Server Tomcat v8.5 Server at localhost failed to start

在学Struts2时，遇到Tomcat报错：Server Tomcat v8.5 Server at localhost failed to start.

console台部分报错信息：

Caused by: org.apache.catalina.LifecycleException: Failed to start component [StandardEngine[Catalina].StandardHost[localhost].StandardContext[/struts2Helloworld2]]
    at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:167)
    ... 6 more
Caused by: java.lang.IllegalArgumentException: Filter mapping specifies an unknown filter name [struts2]

错误原因：

web.xml中<filter>和<filter-mapping>中的filter-name不一致。

解决方法：

把<filter>和<filter-mapping>中的filter-name改为一致就好了。