转载：http://blog.csdn.net/xgbing
二进制文件的读写文件可以使用QFile类、QStream
文本文件的读写建议使用QTextStream类，它操作文件更加方便。
打开文件时，需要参数指定打开文件的模式：
[plain] view plain copy Constant Value Description QIODevice::NotOpen 0x0000 The device is not open. QIODevice::ReadOnly 0x0001 The device is open for reading. QIODevice::WriteOnly 0x0002 The device is open for writing. QIODevice::ReadWrite ReadOnly | WriteOnly The device is open for reading and writing. QIODevice::Append 0x0004 The device is opened in append mode, so that all data is written to the end of the file. QIODevice::Truncate 0x0008 If possible, the device is truncated before it is opened. All earlier contents of the device are lost. QIODevice::Text 0x0010 When reading, the end-of-line terminators are translated to '\n'. When writing, the end-of-line terminators are translated to the local encoding, for example '\r\n' for Win32. QIODevice::Unbuffered 0x0020 Any buffer in the device is bypassed.QIODevice::Text在读写文本文件时使用，这样可以自动转化换行符为本地换行符。
(1)写入文本文件
[cpp] view plain copy QFile f("c:\\test.txt"); if(!f.open(QIODevice::WriteOnly | QIODevice::Text)) { cout << "Open failed." << endl; return -1; } QTextStream txtOutput(&f); QString s1("123"); quint32 n1(123); txtOutput << s1 << endl; txtOutput << n1 << endl; f.close();写入的文件内容为：
123
123
(2)读取文本文件
[cpp] view plain copy QFile f("c:\\test.txt"); if(!f.open(QIODevice::ReadOnly | QIODevice::Text)) { cout << "Open failed." << endl; return -1; } QTextStream txtInput(&f); QString lineStr; while(!txtInput.atEnd()) { lineStr = txtInput.readLine(); cout << lineStr << endl; } f.close(); 屏蔽打印的内容为：123
123
