where/how to setup configuration resources for Tomcat .war files

Question

I have a source tree for a .war file that I need to modify so that I can add some application-specific configuration info (in this case a jdbc connection string, but I may have other properties-like resources). What are the best practices for where to put configuration info and how to access this from within the Servlet?

I'm guessing this Tomcat configuration reference has something to do with it, but my eyes glaze over when I try to read it.

Answer 1

For web app configuration you can place the config on the classpath somewhere. Then you can get to it from your application with getResourceAsStream or if you prefer Spring:

<bean class="org.springframework.beans.factory.config.PropertyPlaceholderConfigurer">
  <property name="locations">
    <list>
      <value>classpath:my-config.properties</value>
    </list>
  </property>
</bean>

There are a number of places you can put the properties on the classpath in Tomcat. in order it looks at:

/WEB-INF/classes of your web application 
/WEB-INF/lib/*. jar of your web application 
$CATALINA_HOME/common/classes 
$CATALINA_HOME/common/endorsed/*.jar 
$CATALINA_HOME/common/i18n/*.jar 
$CATALINA_HOME/common/lib / *. jar 
$CATALINA_BASE/shared/classes 
$CATALINA_BASE/shared/lib/*.jar  

For example, if you put my-config.properties both in a .jar file and in WEB-INF/classes the one in WEB-INF/classes will be used. You could use this mechanism to default to test config and override prod config on prod servers.