Getting OS environment variables

[Walter Chen]

Hi, all:

I am having difficulty getting OS environment variables inside a J2EE app. For example, on Windows, the TEMP variable is defined as "C:\temp" -- you can see this by typing "set" on any command prompt window. I want to retrieve it from the java code (running on an app server), but System.getProperties does not return it. What is the best way to get it?

Thanks,
Walter

[Scott Johnson]

System.getProperties() is used to retrieve system properties which are different than environment variables.

System.getenv() or System.getenv(String) can be used to retrieve environment variables.
[ June 27, 2006: Message edited by: Scott Johnson ]

[Walter Chen]

Thanks for the reply but getEnv has been deprecated and the API says use getProperty or getProperties, but those do get the OS environment variables that I want.

[Scott Johnson]

It's true that getenv(String) was deprecated in Java 1.4.2 (and some earlier versions).

But in Java 1.5 it's no longer deprecated. In fact, Sun added a new method

static Map<String,String> getenv()

In Java 1.4.2, Sun did recommend using the System.getProperty() methods instead of getenv(). But the JVM does not make enviroment variables available through System.getProperty(). You must pass the JVM any value to be set as a system property. They can be passed on the JVM command line (with the -D parameter) or set in your app server config.