Tomcat报错

java.util.concurrent.ExecutionException: java.lang.NullPointerExceptionat java.util.concurrent.FutureTask.report(Unknown Source)at java.util.concurrent.FutureTask.get(Unknown Source)at org.apache.catalina.startup.HostConfig.deployDirectories(HostConfig.java:1022)at org.apache.catalina.startup.HostConfig.deployApps(HostConfig.java:473)at org.apache.catalina.startup.HostConfig.check(HostConfig.java:1457)at org.apache.catalina.startup.HostConfig.lifecycleEvent(HostConfig.java:295)at org.apache.catalina.util.LifecycleSupport.fireLifecycleEvent(LifecycleSupport.java:119)at org.apache.catalina.util.LifecycleBase.fireLifecycleEvent(LifecycleBase.java:90)at org.apache.catalina.core.ContainerBase.backgroundProcess(ContainerBase.java:1379)at org.apache.catalina.core.ContainerBase$ContainerBackgroundProcessor.processChildren(ContainerBase.java:1537)at org.apache.catalina.core.ContainerBase$ContainerBackgroundProcessor.processChildren(ContainerBase.java:1547)at org.apache.catalina.core.ContainerBase$ContainerBackgroundProcessor.run(ContainerBase.java:1526)at java.lang.Thread.run(Unknown Source)Caused by: java.lang.NullPointerExceptionat org.apache.catalina.startup.HostConfig.addWatchedResources(HostConfig.java:1157)at org.apache.catalina.startup.HostConfig.deployDirectory(HostConfig.java:1118)at org.apache.catalina.startup.HostConfig$DeployDirectory.run(HostConfig.java:1621)at java.util.concurrent.Executors$RunnableAdapter.call(Unknown Source)at java.util.concurrent.FutureTask.run(Unknown Source)at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)... 1 more

在Tomcat启动时遇到这个问题：最后发现在写context.xml配置文件时，把<Context>写成了小写的<context>

这种问题有时候比较难发现

总结下我查这个错误的过程

1，把所以得tomcat中的所以项目全部移除掉，发现正常启动，

2，在项目部署下，启动服务器，还是会报错，说明是项目中的哪个配置文件写错了，

3，把tomcat中的所有的配置文件内容注释掉，启动，还是会报错，

4，打开注释，把context.xml文件删除，正常启动了。

5，再重点看了下context.xml配置文件的各个标签，发现问题了。于是解决了。