log4j log file in user home directory

Question

I am working on an application that will run on OSX and windows. I want the logs to be written to the users home directory. For OSX it will be under the /Users//Library/Applicat

Answer 1

Possibly the cleanest approach would be to write your log4j configuration assuming a particular system property (say myapp.data.dir)

log4j.appender.logfile.fileName=${myapp.data.dir}/logs/myapp.log

and set that property in the appropriate way in the launcher for each platform. For example if you're using an .app bundle on Mac OS X then you can set system properties in Info.plist

    
    Java
    
        
        Properties
        
            apple.laf.useScreenMenuBar
            true
            myapp.data.dir
            $USER_HOME/Library/Application Support/MyApp

or set it relative to the APPDATA environment variable on Windows (which would handle the difference between XP and 7). With a Launch4J .exe you could put -Dmyapp.data.dir="%APPDATA%\MyApp" in the .l4j.ini file.

You'd need explicit code to initialize log4j before you try and access any loggers

if(System.getProperty("myapp.data.dir") == null) {
  // fallback to ~/.myapp (sensible Linux default) if run without a launcher
  System.setProperty("myapp.data.dir", new File(
        System.getProperty("user.home"), ".myapp").getAbsolutePath());
}
// ensure log directory exists
new File(new File(System.getProperty("myapp.data.dir")), "logs").mkdirs();
// now it's safe to configure log4j
PropertyConfigurator.configure(this.getClass().getResource("/log4j.properties"));