java格式化文件尺寸大小

	private String formatFileSize(long length) {
		String result = null;
		int sub_string = 0;
		if (length >= 1073741824) {
			sub_string = String.valueOf((float) length / 1073741824).indexOf(
					".");
			result = ((float) length / 1073741824 + "000").substring(0,
					sub_string + 3) + "GB";
		} else if (length >= 1048576) {
			sub_string = String.valueOf((float) length / 1048576).indexOf(".");
			result = ((float) length / 1048576 + "000").substring(0,
					sub_string + 3) + "MB";
		} else if (length >= 1024) {
			sub_string = String.valueOf((float) length / 1024).indexOf(".");
			result = ((float) length / 1024 + "000").substring(0,
					sub_string + 3) + "KB";
		} else if (length < 1024)
			result = Long.toString(length) + "B";
		
		return result;
	}