@Override
	public RepeatStatus execute(StepContribution contribution, ChunkContext chunkContext) throws IOException {
		ensureDirectory();

		String name = directory + FILE_SEPARATOR + fileName + '.' + fileExtension;
		DateFormat dateFormat = new SimpleDateFormat(format);
		PrintWriter writer = null;

		try {
			writer = new PrintWriter(new BufferedWriter(new FileWriter(name)));
			writer.println(dateFormat.format(new Date()));
		}
		finally {
			if (writer != null) {
				writer.close();
			}
		}

		return RepeatStatus.FINISHED;
	}
Time stamp date format.

@see java.text.SimpleDateFormat
extensions/spring-xd-extension-batch/src/main/java/org/springframework/batch/integration/x/TimestampFileTasklet.java