QThread 退出时如何自动释放资源
QThread退出时,会自动发送信号finished(),获取这个信号,连接到deleteLater()函数即可。

ThreadSync *threadSync = new ThreadSync();  //自定义继承自QThread的线程
connect(threadSync, SIGNAL(finished()),threadSync, SLOT(deleteLater()));
threadSync->filePath = filePath;
threadSync->start();