WebSphere Application Server V7.0: Concepts ... - IBM Redbooks

A lesser known, but better, approach to access property files is to use URL
resources. We do not go into the details of exactly how to do that here, but the
following steps describe the approach:
1. Create a folder on your system that holds the property file.
2. Use the Integrated Solutions Console and create a URL resource that points
to the property file and assign it a JNDI name.
3. In the application, create a URL resource reference binding pointing to the
JNDI name chosen.
4. In Java, use JNDI to look up the URL resource reference. Create an
InputStream from the URL, and use that InputStream as input to the
java.util.Properties class to load the property files.
This approach to access property files is also more Java EE compliant because it
does not rely on the java.io package for file access, which is prohibited according
to the Java EE specification.
The method also gives you the opportunity to load the property files using HTTP
and FTP. This allows you to set up an HTTP server serving properties files from a
central location.
Unless you are using the previous technique with the HTTP or FTP protocol, it is
convenient to manage all property files in a central location, on the deployment
manager. However, property files stored in folders outside the EAR files are not
propagated to the WebSphere nodes unless the folders are created under the
deployment manager cell configuration folder, which is
\config\cells\.
By creating a folder, such as appconfig, under this folder, you can take advantage
of the WebSphere file transfer service to propagate your files to the nodes.
Because this folder is not known to the WebSphere Application Server
infrastructure, it will not happen automatically when the contents are changed.
You need to force a synchronization with the nodes. This propagates the property
files to the \config\cells\\appconfig directory on each
node. You can include that folder on the class path using a shared library or point
your URL resources to it.
Tip: When deciding on names for settings in property files, it is a good idea to
include the unit of the setting referred to in the name. Therefore, instead of
using MaxMemory or Timeout, it is better to use MaxMemoryMB and
TimeoutMS to indicate that the max memory should be given as megabytes
and the timeout as milliseconds. This can help reduce confusion for the
system administrator who does not know the internals of the application.
304 WebSphere Application Server V7.0: Concepts, Planning, and Design