Getting a list of active sessions in Tomcat using Java

Question

I am developing a project in Java in which I want the count of all active sessions in Tomcat. Based on that I want to see how much of those users are active and actually usi

Answer 1

"PSI Probe" may do the trick for you: http://code.google.com/p/psi-probe/

Answer 2

Here is the Java 7 style JMX code snippet (what basZero asked for and exactly does the job what Janning described):

JMXServiceURL url = new JMXServiceURL("service:jmx:rmi:///jndi/rmi://localhost:9999/jmxrmi");
try(JMXConnector jmxc = JMXConnectorFactory.connect(url)) {
  MBeanServerConnection mbsc = jmxc.getMBeanServerConnection();
  ObjectName mbeanName = new ObjectName("Catalina:type=Manager,context=/,host=localhost");
  Object value = mbsc.getAttribute(mbeanName, "activeSessions");
}

Of course you need to replace root context (/) in ObjectName with your app context string if it is not deployed in the root context. See my detailed explanation on the Catalina JMX issue here: Accessing built-in MBeans in Tomcat programatically

Answer 3

There isn't any way to get the session count directly from tomcat. But you can create and register a session listener and up the count when its created. Here is an example:

http://tomcat-configure.blogspot.com/2009/01/tomcat-session-listener-example.html

public class SessionCounter implements HttpSessionListener {

  private static int activeSessions = 0;

  public void sessionCreated(HttpSessionEvent se) {
    activeSessions++;
  }

  public void sessionDestroyed(HttpSessionEvent se) {
    if(activeSessions > 0)
      activeSessions--;
    }

  public static int getActiveSessions() {
     return activeSessions;
  }
}