How to create log file freshly every time I run my Java Program using Log4j?

Question

Currently I am using log4j for logging. It is generating the log file perfectly.But the problem is: whenever I run my program new logs which are generated are getting appended to already generated logs in the same file. Below is my log4j properties file:

log4j.rootCategory=INFO,LOGFILE

log4j.logger.org.apache.axis.enterprise=FATAL, LOGFILE

log4j.appender.LOGFILE = org.apache.log4j.DailyRollingFileAppender

log4j.appender.LOGFILE.File=applicationLogs.txt

log4j.appender.LOGFILE.Append = true

log4j.appender.LOGFILE.Threshold=DEBUG

log4j.appender.LOGFILE.DatePattern = \u2018.\u2019yyy-MM-dd

log4j.appender.LOGFILE.layout = org.apache.log4j.PatternLayout

log4j.appender.LOGFILE.layout.ConversionPattern = %d{yyyy-MM-dd HH:mm:ss} %c{1} [%p] %m%n

I need to generate a new log file every-time I run my program.How to do that? This file is perfect.But I want a slight modification.

Answer 1

Set the append to false, overwrite

log4j.appender.FILE.Append=false

This article helps you. https://www.tutorialspoint.com/log4j/log4j_logging_files.htm

Also this question will help you. One logfile per run with log4j

Answer 2

Take following steps:

1. log4j.appender.LOGFILE.File=applicationLogs_${current_date}.txt

2. log4j.appender.LOGFILE.Append=false.

For current_date to work edit your main class and add following code:

static{ SimpleDateFormat dateFormat = new SimpleDateFormat("dd-MM-yyyy hhmmss"); System.setProperty("current_date", dateFormat.format(new Date())); }

First setting will create a new log file each time your program starts depending on current date (so that you do not lose old logs) and by second setting it will not append to your old file but overwrite it.

You can use any one of the setting. First one is preferable as you are not losing your old logs.

Answer 3

In your code add something like below:

String today= Calendar.getInstance()
    .getTime()
    .toString()
    .replaceAll(" ", "_")
    .replaceAll(":", "");  
System.setProperty("logfilename", today);

and in your properties file:

log4j.appender.file.File=C:\\${logfilename}.log