java根据sessionId创建、删除session

在有些情况下可能需要根据sessionId来增删改session，这时候我们可以通过监听来实现。代码如下。

1、创建监听MySessionListener.java

public class MySessionListener {
    public void sessionCreated(HttpSessionEvent httpSessionEvent) {
        MySessionContext.AddSession(httpSessionEvent.getSession());
    }
    public void sessionDestroyed(HttpSessionEvent httpSessionEvent) {
        HttpSession session = httpSessionEvent.getSession();
        MySessionContext.DelSession(session);
    }
}

public class MySessionContext {
    private static HashMap mymap = new HashMap();
        public static synchronized void AddSession(HttpSession session) {
                if (session != null) {
                        mymap.put(session.getId(), session);
                     }
             }
         public static synchronized void DelSession(HttpSession session) {
                 if (session != null) {
                         mymap.remove(session.getId());
                     }
             }
         public static synchronized HttpSession getSession(String session_id) {
                if (session_id == null)
                     return null;
                 return (HttpSession) mymap.get(session_id);
             }
}

<listener>
    <listener-class>路径.MySessionListener</listener-class>
</listener>

这样就可以了

HttpSession session = MySessionContext.getSession(sessionId);