java 实现微信服务器下载图片到自己服务器

 public class PicDownload {        public static InputStream getInputStream(String accessToken, String mediaId) {     InputStream is = null;     String url = "https://cache.yisu.com/upload/information/20200623/121/114033");       while ((len = inputStream.read(data)) != -1) {         fileOutputStream.write(data, 0, len);       }     } catch (IOException e) {       e.printStackTrace();     } finally {       if (inputStream != null) {         try {           inputStream.close();         } catch (IOException e) {           e.printStackTrace();         }       }       if (fileOutputStream != null) {         try {           fileOutputStream.close();         } catch (IOException e) {           e.printStackTrace();         }       }     }   }       public static void getPic(String accessToken, String mediaId) {     String requestUrl = "http://file.api.weixin.qq.com/cgi-bin/media/get?access_token=ACCESS_TOKEN&media_id=MEDIA_ID";     requestUrl = requestUrl.replace("ACCESS_TOKEN", accessToken).replace(         "MEDIA_ID", mediaId);     JSONObject jsonObject = WeixinUtil.httpRequest(requestUrl, "GET", null);     System.out.println(jsonObject);   }    public static void main(String[] args) throws Exception {     String accessToken = "";     String mediaId = "";     String picName = "";     saveImageToDisk(accessToken, mediaId, picName,"f:/");   } }