Qt下的log日志

#include <QApplication>
#include <QTextCodec>
#include <QDateTime>
#include <QFile>
#include <QTextStream>
#include <QMutex>

void outputMessage(QtMsgType type, const QMessageLogContext &context, const QString &msg)
{
    static QMutex mutex;
    mutex.lock();

    QString text;
    switch(type)
    {
    case QtDebugMsg:
        text = QString("Debug:");
        break;

    case QtWarningMsg:
        text = QString("Warning:");
        break;

    case QtCriticalMsg:
        text = QString("Critical:");
        break;

    case QtFatalMsg:
        text = QString("Fatal:");
    }

    QString context_info = QString("File:(%1) Line:(%2)").arg(QString(context.file)).arg(context.line);
    QString current_date_time = QDateTime::currentDateTime().toString("yyyy-MM-dd hh:mm:ss ");
    QString current_date = QString("(%1)").arg(current_date_time);
    //QString message = QString("%1 %2 %3 %4").arg(current_date).arg(text).arg(context_info).arg(msg);
    QString message = QString("%1 %2 %3").arg(current_date).arg(text).arg(msg);

    QString timestr=QDateTime::currentDateTime().toString("yyyy-MM-dd");
    QString fileName = timestr + ".txt";//假设指定文件夹路径为D盘根目录

    QFile file(fileName);
    file.open(QIODevice::WriteOnly | QIODevice::Append);
    QTextStream text_stream(&file);
    text_stream << message << "\r\n";
    file.flush();
    file.close();

    mutex.unlock();
}



int main(int argc, char *argv[])
{
    QApplication a(argc, argv);
    //注册MessageHandler
    qInstallMessageHandler(outputMessage);

    //打印日志到文件中

      qDebug("This is a debug message");
      qWarning("This is a warning message");
      qCritical("This is a critical message");
      //qFatal("This is a fatal message");


    //Dialog w;
    //w.show();

    return a.exec();
}