Qt入门-文件读写

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：

ConstantValueDescriptionQIODevice::NotOpen0x0000The device is not open.QIODevice::ReadOnly0x0001The device is open for reading.QIODevice::WriteOnly0x0002The device is open for writing.QIODevice::ReadWriteReadOnly | WriteOnlyThe device is open for reading and writing.QIODevice::Append0x0004The device is opened in append mode, so that all data is written to the end of the file.QIODevice::Truncate0x0008If possible, the device is truncated before it is opened. All earlier contents of the device are lost.QIODevice::Text0x0010When 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::Unbuffered0x0020Any 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

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

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