关闭tomcat时或者重启tomcat时 log4j2 报错： sun.misc.Unsafe.park(Native Method)
异常信息：
30-Aug-2018 15:59:34.900 SEVERE [localhost-startStop-2] org.apache.catalina.loader.WebappClassLoader.clearReferencesThreads The web application [] appears to have started a thread named [Thread-14] but has failed to stop it. This is very likely to create a memory leak. 30-Aug-2018 15:59:34.901 SEVERE [localhost-startStop-2] org.apache.catalina.loader.WebappClassLoader.clearReferencesThreads Stack trace of thread "Thread-14": sun.misc.Unsafe.park(Native Method) java.util.concurrent.locks.LockSupport.parkNanos(LockSupport.java:215) java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject.awaitNanos(AbstractQueuedSynchronizer.java:2078) java.util.concurrent.ScheduledThreadPoolExecutor$DelayedWorkQueue.take(ScheduledThreadPoolExecutor.java:1093) java.util.concurrent.ScheduledThreadPoolExecutor$DelayedWorkQueue.take(ScheduledThreadPoolExecutor.java:809) java.util.concurrent.ThreadPoolExecutor.getTask(ThreadPoolExecutor.java:1074) java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1134) java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624) java.lang.Thread.run(Thread.java:748)
新项目使用log4j2+springmvc的方式，但是报这个错，查了很多资料，原因是log4j2-2.6开始引入shutdown()，在2.6中，如果web app卸载时没有进行shutdown()，tomcat会发布内存泄漏风险的告警。
在web.xml里加入下边代码块，要放在spring相关配置前边
<listener> <listener-class>org.apache.logging.log4j.web.Log4jServletContextListener</listener-class> </listener> <context-param> <param-name>isLog4jAutoInitializationDisabled</param-name> <param-value>true</param-value> </context-param>