get the environment var in the servlet

[zb cong]

hello
in my servlet,there is following code block:
File f=new File("%JAVA_HOME%\\test.txt");
f.createNewFile();
the "JAVA_HOME" is the environment variable of my windows.after i deploy it to jboss,it threw exception.that tell me can't find the path.
then i modify it as:
File f=new File("%JBOSS_HOME%\\test.txt");
f.createNewFile();
the "JBOSS_HOME" is definde in its "run.bat " file.
the code still don't work.
who can tell me :
1 how can i use the environment variable of os or app server?
2 how and where can i set up a envrionment variable as the base dir ?
thank you.

[Bear Bibeault]

There's no supported way to get the value of environment variables in Java. You'd be better off setting up a context-level init param in your web.xml for these types of config variables.

[zb cong]

thanks