Qt 文件处理

1.删除目录下所有的文件 

void deleteAllFiles(const QString& fileDir)
{
   
    
    QDir dir(fileDir);
    if(!dir.exists())
    {
        return;
    }
    
    QFileInfoList fileInfofList=dir.entryInfoList(QDir::Files | QDir::Hidden | QDir::NoDotAndDotDot | QDir::NoSymLinks | QDir::AllDirs);
    
    foreach (QFileInfo fileInfo, fileInfofList) 
    {
        if(fileInfo.isDir())
        {
           deleteAllFiles(fileInfo.absoluteFilePath()); 
        }
        else if(fileInfo.isFile())
        {
            QFile file(fileInfo.absoluteFilePath());
            file.remove();
        }
            
        
    }
   
    QDir tempDir;
    tempDir.rmdir(fileDir);//删除空的目录
}

删除超过多长时间的旧文件。toTime_t() 秒

const int OVERTIME=60*60*24*30;
void MainWindow::deleteOldFile(QString fileDir)
{
    QDir dir(fileDir);
    if(dir.exists())
    {
        dir.setFilter(QDir::Files | QDir::NoSymLinks);
        QDateTime nowDateTime = QDateTime::currentDateTime();
        QFileInfoList list = dir.entryInfoList();
        for (int i = 0; i < list.size(); ++i)
        {
            QFileInfo fileInfo = list.at(i);
            //秒
            int passTime=nowDateTime.toTime_t()-fileInfo.created().toTime_t();
            if(passTime>OVERTIME)
            {
                QFile file(fileInfo.absoluteFilePath());
                file.remove();
            }
            

        }
    }
}

 QString fileDir="/home/likewei/公共的/dispatch_log";

 deleteOldFile(fileDir);

2.读文件 

 QFile file(yamlFile);
    if (!file.open(QIODevice::ReadOnly | QIODevice::Text)) {
        log::d("yamle open file fail!");
        return false;
    }

    QTextStream in(&file);
    while (!in.atEnd()) {
        QString line = in.readLine();
        log::d(line);
    }
    file.close ();

2.QWidgetList导出excel

void ReportDlg::onExport()
{

     QString file_path = QFileDialog::getSaveFileName(this,"Excel file",qApp->applicationDirPath(),
                                                       tr("Files (*.csv)"));


       if(file_path.isEmpty())
       {
           return;
       }

       QFile file(file_path);
       if(!file.open(QIODevice::WriteOnly | QIODevice::Text))
       {
            qDebug()<< "Cannot open file for writing";

            return;
       }

       QTextStream out(&file);
       int row_count=tw->rowCount();
       int col_count=tw->columnCount();
       QString tw_value;


       for(int h=0;h<col_count;h++)
       {

           tw_value=tw->horizontalHeaderItem(h)->text();
           out<<tw_value<<",";
       }
       out<<"
";
       for(int i=0;i<row_count;i++)
       {

           for(int j=0;j<col_count;j++)
           {

               tw_value=tw->item(i,j)->text();
               out<<tw_value<<",";
           }
           out<<"
";
       }

       file.close();


}

 3.记录错误信息，每天用新的文件记录信息，以防止记录的信息太多。

void MainWindow::log(QString msg)
{

    QString fileName=QDateTime::currentDateTime ().toString ("yyyy_MM_dd")+".log";
    QString currentDir= QCoreApplication::applicationDirPath()+"/logs";

    QDir dir;
    if(!dir.exists (currentDir))
    {
        dir.mkpath (currentDir);
    }
    fileName=currentDir+"/"+fileName;

    QFile file(fileName);
    if(!file.exists (fileName))
    {
        file.setFileName (fileName);
    }
    file.open(QIODevice::WriteOnly|QFile::Append);
    QTextStream in(&file);  
    in<<QDateTime::currentDateTime ().toString ("[hh:mm:ss:zzz]")+" "+msg+"
";
    file.close ();

}

 4.选择文件对话框

 QString defaultDir=QCoreApplication::applicationDirPath()+"/data";
    QString fileName= QFileDialog::getOpenFileName(
                this,
                "Import File",
                defaultDir,
                "file (*.txt *.bin);;all files (*.*)");
    if(!fileName.isEmpty())
    {
       emit sigImportFile(fileName);
    }

5.在指定的目录查找指定的文件

 QString binFileDir=QCoreApplication::applicationDirPath()+"/file";
    QDir *dir=new QDir(binFileDir);
    if(!dir->exists())
    {
        qDebug()<<"no found dir";
        return -1;
    }

    //只查找设置过滤的文件，指定多个过滤，这样写filter<<"*.dat"<<"*.txt
    QStringList filter;
    filter<<"*.bin";
    dir->setNameFilters(filter);
    QList<QFileInfo> *fileInfo=new QList<QFileInfo>(dir->entryInfoList(filter));
    int fileCount=fileInfo->count();
    qDebug()<<"fileCount"<<fileCount;
    for(int i=0;i<fileCount;i++)
    {
        qDebug()<<"fileName:"<<fileInfo->at(i).fileName();
        qDebug()<<"filePath:"<<fileInfo->at(i).filePath();

    }