log4j.properties value filter

Question

Hi: I am using log4f for the logging in my app,and I want to add a FileAppender to the log,so I have to set the file:

log4j.appender.fileout.File=E:\myapp\logs\log.html

I wonder if there is any way can replace the absolute file path?

Maybe using something like:

log4j.appender.fileout.File={something}\logs\log.html?