code: public static byte[] zlib(File file, int level) {
  		BufferedInputStream in = null;
  		try {
  			in = FileUtil.getInputStream(file);
  			return zlib(in, level, (int)file.length());
  		} finally {
  			IoUtil.close(in);
  		}
  	}
docs: Zlib压缩文件
  
  @param file 被压缩的文件
  @param level 压缩级别
  @return 压缩后的字节流
  @since 4.1.4