java web工程中获取webroot 路径

在web.xml中加入

<context-param>    <param-name>webAppRootKey</param-name>    <param-value>           ebop-server.root       </param-value></context-param><listener>    <listener>        <listener-class>org.springframework.web.util.WebAppRootListener</listener-class>    </listener>//代码获取  String webroot = System.getProperty("ebop-server.root")