一、背景
当我们使用了nginx做项目集群以后，就会出现一个很严重的问题亟待解决，那就是：tomcat集群之间如何实现session共享的问题，如果这个问题不解决，就会出现登陆过后再次请求资源依旧需要登陆的问题。这篇文章我们就解决这个问题。
二、实现步骤
说明：本篇是在spring+shiro集成的基础上进行改进的，如果不知道spring和shiro怎么集成，请移步：spring集成shiro做登陆认证
1.在pom.xml中添加shiro-redis和jedis的依赖
<dependency>
<groupId>org.crazycake</groupId>
<artifactId>shiro-redis</artifactId>
<version>2.4.2.1-RELEASE</version>
</dependency>
<dependency>
<groupId>redis.clients</groupId>
<artifactId>jedis</artifactId>
<version>2.7.2</version>
</dependency>
2.首先我们需要对redis进行集成，在resources下新建config.properties
#redis pool config
redis.pool.maxActive=200
redis.pool.maxIdle=100
redis.pool.maxWait=100
redis.pool.testOnBorrow=true
#redis config
redis.host=192.168.85.129
redis.port=6379
redis.timeout=2000
redis.password=123456
redis.dbindex=8
redis.default.expire=1800000
3.在resources/spring文件夹下新建spring-redis.xml来集成redis操作客户端
<?xml version="1.0" encoding="UTF-8"?> <beans xmlns="http://www.springframework.org/schema/beans" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd"> <description>Redis configuration</description> <bean id="redisPoolConfig" class="redis.clients.jedis.JedisPoolConfig"> <property name="maxTotal" value="${redis.pool.maxActive}"/> <property name="maxIdle" value="${redis.pool.maxIdle}"/> <property name="maxWaitMillis" value="${redis.pool.maxWait}"/> <property name="testOnBorrow" value="${redis.pool.testOnBorrow}"/> </bean> <bean id="jedisPool" class="redis.clients.jedis.JedisPool" destroy-method="destroy"> <constructor-arg ref="redisPoolConfig"/> <constructor-arg value="${redis.host}"/> <constructor-arg type="int" value="${redis.port}"/> <constructor-arg type="int" value="${redis.timeout}"/> <constructor-arg type="java.lang.String" value="${redis.password}"/> <constructor-arg type="int" value="${redis.dbindex}"/> </bean> <bean id="redisClient" class="com.hafiz.www.redis.RedisClient"> <constructor-arg name="jedisPool" ref="jedisPool"/> <property name="expire" value="${redis.default.expire}"/> </bean> </beans>
4.添加redisClient.java作为访问redis的客户端
package com.hafiz.www.redis; import org.crazycake.shiro.RedisManager; import org.slf4j.Logger; import org.slf4j.LoggerFactory; import redis.clients.jedis.Jedis; import redis.clients.jedis.JedisPool; import java.util.Set; /** * Desc: Jedis 操作客户端 * Created by hafiz.zhang on 2017/7/21. */ public class RedisClient extends RedisManager{ private static final Logger LOGGER = LoggerFactory.getLogger(RedisClient.class); private static JedisPool jedisPool = null; public RedisClient(JedisPool jedisPool) { this.jedisPool = jedisPool; } public void init() { super.init(); } @Override public byte[] get(byte[] key) { Jedis jedis = jedisPool.getResource(); byte[] value; try { value = jedis.get(key); } catch (Exception e) { LOGGER.error("redis key:{} get value occur exception", new String(key)); throw new RuntimeException("redis operation error:", e); } finally { jedis.close(); } return value; } @Override public byte[] set(byte[] key, byte[] value) { Jedis jedis = jedisPool.getResource(); try { jedis.set(key, value); Integer expire = getExpire(); if(expire != 0) { jedis.expire(key, expire); } } catch (Exception e) { LOGGER.error("redis key:{} set value:{} occur exception", new String(key), new String(value)); throw new RuntimeException("redis operation error:", e); } finally { jedis.close(); } return value; } @Override public byte[] set(byte[] key, byte[] value, int expire) { Jedis jedis = jedisPool.getResource(); try { jedis.set(key, value); if(expire != 0) { jedis.expire(key, expire); } } catch (Exception e) { LOGGER.error("redis key:{} set value:{} in expire:{} occur exception", new String(key), new String(value), expire); throw new RuntimeException("redis operation error:", e); } finally { jedis.close(); } return value; } @Override public void del(byte[] key) { Jedis jedis = jedisPool.getResource(); try { jedis.del(key); } catch (Exception e) { LOGGER.error("redis key:{} del value occur exception", new String(key)); throw new RuntimeException("redis operation error:", e); } finally { jedis.close(); } } @Override public