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

由于系統架構需要同時啟動多個web項目，開發時每個項目用不同的tomcat啟動，沒有任何問題，等到釋出時放在同一個tomcat中時出現異常資訊，分析原因如下：

當在tomcat的server.xml中部署多個web應用時，出現這種異常：

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)

解決辦法：

打開web應用中的web.xml檔案，檢視

并檢查兩個應用中的webAppRootKey是否定義了相同的值