前端页面获取web根路径

        String basePath = request.getScheme() + "://" + request.getServerName();
        if (request.getServerPort() != 80) {
            basePath += ":" + request.getServerPort();
        }
        basePath += request.getContextPath();
        request.setAttribute("basePath", basePath);
        request.setAttribute("requestURI", request.getRequestURI());