设置日期

public static Date getTime(Integer day, Integer hour, Integer minute, Integer second) {
		Calendar c = Calendar.getInstance();
		if (day != null)
			c.add(Calendar.DAY_OF_MONTH, day);
		if (hour != null)
			c.set(Calendar.HOUR_OF_DAY, hour);
		if (minute != null)
			c.set(Calendar.MINUTE, minute);
		if (second != null)
			c.set(Calendar.SECOND, second);
		return c.getTime();
	}

//随手记录