tomcat服务开不起来了（无法变成绿色）
stdout.log中提示：
Bootstrap: Class loader creation threw exception
java.lang.NoClassDefFoundError: org/apache/commons/logging/LogFactory
at org.apache.tomcat.util.compat.JdkCompat.<clinit>(JdkCompat.java:55)
at org.apache.catalina.startup.ClassLoaderFactory.<clinit>(ClassLoaderFactory.java:63)
at org.apache.catalina.startup.Bootstrap.initClassLoaders(Bootstrap.java:103)
at org.apache.catalina.startup.Bootstrap.init(Bootstrap.java:196)
at org.apache.catalina.startup.Bootstrap.main(Bootstrap.java:402)