Setting environment variable for service

Question

I am running tomcat on a windows 2012 machine.

I need to set an environment variable before the service starts such that I can query the variable in Java in the web application like this:

String myVar = System.getenv("MY_VAR"); 

This variable is NOT a tomcat variable. It is a variable specific to our application.

I am not including tomcat in the tag for this question because this applies to any service; however, I would be happy with a tomcat specific answer.

Here is the question where I asked for a tomcat specific solution: https://superuser.com/questions/1142406/setting-user-environment-variables-for-tomcat-on-windows

I am using the stand way that Windows manages services that is accessed from the "Administrative Tools" -> "Services" to start and stop tomcat. So AFAIK, I don't have the usual control I have where I could put the environment variable in a .bat file that also starts the server process.

Answer 1

If you want to set an environment variable just for the service (regardless of what user it's running as) you can do so in the registry: HKLM\SYSTEM\CurrentControlSet\Services.

Here's a quick example of using regedit to add two environment variables to the Windows Update service (just for demonstration purposes, these aren't affecting the service):

• FOO=Bar
• KEY=SGVsbG8gV29ybGQhIQ==

Start (or restart, if it's already running) the service. We can then use Process Explorer to see that the environment variables are available:

Answer 2

If it is a local Server 2012 environment variable you seek, you can use PowerShell to create a new system or user environment variable make sure you run PowerShell as Administrator.

Machine variable:
[Environment]::SetEnvironmentVariable('Name','Value','Machine')
User variable:
[Environment]::SetEnvironmentVariable('Name','Value','User')

To check the current environment variables, use the following PowerShell command

Get-Childitem ENV: 

Note: you will need to close PowerShell and open a new instance to see the newly created environment variable.