java - How to use system environment variables in log4j.properties?

Question

I added the system environment value PROJECT_HOME=C:Program FilesProject

Now i'm trying to use the system environment value in log4j.properties but didn't set it

**log4j.properties**
**log4j.appender.LOGFILE.File="${env.PROJECT_HOME}"/project.log**

Could you please tell me how to set system environment variables in log4j.properties?

Using log4j-1.2.7 version

Answer 1

This is supported by EnvironmentLookup in log4j - 2. See examples.

Use ${sys:PROJECT_HOME} instead of ${env.PROJECT_HOME}