Qt學習之路_5(Qt TCP的初步使用)
在上一篇博文Qt學習之路_4(Qt UDP的初步使用) 中,初步瞭解了Qt下UDP的使用,這一節就學習下TCP的使用。2者其實流程都差不多。當然了,本文還是參考的《Qt及Qt Quick開發實戰精解》一書中的第5個例子,即局域網聊天工具中的UDP聊天和TCP文件傳送部分。另外http://www.yafeilinux.com/ 上有其源碼和相關教程下載。
其發送端界面如下:
接收端界面如下:
發送端,也即承擔服務器角色的操作:
在主界面程序右側選擇一個需要發送文件的用戶,彈出發送端界面後,點擊打開按鈕,在本地計算機中選擇需要發送的文件,點擊發送按鈕,則進度條上會顯示當前文件傳送的信息,有已傳送文件大小信息,傳送速度等信息。如果想關閉發送過程,則單擊關閉按鈕。
其流程圖如下:
接收端,也即承擔客戶端角色的操作:
當在主界面中突然彈出一個對話框,問是否接自某個用戶名和IP地址的文件傳送信息,如果接受則單擊yes按鈕,否則就單擊no按鈕。當接收文件時,選擇好接收文件所存目錄和文件名後就開始接收文件了,其過程也會顯示已接收文件的大小,接收速度和剩餘時間的大小等信息。
其流程圖如下:
TCP部分程序代碼和註釋如下:
Widget.h:
#ifndef WIDGET_H
#define WIDGET_H
#include <QWidget>
class QUdpSocket;
class TcpServer;//可以這樣定義類?不用保護頭文件的?
namespace Ui {
class Widget;
}
// 枚舉變量標誌信息的類型,分別爲消息,新用戶加入,用戶退出,文件名,拒絕接受文件
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對應的類,上面直接用QUdpSocket是因爲沒有單獨的udpserver.ui類
server = new TcpServer(this);
//sendFileName()函數一發送,則觸發槽函數getFileName()
connect(server, SIGNAL(sendFileName(QString)), this, SLOT(getFileName(QString)));
}
Widget::~Widget()
{
delete ui;
}
// 使用UDP廣播發送信息
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("發送內容不能爲空"),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();//必須選中需要發送的給誰纔可以發送
QString clientAddress = ui->userTableWidget->item(row, 2)->text();//(row,,2)爲ip地址
out << address << clientAddress << fileName;//發送本地ip,對方ip,所發送的文件名
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;
}
}
}
}
// 處理新用戶加入
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 在線!").arg(userName));
ui->userNumLabel->setText(tr("在線人數:%1").arg(ui->userTableWidget->rowCount()));
sendMessage(NewParticipant);
}
}
// 處理用戶離開
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 於 %2 離開!").arg(userName).arg(time));
ui->userNumLabel->setText(tr("在線人數:%1").arg(ui->userTableWidget->rowCount()));
}
// 獲取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;
}
// 獲取用戶名
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";
}
// 獲得要發送的消息
QString Widget::getMessage()
{
QString msg = ui->messageTextEdit->toHtml();
ui->messageTextEdit->clear();
ui->messageTextEdit->setFocus();
return msg;
}
// 發送消息
void Widget::on_sendButton_clicked()
{
sendMessage(Message);
}
// 獲取要發送的文件名
void Widget::getFileName(QString name)
{
fileName = name;
sendMessage(FileName);
}
// 傳輸文件按鈕
void Widget::on_sendToolBtn_clicked()
{
if(ui->userTableWidget->selectedItems().isEmpty())//傳送文件前需選擇用戶
{
QMessageBox::warning(0, tr("選擇用戶"),
tr("請先從用戶列表選擇要傳送的用戶!"), QMessageBox::Ok);
return;
}
server->show();
server->initServer();
}
// 是否接收文件,客戶端的顯示
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("來自%1(%2)的文件:%3,是否接收?")
