How to set environment variables in JBoss

We are developing an application that is deployed in a JBoss. we would like to define a properties files like this:

URL_DEVELOPMENT.properties = ...
URL_TEST.properties = ...
URL_PRODUCTION.properties = ...

and define an environment variable in the JBoss which contains the information about the execution context

for example --> ENVIRONMENT = DEVELOPMENT

Anyone knows:

1) How to set environment variables in JBoss.

2) How to get these variables from an applicacion deployed in JBoss in runtime execution?

Thank you !