Java日期处理

日期和时间模式

        // 格式：年－月－日 小时：分钟：秒
	public static final String FORMAT_ONE = "yyyy-MM-dd HH:mm:ss";

	// 格式：年－月－日 小时：分钟
	public static final String FORMAT_TWO = "yyyy-MM-dd HH:mm";

	// 格式：年月日 小时分钟秒
	public static final String FORMAT_THREE = "yyyyMMdd-HHmmss";

	// 格式：年－月－日
	public static final String FORMAT_FOUR = "yyyy-MM-dd";
	
	// 格式：年月日
	public static final String FORMAT_FOUR_NO = "yyyyMMdd";
	
	// 格式：年－月
	public static final String FORMAT_FIVE = "yyyy-MM";

	// 格式：年月
	public static final String FORMAT_SIX = "yyyyMM";

	static final String dayNames[] = { "星期日", "星期一", "星期二", "星期三", "星期四","星期五", "星期六" };

	private static final SimpleDateFormat timeFormat = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");

	public static String stringTostring(String str){
		SimpleDateFormat sf1 = new SimpleDateFormat(FORMAT_FOUR_NO);
		SimpleDateFormat sf2 =new SimpleDateFormat(FORMAT_FOUR);
		String sfstr = "";
		try 
		{
			sfstr = sf2.format(sf1.parse(str));
		} 
		catch (Exception e) {
			e.printStackTrace();
		}
		return sfstr;
	}

	public static java.util.Date stringtoDate(String dateStr, String format)
	{
		Date d = null;
		SimpleDateFormat formater = new SimpleDateFormat(format);
		try
		{
			formater.setLenient(false);//指定日期\时间解析是否不严格
			d = formater.parse(dateStr);
		}
		catch (Exception e)
		{
			e.printStackTrace();
		}
		return d;
	}

	public static String dateToString(java.util.Date date, String format)
	{
		String result = "";
		SimpleDateFormat formater = new SimpleDateFormat(format);
		try
		{
			result = formater.format(date);
		}
		catch (Exception e)
		{
			e.printStackTrace();
		}
		return result;
	}

	/**
	 * @param dateKind 指定处理年、月、日
	 * @param dateStr 指定日期
	 * @param amount 指定长度
	 * @return
	 */
	public static String dateSub(int dateKind, String dateStr, int amount)
	{
		Date date = stringtoDate(dateStr, FORMAT_ONE);
		Calendar calendar = Calendar.getInstance();
		calendar.setTime(date);
		calendar.add(dateKind, amount);
		return dateToString(calendar.getTime(), FORMAT_ONE);
	}

	public static String dateSub(int days)
	{
		Calendar calendar = Calendar.getInstance();
		calendar.add(Calendar.DAY_OF_YEAR, days);
		return dateToString(calendar.getTime(), FORMAT_FOUR);
	}

	public static long timeSub(String firstTime, String secTime)
	{
		long first = stringtoDate(firstTime, FORMAT_ONE).getTime();
		long second = stringtoDate(secTime, FORMAT_ONE).getTime();
		return (second - first) / 1000;
	}

	public static int getDaysOfMonth(String year, String month)
	{
		Date date = stringtoDate(year+"-"+month, FORMAT_FIVE);
		Calendar calendar = Calendar.getInstance();
		calendar.setTime(date);
		return calendar.getActualMaximum(Calendar.DAY_OF_MONTH);
	}

	public static int getDaysOfMonth(int year, int month)
	{
		Calendar calendar = Calendar.getInstance();
		calendar.set(year, month - 1, 1);
		return calendar.getActualMaximum(Calendar.DAY_OF_MONTH);
	}

	public static int getYear(Date date)
	{
		Calendar calendar = Calendar.getInstance();
		calendar.setTime(date);
		return calendar.get(Calendar.YEAR);
	}

	public static int getTodayYear()
	{
		return getYear(new Date());
	}

	public static int getMonth(Date date)
	{
		Calendar calendar = Calendar.getInstance();
		calendar.setTime(date);
		return calendar.get(Calendar.MONTH) + 1;
	}

	public static int getTodayMonth()
	{
		return getMonth(new Date());
	}

	public static long dayDiff(Date date1, Date date2)
	{
		return (date2.getTime() - date1.getTime()) / 86400000;
	}

	public static String getNow()
	{
		Calendar today = Calendar.getInstance();
		return dateToString(today.getTime(), FORMAT_ONE);
	}

	public static String getCurrDate(String format)
	{
		return dateToString(new Date(), format);
	}

	public static boolean isDate(String date)
	{
		StringBuffer reg = new StringBuffer(
				"^((\\d{2}(([02468][048])|([13579][26]))-?((((0?");
		reg.append("[13578])|(1[02]))-?((0?[1-9])|([1-2][0-9])|(3[01])))");
		reg.append("|(((0?[469])|(11))-?((0?[1-9])|([1-2][0-9])|(30)))|");
		reg.append("(0?2-?((0?[1-9])|([1-2][0-9])))))|(\\d{2}(([02468][12");
		reg.append("35679])|([13579][01345789]))-?((((0?[13578])|(1[02]))");
		reg.append("-?((0?[1-9])|([1-2][0-9])|(3[01])))|(((0?[469])|(11))");
		reg.append("-?((0?[1-9])|([1-2][0-9])|(30)))|(0?2-?((0?[");
		reg.append("1-9])|(1[0-9])|(2[0-8]))))))");
		Pattern p = Pattern.compile(reg.toString());
		return p.matcher(date).matches();
	}

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