.arg(userName).arg(serverAddress).arg(fileName),
QMessageBox::Yes,QMessageBox::No);//彈出一個窗口
if (btn == QMessageBox::Yes) {
QString name = QFileDialog::getSaveFileName(0,tr("保存文件"),fileName);//name爲另存爲的文件名
if(!name.isEmpty())
{
TcpClient *client = new TcpClient(this);
client->setFileName(name); //客戶端設置文件名
client->setHostAddress(QHostAddress(serverAddress)); //客戶端設置服務器地址
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); //每一個新類都有一個自己的ui
setFixedSize(350,180); //初始化時窗口顯示固定大小
tcpPort = 6666; //tcp通信端口
tcpServer = new QTcpServer(this);
//newConnection表示當tcp有新連接時就發送信號
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("請選擇要傳送的文件"));
ui->progressBar->reset();//進度條復位
ui->serverOpenBtn->setEnabled(true);//open按鈕可用
ui->serverSendBtn->setEnabled(false);//發送按鈕不可用
tcpServer->close();//tcp傳送文件窗口不顯示
}
// 開始發送數據
void TcpServer::sendMessage() //是connect中的槽函數
{
ui->serverSendBtn->setEnabled(false); //當在傳送文件的過程中,發送按鈕不可用
clientConnection = tcpServer->nextPendingConnection(); //用來獲取一個已連接的TcpSocket
//bytesWritten爲qint64類型,即長整型
connect(clientConnection, SIGNAL(bytesWritten(qint64)), //?
this, SLOT(updateClientProgress(qint64)));
ui->serverStatusLabel->setText(tr("開始傳送文件 %1 !").arg(theFileName));
localFile = new QFile(fileName); //localFile代表的是文件內容本身
if(!localFile->open((QFile::ReadOnly))){
QMessageBox::warning(this, tr("應用程序"), tr("無法讀取文件 %1:\n%2")
.arg(fileName).arg(localFile->errorString()));//errorString是系統自帶的信息
return;
}
TotalBytes = localFile->size();//文件總大小
//頭文件中的定義QByteArray outBlock;
QDataStream sendOut(&outBlock, QIODevice::WriteOnly);//設置輸出流屬性
sendOut.setVersion(QDataStream::Qt_4_7);//設置Qt版本,不同版本的數據流格式不同
time.start(); // 開始計時
QString currentFile = fileName.right(fileName.size() //currentFile代表所選文件的文件名
- fileName.lastIndexOf('/')-1);
//qint64(0)表示將0轉換成qint64類型,與(qint64)0等價
//如果是,則此處爲依次寫入總大小信息空間,文件名大小信息空間,文件名
sendOut << qint64(0) << qint64(0) << currentFile;
TotalBytes += outBlock.size();//文件名大小等信息+實際文件大小
//sendOut.device()爲返回io設備的當前設置,seek(0)表示設置當前pos爲0
sendOut.device()->seek(0);//返回到outBlock的開始,執行覆蓋操作
//發送總大小空間和文件名大小空間
sendOut << TotalBytes << qint64((outBlock.size() - sizeof(qint64)*2));
//qint64 bytesWritten;bytesToWrite表示還剩下的沒發送完的數據
//clientConnection->write(outBlock)爲套接字將內容發送出去,返回實際發送出去的字節數
bytesToWrite = TotalBytes - clientConnection->write(outBlock);
outBlock.resize(0);//why??
}
// 更新進度條,有數據發送時觸發
void TcpServer::updateClientProgress(qint64 numBytes)
{
//qApp爲指向一個應用對象的全局指針
qApp->processEvents();//processEvents爲處理所有的事件?
bytesWritten += (int)numBytes;
if (bytesToWrite > 0) { //沒發送完畢
//初始化時payloadSize = 64*1024;qMin爲返回參數中較小的值,每次最多發送64K的大小
outBlock = localFile->read(qMin(bytesToWrite, payloadSize));
bytesToWrite -= (int)clientConnection->write(outBlock);
outBlock.resize(0);//清空發送緩衝區
} else {
localFile->close();
}
ui->progressBar->setMaximum(TotalBytes);//進度條的最大值爲所發送信息的所有長度(包括附加信息)
ui->progressBar->setValue(bytesWritten);//進度條顯示的進度長度爲bytesWritten實時的長度
float useTime = time.elapsed();//從time.start()還是到當前所用的時間記錄在useTime中
double speed = bytesWritten / useTime;
ui->serverStatusLabel->setText(tr("已發送 %1MB (%2MB/s) "
"\n共%3MB 已用時:%4秒\n估計剩餘時間:%5秒")
.arg(bytesWritten / (1024*1024)) //轉化成MB
.arg(speed*1000 / (1024*1024), 0, 'f', 2)
.arg(TotalBytes / (1024 * 1024))
.arg(useTime/1000, 0, 'f', 0) //0,‘f’,0是什麼意思啊?
