clicked(); }
Tcpclient.h:
#ifndef TCPCLIENT_H #define TCPCLIENT_H #include <QDialog> #include <QHostAddress> #include <QFile> #include <QTime> class QTcpSocket; namespace Ui { class TcpClient; } class TcpClient : public QDialog { Q_OBJECT public: explicit TcpClient(QWidget *parent = 0); ~TcpClient(); void setHostAddress(QHostAddress address); void setFileName(QString fileName); protected: void closeEvent(QCloseEvent *); private: Ui::TcpClient *ui; QTcpSocket *tcpClient; quint16 blockSize; QHostAddress hostAddress; qint16 tcpPort; qint64 TotalBytes; qint64 bytesReceived; qint64 bytesToReceive; qint64 fileNameSize; QString fileName; QFile *localFile; QByteArray inBlock; QTime time; private slots: void on_tcpClientCancleBtn_clicked(); void on_tcpClientCloseBtn_clicked(); void newConnect(); void readMessage(); void displayError(QAbstractSocket::SocketError); }; #endif // TCPCLIENT_H
Tcpclient.cpp:
#include "tcpclient.h" #include "ui_tcpclient.h" #include <QTcpSocket> #include <QDebug> #include <QMessageBox> TcpClient::TcpClient(QWidget *parent) : QDialog(parent), ui(new Ui::TcpClient) { ui->setupUi(this); setFixedSize(350,180); TotalBytes = 0; bytesReceived = 0; fileNameSize = 0; tcpClient = new QTcpSocket(this); tcpPort = 6666; connect(tcpClient, SIGNAL(readyRead()), this, SLOT(readMessage())); connect(tcpClient, SIGNAL(error(QAbstractSocket::SocketError)), this, SLOT(displayError(QAbstractSocket::SocketError))); } TcpClient::~TcpClient() { delete ui; } // 设置文件名 void TcpClient::setFileName(QString fileName) { localFile = new QFile(fileName); } // 设置地址 void TcpClient::setHostAddress(QHostAddress address) { hostAddress = address; newConnect(); } // 创建新连接 void TcpClient::newConnect() { blockSize = 0; tcpClient->abort(); //取消已有的连接 tcpClient->connectToHost(hostAddress, tcpPort);//连接到指定ip地址和端口的主机 time.start(); } // 读取数据 void TcpClient::readMessage() { QDataStream in(tcpClient); //这里的QDataStream可以直接用QTcpSocket对象做参数 in.setVersion(QDataStream::Qt_4_7); float useTime = time.elapsed(); if (bytesReceived <= sizeof(qint64)*2) { //说明刚开始接受数据 if ((tcpClient->bytesAvailable() //bytesAvailable为返回将要被读取的字节数 >= sizeof(qint64)*2) && (fileNameSize == 0)) { //接受数据总大小信息和文件名大小信息 in>>TotalBytes>>fileNameSize; bytesReceived += sizeof(qint64)*2; } if((tcpClient->bytesAvailable() >= fileNameSize) && (fileNameSize != 0)){ //开始接受文件，并建立文件 in>>fileName; bytesReceived +=fileNameSize; if(!localFile->open(QFile::WriteOnly)){ QMessageBox::warning(this,tr("应用程序"),tr("无法读取文件 %1:\n%2.") .arg(fileName).arg(localFile->errorString())); return; } } else { return; } } if (bytesReceived < TotalBytes) { bytesReceived += tcpClient->bytesAvailable();//返回tcpClient中字节的总数 inBlock = tcpClient->readAll(); //返回读到的所有数据 localFile->write(inBlock); inBlock.resize(0); } ui->progressBar->setMaximum(TotalBytes); ui->progressBar->setValue(bytesReceived); double speed = bytesReceived / useTime; ui->tcpClientStatusLabel->setText(tr("已接收 %1MB (%2MB/s) " "\n共%3MB 已用时:%4秒\n估计剩余时间：%5秒") .arg(bytesReceived / (1024*1024)) .arg(speed*1000/(1024*1024),0,'f',2) .arg(TotalBytes / (1024 * 1024)) .arg(useTime/1000,0,'f',0) .arg(TotalBytes/speed/1000 - useTime/1000,0,'f',0)); if(bytesReceived == TotalBytes) { localFile->close(); tcpClient->close(); ui->tcpClientStatusLabel->setText(tr("接收文件 %1 完毕") .arg(fileName)); } } // 错误处理 //QAbstractSocket类提供了所有scoket的通用功能，socketError为枚举型 void TcpClient::displayError(QAbstractSocket::SocketError socketError) { switch(socketError) { //RemoteHostClosedError为远处主机关闭了连接时发出的错误信号 case QAbstractSocket::RemoteHostClosedError : break; default : qDebug() << tcpClient->errorString(); } } // 取消按钮 void TcpClient::on_tcpClientCancleBtn_clicked() { tcpClient->abort(); if (localFile->isOpen()) localFile->close(); } // 关闭按钮 void TcpClient::on_tcpClientCloseBtn_clicked() { tcpClient->abort(); if (localFile->isOpen()) localFile->close(); close(); } // 关闭事件 void TcpClient::closeEvent(QCloseEvent *) { on_tcpClientCloseBtn_clicked(); }
Main.cpp:
#include <QtGui/QApplication> #include "widget.h" #include <QTextCodec> int main(int argc, char *argv[]) { QApplication a(argc, argv); QTextCodec::setCodecForTr(QTextCodec::codecForLocale()); Widget w; w.show(); return a.exec(); }
作者：tornadomeet
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