各位大佬，如何让软件生成日志文件?

亭台六七座 2020-03-29 03:08:13

各位大佬，如何让软件生成日志文件?

需要写很多 qDebug()吗？

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苏州安瑞软件有限公司 2020-04-24

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void MvPublic::Createlog(QString  filepath, int nums)

{

   logfilePath = filepath;  //全局私有变量,日志路径-格式为 C:/MVLOG/ContraolBoard

   QDir filedir(filepath);

   if (filedir.exists())     //如果路径存在，删除老的老的日志文件

   {

       QFileInfoList filelist = filedir.entryInfoList(QDir::Files,QDir::Name);  //过滤当前路径下的文件并排序

       if(filelist.count()>nums)

       {

           QStringList logfilelist;

           for(int i=0;i<filelist.count();i++)

           {

               if(QString::compare(filelist[i].suffix(),"log",Qt::CaseSensitive)==0) //判断是否为日志文件

               {

                   logfilelist.append(filelist[i].path());

               }

           }

           if(logfilelist.count()>nums) //判断数量是否大于指定保存数量

           {

               for(int i=0;i<logfilelist.count()-nums;i++)

                   filedir.remove(logfilelist[i]);   //删除多余的日志文件

           }

       }

   }

   else

       filedir.mkpath(filepath); //不存在就创建路径



   logfileName =  logfilePath+"/"+QString(QDateTime::currentDateTime().toString("yyyyMMdd"))+".log";

   logfile.setFileName(logfileName);

   logfile.open(QIODevice::WriteOnly|QIODevice::Append);

   logStream.setDevice(&logfile);

   Writlog("*****************应用程序启动*****************");

}





void MvPublic::Writlog(QString sloginfo)

{

  logMutex.lock();

  QString Currentfilename = logfilePath+"/"+QString(QDateTime::currentDateTime().toString("yyyyMMdd"))+".log";

  if (Currentfilename!=logfileName) //新的一天，重新创建一个文件

  {

      logfile.close();

      logfileName=Currentfilename;

      logfile.setFileName(logfileName);

      logfile.open(QIODevice::WriteOnly|QIODevice::Append);

  }

  sloginfo = "["+QString(QDateTime::currentDateTime().toString("hh:mm:ss:zzz"))+"] "+sloginfo;

  logStream<<sloginfo<<"\r\n";

  logStream.flush();

  logfile.flush();

  logMutex.unlock();

}

scribbler 2020-04-23

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拦截消息



static void messageOutput(QtMsgType type, const QMessageLogContext &context, const QString &msg);

qInstallMessageHandler(messageOutput);

static void writeLogFile(const QString &msg);

static QString getLogFilePath();

static void messageOutput(QtMsgType type, const QMessageLogContext &context, const QString &msg)

{

    static QMutex mutex;

    mutex.lock();

    QByteArray localMsg = msg.toUtf8();

 switch (type)

    {

    case QtDebugMsg:

    case QtInfoMsg:

    case QtWarningMsg:

        if( debug )

        {

            fprintf(stdout, "%s\n", QVariant(localMsg).toString().toUtf8().constData());

            fflush(stdout);

        }

        break;

    case QtCriticalMsg:

        if( debug )

        {

            fprintf(stderr, "%s\n", QVariant(localMsg).toString().toUtf8().constData());

            fflush(stderr);

        }

        break;

    case QtFatalMsg:



        fprintf(stderr, "%s\n", QVariant(localMsg).toString().toUtf8().constData());

        fflush(stderr);

        break;

        // abort();

    }

    writeLogFile(text);

    mutex.unlock();

}

static void writeLogFile(const QString &msg)

{

    if(qApp==nullptr)

    {

        return;

    }



    QString path = getLogFilePath();

    QLocale lo(QLocale::C);

    QDateTime dateTime = QDateTime::currentDateTimeUtc();

    dateTime = dateTime.toLocalTime();

    QString name = lo.toString(dateTime, "yyyyMMdd.log");



    QString filePath = path + name;



    QFile file(filePath);

    if(!file.exists ())

    {

        file.open(QIODevice::WriteOnly);

        file.close();

    }

    if(file.open(QIODevice::WriteOnly | QIODevice::Append))

    {

        QTextStream stream(&file);

        stream << msg << "\r\n";

        file.flush();

        file.close();

    }

}

static QString getLogFilePath()