void flushDB() { Jedis jedis = jedisPool.getResource(); try { jedis.flushDB(); } catch (Exception e) { LOGGER.error("redis flushDB occur exception"); throw new RuntimeException("redis operation error:", e); } finally { jedis.close(); } } @Override public Long dbSize() { Long dbSize = Long.valueOf(0L); Jedis jedis = jedisPool.getResource(); try { dbSize = jedis.dbSize(); } catch (Exception e) { LOGGER.error("redis get dbSize occur exception"); throw new RuntimeException("redis operation error:", e); } finally { jedis.close(); } return dbSize; } @Override public Set<byte[]> keys(String pattern) { Set keys = null; Jedis jedis = jedisPool.getResource(); try { keys = jedis.keys(pattern.getBytes()); } catch (Exception e) { LOGGER.error("redis get keys in pattern:{} occur exception", pattern); throw new RuntimeException("redis operation error:", e); } finally { jedis.close(); } return keys; } }
5.接着，我们对spring-shiro.xml做如下修改(红色标记的部分)
<?xml version="1.0" encoding="UTF-8"?> <beans xmlns="http://www.springframework.org/schema/beans" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:util="http://www.springframework.org/schema/util" xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd http://www.springframework.org/schema/util http://www.springframework.org/schema/util/spring-util.xsd"> <description>Shiro Configuration</description> <!--shiro-redis redisCacheManager--> <bean id="redisCacheManager" class="org.crazycake.shiro.RedisCacheManager"> <property name="keyPrefix" value="shiro_redis_session:"/> <property name="redisManager" ref="redisClient"/> </bean> <!--custom myself realm--> <bean id="customRealm" class="com.hafiz.www.shiro.CustomRealm"> <property name="cacheManager" ref="redisCacheManager"/> </bean> <!--redisSessionDAO--> <bean id="redisSessionDAO" class="org.apache.shiro.session.mgt.eis.EnterpriseCacheSessionDAO"></bean> <!--simpleCookie,不定义在集群环境下会出现There is no session with id ....--> <bean id="simpleCookie" class="org.apache.shiro.web.servlet.SimpleCookie"> <constructor-arg name="name" value="custom.session"/> <property name="path" value="/"/> </bean> <!--sessionManager--> <bean id="sessionManager" class="org.apache.shiro.web.session.mgt.DefaultWebSessionManager"> <property name="sessionDAO" ref="redisSessionDAO"/> <property name="sessionIdCookie" ref="simpleCookie"/> </bean> <!--Shiro`s main business-tier object for web-enable applications--> <bean id="securityManager" class="org.apache.shiro.web.mgt.DefaultWebSecurityManager"> <property name="realm" ref="customRealm"/> <property name="cacheManager" ref="redisCacheManager"/> <property name="sessionManager" ref="sessionManager"/> </bean> <!--shiro filter--> <bean id="shiroFilter" class="org.apache.shiro.spring.web.ShiroFilterFactoryBean"> <property name="securityManager" ref="securityManager"/> <property name="loginUrl" value="/login.html"/> <property name="successUrl" value="/index.html"/> <property name="unauthorizedUrl" value="/unauthorized.html"/> <property name="filters"> <util:map> <entry key="auth"> <bean class="com.hafiz.www.filter.AuthorizeFilter"/> </entry> </util:map> </property> <property name="filterChainDefinitions"> <value> /login.json = anon /logout.json = anon /js/** = anon / = authc /** = auth </value> </property> </bean> </beans>
6.spring.xml做如下修改
<?xml version="1.0" encoding="UTF-8"?> <beans xmlns="http://www.springframework.org/schema/beans" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:context="http://www.springframework.org/schema/context" xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context.xsd"> <context:property-placeholder location="classpath:config.properties,classpath:jdbc.properties"/> <import resource="spring-*.xml"/> </beans>
到此我们就完了shiro+redis实现session共享的问题，其实也很简单，其中的实现逻辑也很简单，就是shiro的拦截器会首先去redis里面获取session,作为当本次请求的session.
其他代码以及简单测试代码不再贴出，给出github地址：https://github.com/hafizzhang/shiro-session-cluster.git
三、总结
通过本文，我们就完成了spring+shiro+redis实现集群session共享的问题，经过亲测可行。但有一点遗憾的地方，就是每次请求至少会有8次redis的读操作，一次写操作，这个问题还没有找到很好的解决办法，本地使用ehcahe也不太现实，因为涉及到本地缓存和redis缓存同步的问题，如果你有好的办法，欢迎讨论交流学习！
