在java中测试访问连接是否可用解决办法

    public static boolean checkUrl(String url){        try {            HttpURLConnection con =                 (HttpURLConnection)new URL(url).openConnection();            int respCode = con.getResponseCode();            return respCode==404 ? false : true;            //return respCode!=200 ? false : true;        } catch (Exception e) {            e.printStackTrace();            return false;        }    }