关于时间戳和日期，时间的互换

/**
	 * 日期转时间戳
	 */
	public static long dateToTimestamp(String datetime) {
		SimpleDateFormat sdr = new SimpleDateFormat("yyyy-MM-dd", Locale.CHINA);
		long timestamp = 0;
		try {
			Date date = sdr.parse(datetime);
			timestamp = date.getTime();
		} catch (ParseException e) {
			e.printStackTrace();
		}
		return timestamp;
	}

	/**
	 * 时间戳转日期
	 */
	public static String timestampToDate(String datetime) {
		SimpleDateFormat sdr = new SimpleDateFormat("yyyy-MM-dd",
				Locale.getDefault());
		long timestamp = Long.valueOf(datetime);
		Date date = new Date(timestamp);
		return sdr.format(date);
	}

        public static String formateMils(Long millSec) {
		Date date = new Date(millSec);
		SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
		return sdf.format(date);
	}

/**
	 * @param time
	 *            时间戳转换成时分秒
	 * @return 时：分：秒
	 */
	public static String getFormatFilterTime(long time) {
		time = time / 1000;
		long second = time % 60;
		long minute = (time % 3600) / 60;
		long hour = time / 3600;

		// 秒显示两位
		String strSecond = ("00" + second)
				.substring(("00" + second).length() - 2);
		// 分显示两位
		String strMinute = ("00" + minute)
				.substring(("00" + minute).length() - 2);
		// 时显示两位
		String strHour = ("00" + hour).substring(("00" + hour).length() - 2);

		return strHour.equals("00") ? strMinute + ":" + strSecond : strHour
				+ ":" + strMinute + ":" + strSecond;
	}

/**
 *用日历获取日期时间
 */

// 获取某天0点的时间
	public static Long getDayStartTime(Calendar calendar) {
		calendar.set(Calendar.HOUR_OF_DAY, 0);
		calendar.set(Calendar.MINUTE, 0);
		calendar.set(Calendar.SECOND, 0);
		calendar.set(Calendar.MILLISECOND, 0);
		return calendar.getTime().getTime();
	}

	// 获取某天23点59分59秒的时间，也就是一天最后的时间
	public static Long getDayEndTime(Calendar calendar) {
		calendar.set(Calendar.HOUR_OF_DAY, 23);
		calendar.set(Calendar.MINUTE, 59);
		calendar.set(Calendar.SECOND, 59);
		calendar.set(Calendar.MILLISECOND, 59);
		return calendar.getTime().getTime();
	}