java.lang.IllegalStateException: Web app root system property already set to different value:

由于系统架构需要同时启动多个web项目，开发时每个项目用不同的tomcat启动，没有任何问题，等到发布时放在同一个tomcat中时出现异常信息，分析原因如下：

当在tomcat的server.xml中部署多个web应用时，出现这种异常：

java.lang.IllegalStateException: Web app root system property already set to different value: 'abc' = [F:\workspace_mfms\platform\WebContent\] instead of [F:\workspace_mfms\mfms\WebContent\] - Choose unique values for the 'webAppRootKey' context-param in
your web.xml files!
at org.springframework.web.util.WebUtils.setWebAppRootSystemProperty(WebUtils.java:148)
at org.springframework.web.util.Log4jWebConfigurer.initLogging(Log4jWebConfigurer.java:117)
at org.springframework.web.util.Log4jConfigListener.contextInitialized(Log4jConfigListener.java:45)
at org.apache.catalina.core.StandardContext.listenerStart(StandardContext.java:4887)
at org.apache.catalina.core.StandardContext.startInternal(StandardContext.java:5381)
at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:150)
at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1559)
at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1549)
at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:303)
at java.util.concurrent.FutureTask.run(FutureTask.java:138)
at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:886)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:908)
at java.lang.Thread.run(Thread.java:662)

解决办法：

打开web应用中的web.xml文件，查看



并检查两个应用中的webAppRootKey是否定义了相同的值