tomcat关闭时遇到的关于shiro警告

[路漫漫其修远兮 ,吾将上下而求索]

我的tomcat是8.0，框架中整合了shiro，在关闭tomcat时，会发出以下警告：
18-Jul-2018 18:40:45.453 SEVERE [localhost-startStop-2] org.apache.catalina.loader.WebappClassLoaderBase.checkThreadLocalMapForLeaks The web application [PT] created a ThreadLocal with key of type [org.apache.shiro.util.ThreadContext.InheritableThreadLocalMap] (value [org.apache.shiro.util.ThreadContext$InheritableThreadLocalMap@36ef9661]) and a value of type [java.util.HashMap] (value [{org.apache.shiro.util.ThreadContext_SECURITY_MANAGER_KEY=org.apache.shiro.web.mgt.DefaultWebSecurityManager@202bf094, org.apache.shiro.util.ThreadContext_SUBJECT_KEY=org.apache.shiro.web.subject.support.WebDelegatingSubject@21655b6b}]) but failed to remove it when the web application was stopped. Threads are going to be renewed over time to try and avoid a probable memory leak.

各位大大有什么好的解决办法吗？

[幽饮烛]

忽略这个警告吧，这个警告是因为用了 ThreadLocal，却没有手动清理才出现的。