#include <QDir>　／／头文件

QDir *TEST = new QDir;
    bool exist = TEST->exists("TEST");
    if(!exist)
    bool ok = TEST->mkdir("TEST");
   QString fileName = "TEST/1.txt";　　
   QString str="今天的天气很好适合跑步";
   QFile file(fileName);
   if(!file.open(QIODevice::WriteOnly  | QIODevice::Text|QIODevice::Append))
   {
        qDebug() << "open fail!" << endl;
   }
   QTextStream in(&file);
   in<<":"+str<<"\n";
   file.close();