Web app root system property already set to different value 异常的解决

异常内容如下：

2010-5-14 9:45:40 org.apache.catalina.core.StandardContext listenerStart
严重: Exception sending context initialized event to listener instance of class org.springframework.web.util.Log4jConfigListener
java.lang.IllegalStateException: Web app root system property already set to different value: 'webapp.root' = [F:\JDKandTOMCAT\TOMCAT\Tomcat 6.0\webapps\AVerPortal\] instead of [F:\JDKandTOMCAT\TOMCAT\Tomcat 6.0\webapps\AVerPortalTest\] - Choose unique values for the 'webAppRootKey' context-param in your web.xml files!

原因是两个Web应用的web.xml文件定义了相同的webAppRootKey，解决方法如下：

### app1:
<context-param>
    <param-name>webAppRootKey</param-name>
    <param-value>app1.root</param-value>
</context-param>

### app2:
<context-param>
    <param-name>webAppRootKey</param-name>
    <param-value>app2.root</param-value>
</context-param>