根据图片url地址获取图片的宽高

      /**
      * 根据img获取图片的宽高
      * @param img 图片地址
      * @return  图片的对象，对象中图片的真实宽高
      */
     public  BufferedImage getBufferedImage(String imgurl) {
         URL url = null;
         InputStream is = null;
         BufferedImage img = null;
         try {
             url = new URL(imgurl);
             HttpURLConnection con =(HttpURLConnection)url.openConnection();
             //  设置请求头信息
             con.setRequestProperty("User-Agent", "Mozilla/5.0 (Windows NT 6.1; WOW64; rv:47.0) Gecko/20100101 Firefox/47.0");
             con.setRequestProperty("Accept", "text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8");
             con.setRequestProperty("Connection", "keep-alive");

             is = con.getInputStream();
             img = ImageIO.read(is);
         } catch (MalformedURLException e) {
             e.printStackTrace();
             log.error(e);
         } catch (Exception e) {
             img=null;
             log.error(e);
             e.printStackTrace();
         } finally {
             try {
                 if(is!=null){
                      is.close();
                 }
             } catch (IOException e) {
                 e.printStackTrace();
                 log.error(e);
             }
         }
         return img;
     }