需求：

当有二级域名或者通过前置机路由那么需要获取其访问的真实bathpath

实现：

protected String getBasePath(HttpServletRequest request) {	StringBuffer url = request.getRequestURL();	String basePath = url			.delete(url.length() - request.getRequestURI().length(),					url.length()).append("/").toString();	return basePath;}