Mega Code Archive
Count total number of live sessions in a web application
<![CDATA[
--- JSP page for testing (test.jsp) --
<%
Integer icount = (Integer)session.getAttribute("count");
out.println("total live sessions "+icount);
%>
--- Servlet that handles session count --
import javax.servlet.*;
import javax.servlet.http.*;
public final class CounterListener implements HttpSessionListener
{
private int count = 1;
private ServletContext context = null;
public synchronized void sessionCreated(HttpSessionEvent se)
{
count++;
log("sessionCreated("+se.getSession().getId()+") count="+count);
se.getSession().setAttribute("count",new Integer(count));
}
public synchronized void sessionDestroyed(HttpSessionEvent se)
{
count--;
log("sessionDestroyed("+se.getSession().getId()+") count="+count);
se.getSession().setAttribute("count",new Integer(count));
}
public int getCount()
{
return this.count;
}
public void addCount()
{
count++;
}
private void log(String message)
{
if (context != null)
context.log("SessionListener: " + message);
else
System.out.println("SessionListener: " + message);
}
}//close class CounterListener
--- web.xml file modification --
<?xml version="1.0" encoding="ISO-8859-1"?>
<!DOCTYPE web-app
PUBLIC "-//Sun Microsystems, Inc.//DTD Web Application 2.3//EN"
"http://java.sun.com/dtd/web-app_2_3.dtd">
<web-app>
<display-name>Welcome to Tomcat</display-name>
<!-- add this line of code -->
<listener>
<listener-class>CounterListener</listener-class>
</listener>
<description>
Welcome to Tomcat
</description>
</web-app>
]]>