Spring Framework

org.springframework.web.util
Class WebAppRootListener

java.lang.Object
  extended by org.springframework.web.util.WebAppRootListener
All Implemented Interfaces:
java.util.EventListener, javax.servlet.ServletContextListener

public class WebAppRootListener
extends java.lang.Object
implements javax.servlet.ServletContextListener

Listener that sets a system property to the web application root directory. The key of the system property can be defined with the "webAppRootKey" init parameter at the servlet context level (i.e. context-param in web.xml), the default key is "webapp.root".

Can be used for toolkits that support substition with system properties (i.e. System.getProperty values), like log4j's "${key}" syntax within log file locations.

Note: This listener should be placed before ContextLoaderListener in web.xml, at least when used for log4j. Log4jConfigListener sets the system property implicitly, so there's no need for this listener in addition to it.

WARNING: Some containers, e.g. Tomcat, do NOT keep system properties separate per web app. You have to use unique "webAppRootKey" context-params per web app then, to avoid clashes. Other containers like Resin do isolate each web app's system properties: Here you can use the default key (i.e. no "webAppRootKey" context-param at all) without worrying.

WARNING: The WAR file containing the web application needs to be expanded to allow for setting the web app root system property. This is by default not the case when a WAR file gets deployed to WebLogic, for example. Do not use this listener in such an environment!

Since:
18.04.2003
Author:
Juergen Hoeller
See Also:
WebUtils.setWebAppRootSystemProperty(javax.servlet.ServletContext), Log4jConfigListener, System.getProperty(java.lang.String)

Constructor Summary
WebAppRootListener()
           
 
Method Summary
 void contextDestroyed(javax.servlet.ServletContextEvent event)
           
 void contextInitialized(javax.servlet.ServletContextEvent event)
           
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Constructor Detail

WebAppRootListener

public WebAppRootListener()
Method Detail

contextInitialized

public void contextInitialized(javax.servlet.ServletContextEvent event)
Specified by:
contextInitialized in interface javax.servlet.ServletContextListener

contextDestroyed

public void contextDestroyed(javax.servlet.ServletContextEvent event)
Specified by:
contextDestroyed in interface javax.servlet.ServletContextListener

Spring Framework