private static void listObject(BaiduBCS baiduBCS) {
		ListObjectRequest listObjectRequest = new ListObjectRequest(bucket);
		listObjectRequest.setStart(0);
		listObjectRequest.setLimit(20);
		// ------------------by dir
		{
			// prefix must start with '/' and end with '/'
			listObjectRequest.setPrefix("/log/");
			listObjectRequest.setListModel(2);
		}
		// ------------------only object
		{
			// prefix must start with '/'
			// listObjectRequest.setPrefix("/1/");
		}
		BaiduBCSResponse<ObjectListing> response = baiduBCS
				.listObject(listObjectRequest);
		log.info("we get [" + response.getResult().getObjectSummaries().size()
				+ "] object record.");
		for (ObjectSummary os : response.getResult().getObjectSummaries()) {
			log.info(os.toString());
		}
	}