单用户登陆、在线用户统计Java

登陆成功代码：

MySession.getInstance().deleteSession(user.getPhone(),session);

MySession.getInstance().addSessionIdToPhone(session, user.getPhone());

WEB：配置

 <listener>  

           <listener-class>cn.yitongworld.utils.SessionListener</listener-class>  

  </listener> 

package cn.yitongworld.utils;

import javax.servlet.http.HttpSessionEvent;
import javax.servlet.http.HttpSessionListener;


public class SessionListener implements HttpSessionListener{

@Override
public void sessionCreated(HttpSessionEvent event) {
MySession.getInstance().addSession(event.getSession());
}


@Override
public void sessionDestroyed(HttpSessionEvent event) {
MySession.getInstance().deleteSession(event.getSession());
}

}

package cn.yitongworld.utils;
import java.util.HashMap;
import java.util.Map;
import javax.servlet.http.HttpSession;


public class MySession {
private static MySession instance = new MySession();
private static Map<String, HttpSession> sessionMap = new HashMap<String, HttpSession>();
private static Map<String, String> sessionIdToPhone = new HashMap<String, String>();
private static Map<String, String> phoneToSessionId = new HashMap<String, String>();


private MySession() {
}


public static MySession getInstance() {
return instance;
}


public synchronized void addSession(HttpSession session) {
if (session != null) {
sessionMap.put(session.getId(), session);
}
}


public synchronized void deleteSession(HttpSession session) {
if (session != null) {
sessionMap.remove(session.getId());
phoneToSessionId.remove(sessionIdToPhone.get(session.getId()));
sessionIdToPhone.remove(session.getId());
}
}


public synchronized void addSessionIdToPhone(HttpSession session,
String phone) {
if (session != null) {
sessionIdToPhone.put(session.getId(), phone);
phoneToSessionId.put(phone, session.getId());
}
}


public synchronized void deleteSession(String phone, HttpSession session) {
String sessionId = phoneToSessionId.get(phone);
sessionIdToPhone.remove(sessionId);
phoneToSessionId.remove(phone);
HttpSession session2 = sessionMap.get(sessionId);
if (session2 != null && !session2.getId().equals(session.getId())) {
session2.invalidate();
sessionMap.remove(session2.getId());
}
}


public synchronized void lginOut(String phone) {
String sessionId = phoneToSessionId.get(phone);
sessionIdToPhone.remove(sessionId);
phoneToSessionId.remove(phone);
HttpSession session = sessionMap.get(sessionId);
if (session != null) {
session.invalidate();
sessionMap.remove(session.getId());
}
}
public static HttpSession getSessionByPhone(String phone){
try{
String sessionId = phoneToSessionId.get(phone);
return sessionMap.get(sessionId);
}catch(Exception e){
e.printStackTrace();
return null;
}
}
}