java实现统一账户同一时间只能在一个地方登陆

现在所做的手机软件要求类似QQ,当一处登陆.另外一处就要取消.所以查看了一下源代码.发现代码实现如下

web.xml:实现监听session作用.一旦session出现登陆、重复登录或者超时等.调用session中的方法

	<!-- session管理监听 -->
	<listener>
		<listener-class>com.yitong.app.listener.SessionManageListener</listener-class>
	</listener>

	<!-- session超时定义,单位为分钟 -->
	<session-config>
		<session-timeout>15</session-timeout>
	</session-config>

session类:继承自javax.servlet.http.HttpSessionListener接口,并且实现了该接口内的sessionCreated()和sessionDestroyed()两个方法,sessionCreated方法获取了从

HttpSessionListener中获取的session并创建实例.sessionDestroyed()方法负责获取session中超时或者异常状态的session加以销毁

package com.yitong.app.listener;

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

import org.apache.log4j.Logger;

import com.yitong.app.communicate.bean.SessionInstance;

/**
 * session管理监听类
 * 
 * @author twf
 * 
 */
public class SessionManageListener implements HttpSessionListener {
	private Logger logger = Logger.getLogger(this.getClass());

	@Override
	public void sessionCreated(HttpSessionEvent event) {
		HttpSession session = event.getSession();//session监听类接收到的
		logger.debug("Web 容器Session对象被创建,sid:" + session.getId());
	}

	@Override
	public void sessionDestroyed(HttpSessionEvent event) {
		try {

			HttpSession session = event.getSession();
			logger.debug("有session被销毁=" + session.getId());
			
			SessionInstance instance = SessionInstance.getSessionInstance();
			if(instance.hasSessionById(session.getId())){
				
				instance.removeSessionId(session.getId());
			}
			
			// 关闭过期连接
//			HttpMsgClient.cm.closeExpiredConnections();
		} catch (Exception e) {
			logger.error("清理session 实例失败", e);
		}
	}
}