但是，我們可以通過(guò)HttpSessionListener監(jiān)聽(tīng)器和全局靜態(tài)map自己實(shí)現(xiàn)一個(gè)SessionContext。

MySessionContext.java:

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);
    }
}

MySessionListener.java:

public class MySessionListener implements HttpSessionListener {
    public void sessionCreated(HttpSessionEvent httpSessionEvent) {
    MySessionContext.AddSession(httpSessionEvent.getSession());
    }

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

}

web.xml添加一個(gè)監(jiān)聽(tīng)器：

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

根據(jù)sessionId獲取Session對(duì)象：

String sessionId = request.getParameter("sessionId");

HttpSession session = MySessionContext.getSession(sessionId);