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:/"); 
  } 
}