.arg(TotalBytes/speed/1000 - useTime/1000, 0, 'f', 0));
if(bytesWritten == TotalBytes) { //當需發送文件的總長度等於已發送長度時,表示發送完畢!
localFile->close();
tcpServer->close();
ui->serverStatusLabel->setText(tr("傳送文件 %1 成功").arg(theFileName));
}
}
// 打開按鈕
void TcpServer::on_serverOpenBtn_clicked()
{
//QString fileName;QFileDialog是一個提供給用戶選擇文件或目錄的對話框
fileName = QFileDialog::getOpenFileName(this); //filename爲所選擇的文件名(包含了路徑名)
if(!fileName.isEmpty())
{
//fileName.right爲返回filename最右邊參數大小個字文件名,theFileName爲所選真正的文件名
theFileName = fileName.right(fileName.size() - fileName.lastIndexOf('/')-1);
ui->serverStatusLabel->setText(tr("要傳送的文件爲:%1 ").arg(theFileName));
ui->serverSendBtn->setEnabled(true);//發送按鈕可用
ui->serverOpenBtn->setEnabled(false);//open按鈕禁用
}
}
// 發送按鈕
void TcpServer::on_serverSendBtn_clicked()
{
//tcpServer->listen函數如果監聽到有連接,則返回1,否則返回0
if(!tcpServer->listen(QHostAddress::Any,tcpPort))//開始監聽6666端口
{
qDebug() << tcpServer->errorString();//此處的errorString是指?
close();
return;
}
ui->serverStatusLabel->setText(tr("等待對方接收... ..."));
emit sendFileName(theFileName);//發送已傳送文件的信號,在widget.cpp構造函數中的connect()觸發槽函數
}
// 關閉按鈕,服務器端的關閉按鈕
void TcpServer::on_serverCloseBtn_clicked()
{
if(tcpServer->isListening())
{
//當tcp正在監聽時,關閉tcp服務器端應用,即按下close鍵時就不監聽tcp請求了
tcpServer->close();
if (localFile->isOpen())//如果所選擇的文件已經打開,則關閉掉
localFile->close();
clientConnection->abort();//clientConnection爲下一個連接?怎麼理解
}
close();//關閉本ui,即本對話框
}
// 被對方拒絕
void TcpServer::refused()
{
tcpServer->close();
ui->serverStatusLabel->setText(tr("對方拒絕接收!!!"));
}
// 關閉事件
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;
}
// 設置文件名
void TcpClient::setFileName(QString fileName)
{
localFile = new QFile(fileName);
}
// 設置地址
void TcpClient::setHostAddress(QHostAddress address)
{
hostAddress = address;
newConnect();
}
// 創建新連接
void TcpClient::newConnect()
{
blockSize = 0;
tcpClient->abort(); //取消已有的連接
tcpClient->connectToHost(hostAddress, tcpPort);//連接到指定ip地址和端口的主機
time.start();
}
// 讀取數據
void TcpClient::readMessage()
{
QDataStream in(tcpClient); //這裏的QDataStream可以直接用QTcpSocket對象做參數
in.setVersion(QDataStream::Qt_4_7);
float useTime = time.elapsed();
if (bytesReceived <= sizeof(qint64)*2) { //說明剛開始接受數據
if ((tcpClient->bytesAvailable() //bytesAvailable爲返回將要被讀取的字節數
>= sizeof(qint64)*2) && (fileNameSize == 0))
{
//接受數據總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)){
//開始接受文件,並建立文件
in>>fileName;
bytesReceived +=fileNameSize;
if(!localFile->open(QFile::WriteOnly)){
QMessageBox::warning(this,tr("應用程序"),tr("無法讀取文件 %1:\n%2.")
.arg(fileName).arg(localFile->errorString()));
return;
}
} else {
return;
}
}
if (bytesReceived < TotalBytes) {
bytesReceived += tcpClient->bytesAvailable();//返回tcpClient中字節的總數
inBlock = tcpClient->readAll(); //返回讀到的所有數據
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 已用時:%4秒\n估計剩餘時間:%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 完畢")
.arg(fileName));
}
}
// 錯誤處理
//QAbstractSocket類提供了所有scoket的通用功能,socketError爲枚舉型
void TcpClient::displayError(QAbstractSocket::SocketError socketError)
{
switch(socketError)
{
//RemoteHostClosedError爲遠處主機關閉了連接時發出的錯誤信號
case QAbstractSocket::RemoteHostClosedError : break;
default : qDebug() << tcpClient->errorString();
}
}
// 取消按鈕
void TcpClient::on_tcpClientCancleBtn_clicked()
{
tcpClient->abort();
if (localFile->isOpen())
localFile->close();
}
// 關閉按鈕
void TcpClient::on_tcpClientCloseBtn_clicked()
{
tcpClient->abort();
if (localFile->isOpen())
localFile->close();
close();
}
// 關閉事件
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 出處:http://www.cnblogs.com/tornadomeet 歡迎轉載或分享,但請務必聲明文章出處。