url转换为InputStream流

public static InputStream urlToInputStream(String linkUrl) throws IOException {
        try {
            URL url = new URL(linkUrl);
            HttpURLConnection conn = (HttpURLConnection) url.openConnection();
            conn.setRequestMethod("GET");
            conn.setConnectTimeout(15 * 1000);
            conn.setRequestProperty("User-Agent", "Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/63.0.3239.84 Safari/537.36");
            conn.connect();
            return conn.getInputStream();
        }
        catch(Exception e){
            e.printStackTrace();
            return null;
        }
    }