ServletContextListener handles ServletContextEvents.
ServletContextEvent notifies the creation or deletion of context.
Methods:
contextInitialized(ServletContextEvent sce)
contextDestroyed(ServletContextEvent sce)
The listener is for setting common information in the application.
The information set in it can be used in everypage.
In a distributed environment, a ServletContext is created in each JVM, and therefore setting global information in the ServletContext attributes is not recommended.
＜Sample＞
web.xml
<listener>
<display-name>Context Listener</display-name>
<listener-class>listener.ListenerSample1</listener-class>
</listener>
_________
ListenerSample.java
public class ListenerSample1 implements ServletContextListener {
public void contextInitialized(ServletContextEvent sce) {
ServletContext context = sce.getServletContext();
context.setAttribute("message", "Good Morning");
}
public void contextDestroyed(ServletContextEvent sce) {
ServletContext context = sce.getServletContext();
context.removeAttribute("message");
}
}
_________
sample.jsp
<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>
<html>
<body>
<c:out value="${applicationScope.message}" />
</body>
</html>
＜Result＞http://localhost:8080/SCWCD/sample.jsp
Good Morning
5/20/2009
Listener
Listeners are used for notifying ivents in the web applicaion.
Listeners must be defined in the web.xml except listeners that implement HttpSessionBindingListener and HttpSessionActivationListener are excluded
Example
web.xml
<listener>
<listener-class>sample.MyListener1</listener-class>
</listener>
Listeners must be defined in the web.xml except listeners that implement HttpSessionBindingListener and HttpSessionActivationListener are excluded
Example
web.xml
<listener>
<listener-class>sample.MyListener1</listener-class>
</listener>
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