<context-param>

        <param-name>webAppRootKey</param-name>

        <param-value>xxxxx.root</param-value>

    </context-param>

public static void setWebAppRootSystemProperty(ServletContext servletContext) throws IllegalStateException {

        Assert.notNull(servletContext, "ServletContext must not be null");

        String root = servletContext.getRealPath("/");

        if (root == null) {

            throw new IllegalStateException(

                "Cannot set web app root system property when WAR file is not expanded");

        }

        String param = servletContext.getInitParameter(WEB_APP_ROOT_KEY_PARAM);

        String key = (param != null ? param : DEFAULT_WEB_APP_ROOT_KEY);

        String oldValue = System.getProperty(key);

        if (oldValue != null && !StringUtils.pathEquals(oldValue, root)) {

            throw new IllegalStateException(

                "Web app root system property already set to different value: '" +

                key + "' = [" + oldValue + "] instead of [" + root + "] - " +

                "Choose unique values for the 'webAppRootKey' context-param in your web.xml files!");

        }

        System.setProperty(key, root);

        servletContext.log("Set web app root system property: '" + key + "' = [" + root + "]");

    }