Re: Obtaining a list of all active sessions within a Servlet container.

Robert Klemme <>
Mon, 14 Apr 2008 20:54:54 +0200
On 14.04.2008 09:41, wrote:

Hi Theo,

  Use HttpSessionActivationListener as follows for your requirement,


class SessionCounterListener implements HttpSessionActivationListener

  public static final Map activeSessions = HashMap<String,

  public void sessionDidActivate(HttpSessionEvent event) {
    HttpSession session = event.getSession();
    activeSessions.put(session.getId(), session);

  public void sessionWillPassivate(HttpSessionEvent event) {
    HttpSession session = event.getSession();


Define the above listener in web.xml as,

Use below code to get the active sessions,

SessionCounterListener.activeSessions.size() - Returns the number of
active sessions.
SessionCounterListener.activeSessions.getValues() - Returns the all
the active sessions.

.... and don't forget proper synchronization.



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