使用ehache进行缓存，可以再登陆认证成功后缓存认证授权及权限信息，但是用户退出时，该用户对应的权限信息不能进行实时更新，所以要求在用户退出系统时可以清理其对应的权限信息缓存。
在配置ehcache缓存是我们配置了myshiroCache，并在myrealm中指定了权限缓存的名字，所以在用户退出时就可以通过cacheManager及缓存名字获取该信息，并清理，实现退出系统时清理权限信息。
package com.copsec.railway.im.util;import org.apache.log4j.Logger;import org.apache.shiro.SecurityUtils;import org.apache.shiro.cache.Cache;import org.apache.shiro.cache.CacheManager;import org.apache.shiro.subject.SimplePrincipalCollection;import org.apache.shiro.subject.Subject;public class ShiroAuthorizationHelper { ???private static CacheManager cacheManager; ???private static Logger logger = Logger.getLogger(ShiroAuthorizationHelper.class); ???/** ????* 清除用户的权限 ????* ?????* ????* @param principal 登陆用户对应的principal对象 ????*/ ???public static void clearAuthorizationInfo(SimplePrincipalCollection principal) { ???????logger.info("clear the user: " + principal.toString() + "‘s authorizationInfo"); ???????Cache<Object, Object> cache = cacheManager.getCache("myShiroCache"); ???????cache.remove(principal); ???} ???/** ????* 清除当前用户的权限 ????*/ ???public static void clearAuthorizationInfo() { ???????if (SecurityUtils.getSubject().isAuthenticated()) { ???????????Subject subject = SecurityUtils.getSubject(); ???????????String username = subject.getPrincipal().toString(); ???????????String realmName = subject.getPrincipals().getRealmNames().iterator().next(); ???????????SimplePrincipalCollection principalCollection = new SimplePrincipalCollection(username, realmName); ???????????logger.debug("get user principalCollection :"+principalCollection); ???????????// 调用清理用户权限 ???????????clearAuthorizationInfo(principalCollection); ???????} ???} ???/** ????* 由Spring bean将对象注入 ????* @param cacheManager ????*/ ???public static void setCacheManager(CacheManager cacheManager) { ???????????????ShiroAuthorizationHelper.cacheManager = cacheManager; ???}}完成后即可在logout controller中调用，进行清理权限信息。
SSM+Apache shiro--ehcache缓存清理
原文地址：https://www.cnblogs.com/adam1991/p/8283991.html