Java根据sessionId获取Session对象

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1. 建立一个自己的SessionContext：

程序代码：

package cn.org.jshuwei.session.core;

import javax.servlet.http.HttpSession;
import java.util.HashMap;

public class MySessionContext {
    private static MySessionContext instance;
     private HashMap mymap;
}
     private MySessionContext() {
       mymap = new HashMap();
     }

     public static MySessionContext getInstance() {
        if (instance == null) {
             instance = new MySessionContext();
        }
        return instance;
    }

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

    public synchronized void DelSession(HttpSession session) {
        if (session != null) {
            mymap.remove(session.getId());
        }
    }

    public synchronized HttpSession getSession(String session_id) {
        if (session_id == null) return null;
         return (HttpSession) mymap.get(session_id);
    }

}

2.新建一个Session监听

程序代码

package cn.org.jshuwei.session.core;

import javax.servlet.http.HttpSessionListener;
import javax.servlet.http.HttpSessionEvent;
import javax.servlet.http.HttpSession;
import java.util.HashMap;
import java.util.Map;

public class SessionListener implements HttpSessionListener {
public static Map userMap = new HashMap();
     private MySessionContext myc=MySessionContext.getInstance();

    public void sessionCreated(HttpSessionEvent httpSessionEvent) {
         myc.AddSession(httpSessionEvent.getSession());
    }

    public void sessionDestroyed(HttpSessionEvent httpSessionEvent) {
        HttpSession session = httpSessionEvent.getSession();
        myc.DelSession(session);
     }
}
3.在web.xml中配置

程序代码

<listener>
<listener-class>cn.org.jshuwei.session.core.SessionListener</listener-class>
</listener>

4.使用

程序代码

MySessionContext myc= MySessionContext.getInstance();
HttpSession sess = myc.getSession(sessionId);