本文共 9422 字，大约阅读时间需要 31 分钟。

背景

• 项目采用阿里云负载均衡，基于cookie的会话保持。
• 没有实现集群间的session共享。
• 项目采用spring security 并且配置了session策略如下：

一个账户只对应一个session，也就是一个用户在不同浏览器登陆，后登陆的会导致前面登陆的session失效。

问题分析

集群环境下，导致maximumSessions的配置失效。并不能实现预期的目标。因为session没有共享。

解决思路

• 采用spring data redis session解决实现session共享，统一管理。

  但是由于项目集成了过多的开源框架，由于版本原因，很难整合到一起。并且项目测试已经接近尾声，因此没有采用。

• zookeeper监听用户session 方式，后登陆时操作对应节点，触发监听事件，使其先创建的session失效。

最终采用zookeeper监听session方式

具体代码

session上下文保持

package com.raymon.cloudq.util;import javax.servlet.http.HttpSession;import java.util.Map;import java.util.concurrent.ConcurrentHashMap;public class SessionContext {
       private static SessionContext instance;    private Map
   
     sessionMap;    private SessionContext() {        sessionMap = new ConcurrentHashMap
    
     ();    }    public synchronized static SessionContext getInstance() {        if (instance == null) {            instance = new SessionContext();        }        return instance;    }    public  void addSession(HttpSession session) {        if (session != null) {            sessionMap.put(session.getId(), session);        }    }    public  void delSession(HttpSession session) {        if (session != null) {            sessionMap.remove(session.getId());        }    }    public  void delSession(String sessionId) {         sessionMap.remove(sessionId);    }    public  HttpSession getSession(String sessionId) {        if (sessionId == null)            return null;        return sessionMap.get(sessionId);    }}
    
   

基于zookeeper的session控制接口

** * 由于session在集群中没有实现共享，一个账户只能对应一个session * 基于zookeeper监听的 来控制 */public interface ClusterSessionsCtrlService {
       /**     * 设置监听     */    void setMaximumSessionsListener();    /**     * 注册zookeeper sesssion数据     * 后登陆的用户会删除先登录的节点，触发监听，让先登陆的session失效     * @param empId     * @param httpSession     */    void registerZookeeperSession(Integer empId,HttpSession httpSession);    /**     * session超时，删除zookeeper注册数据     * @param sessionId     */    void deleteZookeeperSessionRegister(String sessionId);}

