"Java EE Enterprise Application Combat Learning record" Sessionlistener

1 Package Sanglp.servlet;2 3 4 import Javax.servlet.ServletContext;5 import Javax.servlet.annotation.WebListener;6 import javax.servlet.http.HttpSession;7 import javax.servlet.http.HttpSessionEvent;8 import java.util.Hashtable;9 import Java.util.Map;Ten  One /** A * Created by Administrator on 2016/10/6. -  */ - @WebListener the  Public classHttpsessionlistener implements Javax.servlet.http.HttpSessionListener { -  -     //This method is triggered when a session is started between the user and the service - @Override +      Public voidsessioncreated (httpsessionevent httpsessionevent) { -HttpSession session=httpsessionevent.getsession (); +ServletContext application=Session.getservletcontext (); A         //Get SessionID atString sessionid=Session.getid (); -         //If this is a new session -         if(Session.isnew ()) { -String user= (String) Session.getattribute ("User"); -             //user not logged in as guest handling -User= (user==NULL)?"Visitors": User; inMap<string,string> online= (map<string, string>) Application.getattribute ("Online"); -             if(online==NULL){ toOnline=NewHashtable<string,string>(); +                 //put the user's online information in a map - Online.put (sessionid,user); theApplication.setattribute ("Online", online); *             } $         }Panax Notoginseng     } -  the     //This method is triggered when the session disconnects between the user and the server + @Override A      Public voidsessiondestroyed (httpsessionevent httpsessionevent) { theHttpSession session=httpsessionevent.getsession (); +ServletContext application=Session.getservletcontext (); -String sessionid=Session.getid (); $Map<string,string> online= (map<string,string>) Application.getattribute ("Online"); $         if(online!=NULL){ -             //Delete the user's online information - Online.remove (sessionId); the         } -Application.setattribute ("Online", online);Wuyi     } the}

"Java EE Enterprise Application Combat Learning record" Sessionlistener