{

    QString logPath = QString::fromStdString(Application::GetCurrentApplicationSupportDirectory());



    logPath = logPath + QDir::separator() + "logs" + QDir::separator();



    QDir dir(logPath);

    if(!dir.exists(logPath))

    {

        dir.mkpath(logPath);

    }

    return logPath;

}

未狂 2020-04-21

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qDebug可以增加一个控制，让qDebug实现日志功能


#include "widget.h"
#include <QApplication>
#include <iostream>
#include <cstdlib>
#include <QFile>
#include <QString>
#include <QTextStream>
#include <QMutex>
#include <QDateTime>
using namespace std;

QMutex mutex;//日志代码互斥锁
QString timePoint;

//日志生成
void LogMsgOutput(QtMsgType type, const QMessageLogContext &context, const QString &msg)
 {	 
	 mutex.lock();
	 cout << msg.toStdString() << endl;
	 //Critical Resource of Code
     QByteArray localMsg = msg.toLocal8Bit();
	 QString log;
	 
     switch (type) {
     case QtDebugMsg:
         //fprintf(stderr, "Debug: %s (%s:%u, %s)\n", localMsg.constData(), context.file, context.line, context.function);
		 log.append(QString("Debug  File:%1 %2  Line:%3  Content:%4").arg(context.file).arg(context.function).arg(context.line).arg(msg));
         break;
     case QtInfoMsg:
         //fprintf(stderr, "Info: %s (%s:%u, %s)\n", localMsg.constData(), context.file, context.line, context.function);
		 log.append(QString("Info: %1  %2  %3  %4").arg(localMsg.constData()).arg(context.file).arg(context.line).arg(context.function));
         break;
     case QtWarningMsg:
         //fprintf(stderr, "Warning: %s (%s:%u, %s)\n", localMsg.constData(), context.file, context.line, context.function);
		 log.append(QString("Warning: %1  %2  %3  %4").arg(localMsg.constData()).arg(context.file).arg(context.line).arg(context.function));
         break;
     case QtCriticalMsg:
         //fprintf(stderr, "Critical: %s (%s:%u, %s)\n", localMsg.constData(), context.file, context.line, context.function);
		 log.append(QString("Critical: %1  %2  %3  %4").arg(localMsg.constData()).arg(context.file).arg(context.line).arg(context.function));
         break;
     case QtFatalMsg:
         //fprintf(stderr, "Fatal: %s (%s:%u, %s)\n", localMsg.constData(), context.file, context.line, context.function);
		 log.append(QString("Fatal: %1  %2  %3  %4").arg(localMsg.constData()).arg(context.file).arg(context.line).arg(context.function));
         abort();
     }
	 
	 QFile file;
	 QString path = QString("log%1.lgt").arg(timePoint);
	 file.setFileName(path);
	 if (!file.open(QIODevice::ReadWrite | QIODevice::Append))
	 {
		 QString erinfo = file.errorString();
		 cout << erinfo.toStdString() << endl;
		 return;
	 }
	 QTextStream out(&file);
	 out << "\n\r" << log;
	 file.close();

	 mutex.unlock();
 }

int main(int argc, char *argv[])
{
	//release模式下，调试信息输出至日志文件
#ifndef _DEBUG
	timePoint = QDateTime::currentDateTime().toString("yyyyMMddHHmmss");
	qInstallMessageHandler(LogMsgOutput);
#endif
    QApplication a(argc, argv);
    Widget w;
    w.show();

    return a.exec();
}

smile_sambery 2020-04-12

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class Log {
public:
enum logLevel {
debug,
info,
warning,
error
};
static log* getinstance(){
//写一个单例类
}
void saveLogToFile(logLevel level, QString logInfo){
//判断log等级
//上锁
//打开文件，并写入数据
//关闭文件
//解锁
}
private:
Log() {
//创建log文件
}
static log *logSingleInstance;
logLevel m_logLevel;
QString logPath;
};

smile_sambery 2020-04-12

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可以写一个相关的log单例类，log构造函数中做创建一个保存log的文件，再在类中写一个方法，主要是将需要保存的数据写入文件操作，这样的话就能在任何地方调用单例类的方法来将log信息保存到文件中了。如果牵涉到多线程中的log保存问题，则需要在文件操作过程中加入锁的机制。
具体伪代码如下
class Log {
public:
static log* getinstance(){
}
void saveLogToFile(logLevel level, QString logInfo){

private:
Log();
static log *logSingleInstance;
};