java 实现微信服务器下载图片到自己服务器

/**  * @author why  *  */ public class PicDownload {    /**    *    * 根据文件id下载文件    *    *    *    * @param mediaId    *    *      媒体id    *    * @throws Exception    */    public static InputStream getInputStream(String accessToken, String mediaId) {     InputStream is = null;     String url = "http://file.api.weixin.qq.com/cgi-bin/media/get?access_token="         + accessToken + "&media_id=" + mediaId;     try {       URL urlGet = new URL(url);       HttpURLConnection http = (HttpURLConnection) urlGet           .openConnection();       http.setRequestMethod("GET"); // 必须是get方式请求       http.setRequestProperty("Content-Type",           "application/x-www-form-urlencoded");       http.setDoOutput(true);       http.setDoInput(true);       System.setProperty("sun.net.client.defaultConnectTimeout", "30000");// 连接超时30秒       System.setProperty("sun.net.client.defaultReadTimeout", "30000"); // 读取超时30秒       http.connect();       // 获取文件转化为byte流       is = http.getInputStream();      } catch (Exception e) {       e.printStackTrace();     }     return is;    }    /**    *    * 获取下载图片信息（jpg）    *    *    *    * @param mediaId    *    *      文件的id    *    * @throws Exception    */    public static void saveImageToDisk(String accessToken, String mediaId, String picName, String picPath)       throws Exception {     InputStream inputStream = getInputStream(accessToken, mediaId);     byte[] data = new byte[10240];     int len = 0;     FileOutputStream fileOutputStream = null;     try {       fileOutputStream = new FileOutputStream(picPath+picName+".jpg");       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();         }       }     }   }    /**    * 图片下载    *    * @param accessToken    * @param mediaId    */   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:/");   } }