Never edit icky JBoss XML files again!

By Shawn Hartsock (author)

Originally published April 16, 2010.

Do you have a JBoss application server? Do you have configuration files in that server that need to be edited or changed periodically? Do you have an allergy to XML?

Have I got a solution for you!

JBoss has the amazing ability to load *.properties files from any location (on the file system or on the internet) as part of its start up routine. So you can set properties in a simple properties file instead of an icky XML file.

NOTE: I’ll refer to the directory you have installed JBoss into as $JBOSS_HOME you may have your JBoss server installed in /opt/jboss or /usr/local/jboss for example. It doesn’t matter.

NOTE: I’ll assume your JBoss is set up to load the “default” server directory. If it isn’t then I think you are smart enough to figure out what to do on your own.

Stop the JBoss server
open the file $JBOSS_HOME/server/default/deploy/properties-service.xml in your favorite text editor.
Find the tag

<mbean code="org.jboss.varia.property.SystemPropertiesService"

  name="jboss:type=Service,name=SystemProperties">

Add this tag:

<attribute name="URLList">

      /etc/jboss/system.properties

</attribute>

Comment out or delete any other instances of the *...* tag

Great! Now when we start up the JBoss server again it will read the file /etc/jboss/system.properties and set its properties from there. But, wait… the file doesn’t exist yet. If I start my JBoss server and that file isn’t easily readable it will crash.

So let’s create the directory…

$ sudo mkdir -p /etc/jboss

… and the file …

$ sudo touch /etc/jboss/system.properties

… now we can restart JBoss safely.

We don’t get much benefit yet though. Nothing in JBoss is using that file. So let’s take a database-ds.xml file and configure it to use system.properties for its connector-url, user-name, and password.

Assuming you have a file like $JBOSS_HOME/server/default/deploy/database-ds.xml you can edit it to look like:

<?xml version="1.0" encoding="UTF-8"?>

<datasources>

   <local-tx-datasource>

      <jndi-name>MyDatabaseDS</jndi-name>

      <connection-url>**${MyDatabaseDS.connection-url}**</connection-url>

      <driver-class>**${MyDatabaseDS.driver-class}**</driver-class>

      <user-name>**${MyDatabaseDS.user-name}**</user-name>

      <password>**${MyDatabaseDS.password}**</password>

      <min-pool-size>10</min-pool-size>

      <max-pool-size>20</max-pool-size>

      <prepared-statement-cache-size>10</prepared-statement-cache-size>

   </local-tx-datasource>

</datasources>

Now edit /etc/jboss/system.properties to hold those values… it should look like this

# config for database-ds.xml

MyDatabaseDS.connection-url=jdbc:postgresql://localhost:5432/database

MyDatabaseDS.driver-class=org.postgresql.Driver

MyDatabaseDS.user-name=username

MyDatabaseDS.password=password

# this example is for postgresql but you could substitute any database.

… when you start up JBoss it will read the /etc/jboss/system.properties file and when it looks at database-ds.xml it will see the ${variable} values and substitute the values you set in system.properties for the ${variable}. If a ${variable} is not present, there will be no substitution… so be sure that every time you use a variable you set its value somewhere.

You can also set system wide system properties this way too. Commonly on servers that I work with the unix host name has nothing to do with the hostname being served. So I commonly set:


server.host=server.example.com

For use in my Grails applications which I then read in Config.groovy like this:


grails.serverURL = "https://${System.getProperty('server.host')}/${appName}"

… but that is another story …

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