异常信息：
06-Dec-2017 12:04:34.521 警告 [localhost-startStop-1] org.apache.catalina.loader.WebappClassLoaderBase.clearReferencesThreads The web application [ROOT] appears to have started a thread named [Log4j2-TF-8-Scheduled-2] but has failed to stop it. This is very likely to create a memory leak. Stack trace of thread:
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$DelayedWorkQueue.take(ScheduledThreadPoolExecutor.java:809)
java.util.concurrent.ThreadPoolExecutor.getTask(ThreadPoolExecutor.java:1067)
java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1127)
java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
java.lang.Thread.run(Thread.java:745)
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。
解决方式是引入log4j2-web.jar，但是我这边引入后并没有解决，又google到处找方法，最后在一个同样出问题的帖子里找到了个方法可以解决
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>
