JAVA TOOL(DATE)

1.获得当前日期

public static String getTodayDate() {
		Calendar today = Calendar.getInstance();
		String format= "yyyy-MM-dd";
		SimpleDateFormat sdf= new SimpleDateFormat(format);
		return sdf.format(today.getTime());
	}

2.获得当前时间

public static String getTodayTime() {
		Calendar today = Calendar.getInstance();
		String format= "yyyy-MM-dd HH:mm:ss";
		SimpleDateFormat sdf= new SimpleDateFormat(format);
		return sdf.format(today.getTime());
	}

3.获得上周是*年的第？周

public static int getPreWeek() {
		Calendar thisWeek = Calendar.getInstance();
		thisWeek.add(Calendar.WEEK_OF_YEAR, -1);
		int lastWeek = thisWeek.get(Calendar.WEEK_OF_YEAR);
		return lastWeek;
	}

4.给时间增加秒数

public static Date addSecond(Date date, int second) {

		if (date != null) {

			Calendar cal = Calendar.getInstance();
			cal.setTime(date);
			cal.setTimeZone(TimeZone.getDefault());
			long Time = (cal.getTimeInMillis() / 1000) + second;
			cal.setTimeInMillis(Time * 1000);
			return cal.getTime();
		} else {
			return null;
		}
	}

5.给时间减去秒数

public static Date subtractSecond(Date date, int second) {

		if (date != null) {
			Calendar cal = Calendar.getInstance();
			cal.setTime(date);
			cal.setTimeZone(TimeZone.getDefault());
			long Time = (cal.getTimeInMillis() / 1000) - second;
			cal.setTimeInMillis(Time * 1000);
			return cal.getTime();
		} else {
			return null;
		}
	}

6. 根据时间获取(utcMs)时间毫秒##

public static Long getUtcMsTime(Date date) {
		if (date != null) {
			Calendar cal = Calendar.getInstance();
			cal.setTime(date);
			cal.setTimeZone(TimeZone.getDefault());
			return cal.getTimeInMillis();
		} else {
			return null;
		}
	}

7.获得上周开始时间(周一)

	public static String getPreWeekStartDay() {
		Calendar cal = Calendar.getInstance();
		String format = "yyyy-MM-dd";
		SimpleDateFormat sdf = new SimpleDateFormat(format);
		cal.set(Calendar.DAY_OF_WEEK, Calendar.MONDAY);
		cal.add(Calendar.WEEK_OF_MONTH, -1);
		return sdf.format(cal.getTime());
	}

8.获得上周结束时间(周日)

	public static String getPreWeekEndDay() {
		Calendar cal = Calendar.getInstance();
		String format = "yyyy-MM-dd";
		SimpleDateFormat sdf = new SimpleDateFormat(format);
		cal.set(Calendar.DAY_OF_WEEK, Calendar.SUNDAY);
		cal.add(Calendar.WEEK_OF_MONTH, 0);
		return sdf.format(cal.getTime());
	}

9.获得上月开始时间

public static String getPreMonthStartDay() {
		GregorianCalendar gcLast = (GregorianCalendar) Calendar.getInstance();
		String format = "yyyy-MM-dd";
		SimpleDateFormat sdf = new SimpleDateFormat(format);
		Calendar calendar = Calendar.getInstance();
		calendar.setTime(new Date());
		calendar.add(Calendar.MONTH, -1);
		Date theDate = calendar.getTime();
		gcLast.setTime(theDate);
		gcLast.set(Calendar.DAY_OF_MONTH, 1);
		return sdf.format(gcLast.getTime());
	}

10. 获得上月结束时间##

public static String getPreMonthEndDay() {
		GregorianCalendar gcLast = (GregorianCalendar) Calendar.getInstance();
		String format = "yyyy-MM-dd";
		SimpleDateFormat sdf = new SimpleDateFormat(format);
		Calendar calendar = Calendar.getInstance();
		calendar.setTime(new Date());
		Date theDate = calendar.getTime();
		gcLast.setTime(theDate);
		gcLast.set(Calendar.DAY_OF_MONTH, 0);
		return sdf.format(gcLast.getTime());
	}
	```
	

11.获取某年某月第一日
------------

public static String getFirstDayOfMonth(int year, int month) {
	Calendar cal = Calendar.getInstance();
	cal.set(Calendar.YEAR, year);
	cal.set(Calendar.MONTH, month);
	cal.set(Calendar.DAY_OF_MONTH, cal.getMinimum(Calendar.DATE));
	return new SimpleDateFormat("yyyy-MM-dd ").format(cal.getTime());
}

12.获取某年某月最后一日
-------------

public static String getLastDayOfMonth(int year, int month) {
	Calendar cal = Calendar.getInstance();
	cal.set(Calendar.YEAR, year);
	cal.set(Calendar.MONTH, month);
	cal.set(Calendar.DAY_OF_MONTH, cal.getActualMaximum(Calendar.DATE));
	return new SimpleDateFormat("yyyy-MM-dd ").format(cal.getTime());
}