How to get environment variable ?

[Nathan KV]

i am setting the environment variable in dos by giving the following command.
set empid=1001
how to get the value of empid in my java program ?
Thx in advance.
Nathan

[Ta Ri Ki Sun]

use System.getProperty/ies

[Michael Morris]

Greetings Nathan,
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[Michael Morris]

use System.getProperty/ies

That won't work since the System properties file is limited to environment variables which are required by the VM and core Java API. I'm afraid that you are limited to a couple of options, first write an native method to retrieve the dos environment, or write a simple batch file and parse the output. Here is an example of the second method:
GetEnvVar.java

import java.util.*;
import java.io.*;
public class GetEnvVar {
    public static void main(String[] args) throws IOException {
        Process getEnv = Runtime.getRuntime().exec("GETENVVAR.BAT");
        BufferedReader in = new BufferedReader(
                            new InputStreamReader(getEnv.getInputStream()));
        String line = null;
        while ((line = in.readLine()) != null) {
            StringTokenizer st = new StringTokenizer(line, "=");
            if (st.hasMoreTokens()) {
                if (st.nextToken().equals("USERNAME") && st.hasMoreTokens()) {
                    System.out.println(st.nextToken());
                }
            }
        }
    }
}

GETENVVAR.BAT

SET USERNAME

And here is the output:

mike

Michael Morris

[Eddie Sheffield]

Originally posted by Taariq Levack:
use System.getProperty/ies

As Michael said this works for the "default" environment variables. However it also works for system variables defined on the command line when the app is run. So for example you could run the app as:

java -Dusername=%USERNAME% com.myapp.Main

You would then have the system property "username" defined inside your app. You can include as many "-Dname=value" pairs as you want (subject to OS command line length limits ) This would be the Windows way of running it. You can do something similar in *nix. A batch file or shell script to start up the app is helpful. Do some searching on the web - this is an old problem and you should be able to find several solutions. I think I've even seen generic batch/shell scripts that would add all available env vars to the command line, but that may be overkill.
Good luck!
[ April 01, 2003: Message edited by: Eddie Sheffield ]