get environment var in servlet

[zhebincong]

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.

[sigrney]

I don't believe Java security features will allow you to get a handle on the jboss home dir environment variable with pure Java, but the standard way of getting the java home dir is like this:

String javaHome = System.getProperty("java.home");

See this Java tutorial page for more system properties you can use:

http://java.sun.com/docs/books/tutorial/essential/system/properties.html