Java Web Error:choose unique values for the ' Webapprootkey '

Two apps were deployed using Tomcat, and it was found that there was always a default boot not up. A discovery was made from the Tomcat log.

Log information:

April 19, 2016 9:09:55 am Org.apache.catalina.core.StandardContext listenerstart
Severe:exception sending context initialized event to listener instance of class Ch.qos.logback.ext.spring.web.LogbackCo Nfiglistener
Java.lang.IllegalStateException:Web App root system property already set to different value: ' Webapp.root ' = [D:\Program Files (x86) \apache software Foundation\tomcat 7.0\webapps\AppA\] Instead of [D:\Program Files (x86) \apache software Foundation\tomcat 7.0\webapps\AppB\]-Choose unique values for the ' Webapprootkey ' Context-param in your web. XML files!
At Org.springframework.web.util.WebUtils.setWebAppRootSystemProperty (webutils.java:148)
At ch.qos.logback.ext.spring.web.WebLogbackConfigurer.initLogging (Unknown Source)
At ch.qos.logback.ext.spring.web.LogbackConfigListener.contextInitialized (Unknown Source)
At Org.apache.catalina.core.StandardContext.listenerStart (standardcontext.java:4973)
At Org.apache.catalina.core.StandardContext.startInternal (standardcontext.java:5467)
At Org.apache.catalina.util.LifecycleBase.start (lifecyclebase.java:150)
At Org.apache.catalina.core.ContainerBase.addChildInternal (containerbase.java:901)
At Org.apache.catalina.core.ContainerBase.addChild (containerbase.java:877)
At Org.apache.catalina.core.StandardHost.addChild (standardhost.java:632)
At Org.apache.catalina.startup.HostConfig.deployDirectory (hostconfig.java:1229)
At Org.apache.catalina.startup.hostconfig$deploydirectory.run (hostconfig.java:1875)
At Java.util.concurrent.executors$runnableadapter.call (Unknown Source)
At Java.util.concurrent.futuretask$sync.innerrun (Unknown Source)
At Java.util.concurrent.FutureTask.run (Unknown Source)
At Java.util.concurrent.ThreadPoolExecutor.runWorker (Unknown Source)
At Java.util.concurrent.threadpoolexecutor$worker.run (Unknown Source)
At Java.lang.Thread.run (Unknown Source)

Search the online colleague's solution:

Modify Web. xml to use different Webapprootkey values for two apps. Restart app discovery apps are up.

<context-param>
<param-name>webAppRootKey</param-name>
<param-value>webName.root</param-value>
</context-param>

Java Web Error:choose unique values for the ' Webapprootkey '