session控制接口实现类

package com.raymon.cloudq.service.impl;import com.raymon.cloudq.service.ClusterSessionsCtrlService;import com.raymon.cloudq.util.SessionContext;import org.apache.commons.lang.StringUtils;import org.apache.curator.RetryPolicy;import org.apache.curator.framework.CuratorFramework;import org.apache.curator.framework.CuratorFrameworkFactory;import org.apache.curator.framework.api.transaction.CuratorOp;import org.apache.curator.framework.api.transaction.CuratorTransactionResult;import org.apache.curator.framework.recipes.cache.PathChildrenCache;import org.apache.curator.framework.recipes.cache.PathChildrenCacheEvent;import org.apache.curator.framework.recipes.cache.PathChildrenCacheListener;import org.apache.curator.retry.ExponentialBackoffRetry;import org.apache.zookeeper.CreateMode;import org.apache.zookeeper.data.Stat;import org.slf4j.LoggerFactory;import org.springframework.beans.factory.InitializingBean;import org.springframework.beans.factory.annotation.Value;import org.springframework.stereotype.Service;import javax.servlet.http.HttpSession;import java.util.ArrayList;import java.util.Collection;import java.util.List;@Servicepublic class ClusterSessionsCtrlServiceImpl implements ClusterSessionsCtrlService, InitializingBean {    @Value(" ${zookeeperhostName}")    private String zookeeperConnectionString;    private static String sessionPath = "/session";    private static String sessionReaPath = "/sessionrea";    protected static org.slf4j.Logger logger = LoggerFactory.getLogger(ClusterSessionsCtrlServiceImpl.class);    private CuratorFramework client = null;    @Override    public void afterPropertiesSet() throws Exception {        setMaximumSessionsListener();    }    @Override    public void setMaximumSessionsListener() {        RetryPolicy retryPolicy = new ExponentialBackoffRetry(1000, 3);        client = CuratorFrameworkFactory.builder().connectString(zookeeperConnectionString)                .sessionTimeoutMs(8000).retryPolicy(retryPolicy).build();        client.start();        try {            Stat stat = client.checkExists().forPath(sessionPath);            if (stat == null) {                client.create().creatingParentsIfNeeded().withMode(CreateMode.PERSISTENT).forPath(sessionPath);            }            stat = client.checkExists().forPath(sessionReaPath);            if (stat == null) {                client.create().creatingParentsIfNeeded().withMode(CreateMode.PERSISTENT).forPath(sessionReaPath);            }        } catch (Exception e) {            e.printStackTrace();            logger.error("zookeeper创建/session失败，原因{}", e.toString());        }        PathChildrenCache cache = null;        try {            cache = new PathChildrenCache(client, sessionPath, true);            cache.start();        } catch (Exception e) {            e.printStackTrace();            logger.error(e.toString());        }        PathChildrenCacheListener cacheListener = new PathChildrenCacheListener() {            @Override            public void childEvent(CuratorFramework client, PathChildrenCacheEvent event) throws Exception {                logger.info("事件类型：" + event.getType());                if( event.getData()!=null){                    logger.info("节点数据：" + event.getData().getPath() + " = " + new String(event.getData().getData()));                }                if (event.getType().equals(PathChildrenCacheEvent.Type.CHILD_REMOVED)) {                    HttpSession httpSession = SessionContext.getInstance().getSession(new String(event.getData().getData()));                    if (httpSession == null) {                        return;                    }                    httpSession.invalidate();                }            }        };        cache.getListenable().addListener(cacheListener);    }    @Override    public void deleteZookeeperSessionRegister(String sessionId) {        try {            SessionContext.getInstance().delSession(sessionId);            String empId = null;            Stat stat = client.checkExists().forPath(sessionReaPath + "/" + sessionId);            if (stat != null) {                empId = new String(client.getData().forPath(sessionReaPath + "/" + sessionId));                client.delete().forPath(sessionReaPath + "/" + sessionId);                logger.info("delete session：" + sessionReaPath + "/" + sessionId);            }         /*   stat = client.checkExists().forPath(sessionPath + "/" + empId);            if (StringUtils.isNotEmpty(empId) && stat != null) {                client.delete().forPath(sessionPath + "/" + empId);                logger.info("delete session：" + sessionPath + "/" + empId);            }*/        } catch (Exception e) {            e.printStackTrace();            logger.error(e.toString());        }    }    @Override    public void registerZookeeperSession(Integer empId, HttpSession httpSession) {        try {            SessionContext.getInstance().addSession(httpSession);            Stat stat = client.checkExists().forPath(sessionPath + "/" + empId);            List
   
     operations = new ArrayList
    
     ();            if (stat != null) {                CuratorOp deleteOpt  = client.transactionOp().delete().forPath(sessionPath + "/" + empId);                operations.add(deleteOpt);            }            CuratorOp createSessionPathOpt = client.transactionOp().create().withMode(CreateMode.EPHEMERAL).forPath(sessionPath + "/" + empId, httpSession.getId().getBytes());            CuratorOp createSessionReaPathOpt = client.transactionOp().create().withMode(CreateMode.EPHEMERAL).forPath(sessionReaPath + "/" + httpSession.getId(), String.valueOf(empId).getBytes());            operations.add(createSessionPathOpt);            operations.add(createSessionReaPathOpt);            Collection
     
       results = client.transaction().forOperations(operations);            for (CuratorTransactionResult result : results) {                logger.info(result.getForPath() + " - " + result.getType());            }        } catch (Exception e) {            e.printStackTrace();            logger.error(e.toString());        }    }}
     
    
   

session监听

/** * session监听 *  * */public class SessionListener  implements HttpSessionListener,  HttpSessionAttributeListener{
       private SessionContext context = SessionContext.getInstance();    Logger log = LoggerFactory.getLogger(SessionListener.class);    @Override    public void attributeAdded(HttpSessionBindingEvent arg0) {    }    @Override    public void attributeRemoved(HttpSessionBindingEvent arg0) {    }    @Override    public void attributeReplaced(HttpSessionBindingEvent arg0) {    }    @Override    public void sessionCreated(HttpSessionEvent arg0) {        if(log.isDebugEnabled()) {            log.debug("创建session");        }    }    @Override    public void sessionDestroyed(HttpSessionEvent arg0) {        context.delSession(arg0.getSession());        ApplicationContext ctx = WebApplicationContextUtils.getRequiredWebApplicationContext(arg0.getSession().getServletContext());        ClusterSessionsCtrlService clusterSessionsCtrlService = ctx.getBean(ClusterSessionsCtrlService.class);        clusterSessionsCtrlService.deleteZookeeperSessionRegister(arg0.getSession().getId());    }}

用户登陆成功需要注册session监听

clusterSessionsCtrlService.registerZookeeperSession(empId,request.getSession());

转载地址：http://xdgxf.baihongyu.com/