通过url获取图片并保存至本地

   /**
     * 通过url获取图片并保存至本地
     */
    public  String getImgFromUrl(String urlstr) {
    	 String head_path = ConfigManager.get("head_path");
    	 String head_path_db = ConfigManager.get("head_path_db");
        int num = urlstr.indexOf('/',8);
        int extnum = urlstr.lastIndexOf('.');
        String u = urlstr.substring(0,num);
        String ext = urlstr.substring(extnum+1,urlstr.length());
        if(ext.equals("jpg") || ext.equals("jpeg") || ext.equals("jpe") || ext.equals("jfif") ||ext.equals("png") ||ext.equals("gif")){
        }else{
        	ext = "jpg";
        }
        try{
//            long curTime = System.currentTimeMillis();
//            Random random = new Random(100000000);
        	String uuid = UUID.randomUUID().toString().replace("-","");
        	// 图片的路径
        	String path = head_path + uuid + "." + ext;
        	//入库路径
        	String dataPath = head_path_db + uuid + "." + ext;
//            String fileName = String.valueOf(curTime) + "_"
//                    + random.nextInt(100000000) + ext;
            URL url = new URL(urlstr);
            URLConnection connection = url.openConnection();
            connection.setDoOutput(true);
            connection.setRequestProperty("referer", u);       
            //通过这个http头的伪装来反盗链
            BufferedImage image = ImageIO.read(connection.getInputStream());
            FileOutputStream fout=new FileOutputStream(path);
            if("gif".equals(ext)|| "png".equals(ext))
            {
                 ImageIO.write(image, ext, fout);
            }
            ImageIO.write(image, "jpg", fout);
            fout.flush();
            fout.close();
                   
            return dataPath;
        }       
        catch(Exception e)
        {
            System.out.print(e.getMessage().toString());
        }
        return "";
    }