code: public void saveToFile(File file)
              throws IOException {
          if (CBStringUtil.isEmptyOrNull(this.url)) {
              return;
          }
          URL url = new URL(this.url);
          URLConnection conn = url.openConnection();
          InputStream is = conn.getInputStream();
          OutputStream os = new FileOutputStream(file);
          byte[] b = new byte[1024];
          int len;
          while ((len = is.read(b)) != -1) {
              os.write(b, 0, len);
          }
          os.close();
          is.close();
      }
docs: 保存指定位置的文件
  
  @param file 保存文件
  @throws IOException IO异常