I usually put a properties file someone in the web application then use a
"startup servlet" that loads it.  The startup servlet has an init-param
pointing at the file.  Once I've created the properties file, I put it in an
environment object that is shared by everyone.

   try {

     String propsFile = config.getInitParameter("application.properties");

     if (propsFile != null) {
       Properties properties = new Properties();
       properties.load(context.getResourceAsStream(propsFile));
       Environment.initialize(properties);
     } else {
       throw new Exception("Couldn't find application.properties.");
     }

   } catch (Exception e) {
     logger.error("Couldn't load application properties.", e);
     throw new UnavailableException("Couldn't load application
properties.");
   }

I place mine in the WEB-INF/web.xml deployment descriptor for the web
application.

For example:

in WEB-INF/web.xml (in between the <webapp> </webapp> tag)

<env-entry>
   <env-entry-name>docBase</env-entry-name>
   <env-entry-value>doc1</env-entry-value>
   <env-entry-type>java.lang.String</env-entry-type>
</env-entry>

<env-entry>
   <env-entry-name>docBaseUser</env-entry-name>
   <env-entry-value>munroeb</env-entry-value>
   <env-entry-type>java.lang.String</env-entry-type>
</env-entry>

In the servlet or JavaBean that I need the resources:

Context env = (Context) new InitialContext().lookup("java:comp/env");
String docBase = (String) env.lookup("docBase");
String docBaseUser = (String) env.lookup("docBaseUser");