JAVA简单时间工具类

通过以下代码可以获取当前月的第一天和最后一天

public Map<String, Date> getCurrentMonthDays(Date date) {
        Map<String, Date> map = new HashMap<>();
        // 获取前月的第一天
        Calendar calendar = Calendar.getInstance();
        calendar.setTime(date);

        calendar.add(Calendar.MONTH, 0);
        calendar.set(Calendar.DAY_OF_MONTH, 1);
        map.put("beginDay", calendar.getTime());
        // 获取前月的最后一天
        //calendar = Calendar.getInstance();
        calendar.add(Calendar.MONTH, 1);
        calendar.set(Calendar.DAY_OF_MONTH, 0);
        map.put("endDay", calendar.getTime());
        return map;
}

获取当前季度的第一天和最后一天

public static String[] getSeasonDay (Date date){
            SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd");

            Calendar c = Calendar.getInstance();
            c.setTime(date);
            int month = c.get(Calendar.MONTH);
            //数学原理：
            // moth属性=月份-1，3个月=1季度，
            // 那么季度的最大月份÷3 =季度，(月份-1(即month属性))÷3向下取整 = 上一个季度；
            // 上个季度*3=上个季度最大月份=当前季度最小月份-1=当前季度最小月份month属性
            Calendar startC = Calendar.getInstance();
            startC.setTime(date);
            int seasonStartMonthNum = (int) (Math.floor(month / 3.0) * 3);
            startC.set(Calendar.MONTH, seasonStartMonthNum);
            startC.set(Calendar.DAY_OF_MONTH, 1);
            String seasonStartDateStr = sdf.format(startC.getTime());
            Calendar endC = Calendar.getInstance();
            endC.setTime(date);
            //当前季度最大月=当前最小月+2；
            int seasonEndMonthNum;
            seasonEndMonthNum = seasonStartMonthNum + 2;
            endC.set(Calendar.MONTH, seasonEndMonthNum);
            endC.set(Calendar.DAY_OF_MONTH, endC.getActualMaximum(Calendar.DAY_OF_MONTH));
            String seasonEndDateStr = sdf.format(endC.getTime());
            return new String[]{seasonStartDateStr, seasonEndDateStr};
}

获取当前半年的第一天和最后一天

public static String[] getHalfYearDay (Date date){

	      SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd");
	
	      Calendar c = Calendar.getInstance();
	      c.setTime(date);
	      int month = c.get(Calendar.MONTH);
	      //数学原理：
	      // moth属性=月份-1，6个月=半年，
	      // 那么半年的最大月份÷6 =半年，(月份-1(即month属性))÷6向下取整 = 上半年；
	      // 上一半年*6=上一半年最大月份=当前半年最小月份-1=当前半年最小月份month属性
	      Calendar startC = Calendar.getInstance();
	      startC.setTime(date);
	      int halfStartMonthNum = (int) (Math.floor(month / 6.0) * 6);
	      startC.set(Calendar.MONTH, halfStartMonthNum);
	      startC.set(Calendar.DAY_OF_MONTH, 1);
	      String halfStartDateStr = sdf.format(startC.getTime());
	      Calendar endC = Calendar.getInstance();
	      endC.setTime(date);
	      //当前半年最大月=当前最小月+5；
	      int halfEndMonthNum;
	      halfEndMonthNum = halfStartMonthNum + 5;
	      endC.set(Calendar.MONTH, halfEndMonthNum);
	      endC.set(Calendar.DAY_OF_MONTH, endC.getActualMaximum(Calendar.DAY_OF_MONTH));
	      String halfEndDateStr = sdf.format(endC.getTime());
	      return new String[]{halfStartDateStr, halfEndDateStr};
}

获取当前年的第一天和最后一天

public static String[] getYearDay (Date date){

            SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd");

            Calendar c = Calendar.getInstance();
            c.setTime(date);

            Calendar startC = Calendar.getInstance();
            startC.setTime(date);
            startC.set(Calendar.MONTH, 0);
            startC.set(Calendar.DAY_OF_MONTH, 1);
            String halfStartDateStr = sdf.format(startC.getTime());
            Calendar endC = Calendar.getInstance();
            endC.setTime(date);

            endC.set(Calendar.MONTH, 11);
            endC.set(Calendar.DAY_OF_MONTH, endC.getActualMaximum(Calendar.DAY_OF_MONTH));
            String halfEndDateStr = sdf.format(endC.getTime());
            return new String[]{halfStartDateStr, halfEndDateStr};
}

获取当前周的第一天和最后一天

public static String[] getCurrentWeekTimeFrame (Date date){
            SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd");
            Calendar calendar = Calendar.getInstance();
            calendar.setTime(date);
            calendar.setTimeZone(TimeZone.getTimeZone("GMT+8"));
            //start of the week
            if (calendar.get(Calendar.DAY_OF_WEEK) == Calendar.SUNDAY) {
                calendar.add(Calendar.DAY_OF_YEAR, -1);
            }
            calendar.add(Calendar.DAY_OF_WEEK, -(calendar.get(Calendar.DAY_OF_WEEK) - 2));
            calendar.set(Calendar.HOUR_OF_DAY, 0);
            calendar.set(Calendar.MINUTE, 0);
            calendar.set(Calendar.SECOND, 0);
            calendar.set(Calendar.MILLISECOND, 0);

            Date startTime = calendar.getTime();
            //end of the week
            calendar.add(Calendar.DAY_OF_WEEK, 6);
            calendar.set(Calendar.HOUR_OF_DAY, 23);
            calendar.set(Calendar.MINUTE, 59);
            calendar.set(Calendar.SECOND, 59);
            calendar.set(Calendar.MILLISECOND, 999);
            Date endTime = calendar.getTime();
            return new String[]{sdf.format(startTime), sdf.format(endTime)};
}