在docker安装tomcat的时候，报错：Caused by: java.lang.IllegalArgumentException: The AJP Connector is configured with secretRequired="true

　　初识docker，试着在docker中安装tomcat（安装的tomcat8.5），并且挂载到宿主机的相关目录下，结果启动的时候报错：

12-May-2020 01:14:34.061 SEVERE [main] org.apache.catalina.core.StandardService.startInternal Failed to start connector [Connector[AJP/1.3-8009]]
	org.apache.catalina.LifecycleException: Protocol handler start failed
		at org.apache.catalina.connector.Connector.startInternal(Connector.java:1085)
		at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:183)
		at org.apache.catalina.core.StandardService.startInternal(StandardService.java:440)
		at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:183)
		at org.apache.catalina.core.StandardServer.startInternal(StandardServer.java:766)
		at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:183)
		at org.apache.catalina.startup.Catalina.start(Catalina.java:688)
		at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
		at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
		at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
		at java.lang.reflect.Method.invoke(Method.java:498)
		at org.apache.catalina.startup.Bootstrap.start(Bootstrap.java:343)
		at org.apache.catalina.startup.Bootstrap.main(Bootstrap.java:474)
	Caused by: java.lang.IllegalArgumentException: The AJP Connector is configured with secretRequired="true" but the secret attribute is either null or "". This combination is not valid.
		at org.apache.coyote.ajp.AbstractAjpProtocol.start(AbstractAjpProtocol.java:274)
		at org.apache.catalina.connector.Connector.startInternal(Connector.java:1083)
		... 12 more
22-May-2020 01:14:34.062 INFO [main] org.apache.catalina.startup.Catalina.start Server startup in 124 ms

　　查阅资料，发现了8.5版本的tomcat的sever.xml中有个属性 secretRequired需要给设置值：

<Connector port="8009" protocol="AJP/1.3" redirectPort="8443" />

设置成""就可以了，也就是下面的设置结果：

<Connector port="8009" protocol="AJP/1.3" redirectPort="8443" secretRequired="" />

　　然后重新启动docer中的tomcat，发现启动成功了，大功告成！