Javaは、現在の時刻の前の期間と特定の期間の時間収集をどのように取得しますか

1.関連する日付処理

public class DateUtil {
    
    
	public static SimpleDateFormat sdf=new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
	private static SimpleDateFormat sdf2=new SimpleDateFormat("yyyy-MM-dd-HH-mm-ss");
	public static SimpleDateFormat sdf3=new SimpleDateFormat("yyyy-MM-dd HH:mm");
	private static DecimalFormat decimalFormat=new DecimalFormat("#####0.## S");

	/**
	 * 获取当前时间的晚上23点59分59秒
	 *
	 * @param current
	 * @return
	 */
	public static Date getEndDate(Date current) {
    
    
		Calendar c = Calendar.getInstance();
		c.setTime(current);
		c.set(Calendar.HOUR_OF_DAY, 23);
		c.set(Calendar.MINUTE, 59);
		c.set(Calendar.SECOND, 59);
		return c.getTime();
	}

	/**
	 * 获取当前时间的0时0分0秒
	 * @param current
	 * @return
	 */
	public static Date getStartDate(Date current){
    
    
         Calendar calendarStart = Calendar.getInstance();
         calendarStart.setTime(current);
         calendarStart.set(calendarStart.get(Calendar.YEAR),
                         calendarStart.get(Calendar.MONTH),
                         calendarStart.get(Calendar.DATE),
                         0, 0, 0);
         current = calendarStart.getTime();
         return current;
	 }


	/**
	 * 获取当前月第一天
	 *
	 * @return
	 */
	public static Date getFirstDay() {
    
    
		Calendar c = Calendar.getInstance();
		c.add(Calendar.MONTH, 0);
		c.set(Calendar.DAY_OF_MONTH, 1);// 设置为1号,当前日期既为本月第一天
		return c.getTime();
	}

	/**
	 * 获取当前月最后一天
	 *
	 * @return
	 */
	public static Date getEndDay() {
    
    
		Calendar ca = Calendar.getInstance();
		ca.set(Calendar.DAY_OF_MONTH, ca.getActualMaximum(Calendar.DAY_OF_MONTH));
		return ca.getTime();
	}

	/**
	 * 获取当月天数
	 *
	 * @return
	 */
	public static int getCurrentMonthDay() {
    
    
		Calendar a = Calendar.getInstance();
		a.set(Calendar.DATE, 1);
		a.roll(Calendar.DATE, -1);
		int maxDate = a.get(Calendar.DATE);
		return maxDate;
	}


	/**
	 * 获取一段时间内所有的天数
	 *
	 * @param dBegin
	 * @param dEnd
	 * @return
	 */
	public static List<String> findDates(Date dBegin, Date dEnd) {
    
    
		SimpleDateFormat formart = new SimpleDateFormat("yyyy-MM-dd");
		List<String> lDate = new ArrayList<>();
		lDate.add(formart.format(dBegin));
		Calendar calBegin = Calendar.getInstance();
		calBegin.setTime(dBegin);
		Calendar calEnd = Calendar.getInstance();
		// 使用给定的 Date 设置此 Calendar 的时间
		calEnd.setTime(dEnd);
		// 测试此日期是否在指定日期之后
		while (dEnd.after(calBegin.getTime())) {
    
    
			// 根据日历的规则，为给定的日历字段添加或减去指定的时间量
			calBegin.add(Calendar.DAY_OF_MONTH, 1);
			lDate.add(formart.format(calBegin.getTime()));
		}
		return lDate;
	}

	public static String getNow() {
    
    
		return sdf.format(Calendar.getInstance().getTime());
	}

	public static String getNowId() {
    
    
		return sdf2.format(Calendar.getInstance().getTime());
	}

	/**
	 * 将 yyyy-MM-dd HH:mm 格式的字符串转化为Date
	 * @param dateString
	 * @return
	 */
	public static Date getDateByFormat3(String dateString){
    
    
		Date date=null;
		if(dateString==null) return null;
		try {
    
    
			date=sdf3.parse(dateString);
		} catch (ParseException e) {
    
    
			e.printStackTrace();
		}
		return date;
	}



	public static String getCronByDate(Date time){
    
    
		Calendar calendar=Calendar.getInstance();
		calendar.setTime(time);
		//0 15 10 * * ? 2005
		StringBuffer sb=new StringBuffer();
		sb.append(calendar.get(Calendar.SECOND)).append(" ");//秒
		sb.append(calendar.get(Calendar.MINUTE)).append(" ");//分
		sb.append(calendar.get(Calendar.HOUR_OF_DAY)).append(" ");//时
		sb.append(calendar.get(Calendar.DAY_OF_MONTH)).append(" ");//日期
		sb.append(calendar.get(Calendar.MONTH)+1).append(" ");//月份
		sb.append("?").append(" ");//星期
		sb.append(calendar.get(Calendar.YEAR));//年

		return sb.toString();
	}

    public static String secToTime(int time) {
    
    
        String timeStr = null;
        int hour = 0;
        int minute = 0;
        int second = 0;
        if (time <= 0)
            return "00:00:00";
        else {
    
    
            minute = time / 60;
            if (minute < 60) {
    
    
                second = time % 60;
                timeStr = "00:"+unitFormat(minute) + ":" + unitFormat(second);
            } else {
    
    
                hour = minute / 60;
                if (hour > 99)
                    return "99:59:59";
                minute = minute % 60;
                second = time - hour * 3600 - minute * 60;
                timeStr = unitFormat(hour) + ":" + unitFormat(minute) + ":" + unitFormat(second);
            }
        }
        return timeStr;
    }

    public static String msToSec(long time) {
    
    
    	return decimalFormat.format(time/1000f);
    }


    public static String unitFormat(int i) {
    
    
        String retStr = null;
        if (i >= 0 && i < 10)
            retStr = "0" + Integer.toString(i);
        else
            retStr = "" + i;
        return retStr;
    }


    public static void main(String[] args) {
    
    

   	}

    /**
     * 获取当前时间，指定前面多少小时的时间
     * @param ihour 前几个小时
     * @return
     */
    public static String getBeforeHourTime(int ihour){
    
    
        String returnstr = "";
        Calendar calendar = Calendar.getInstance();
        calendar.set(Calendar.HOUR_OF_DAY, calendar.get(Calendar.HOUR_OF_DAY) - ihour);
        SimpleDateFormat df = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
        returnstr = df.format(calendar.getTime());
        return returnstr;
    }

    /**
     * 获取当前时间的前一天
     * @param date
     * @return
     */
    public static Date getPerDay(Date date) {
    
    
        Calendar calendar = Calendar.getInstance();
        calendar.setTime(date);
        calendar.add(Calendar.DAY_OF_MONTH, -1);
        date = calendar.getTime();
        return date;
    }

	/**
	 * 获取当前时间的前三十天
	 * @param date
	 * @return
	 */
	public static Date getPer30Day(Date date) {
    
    
		Calendar calendar = Calendar.getInstance();
		calendar.setTime(date);
		calendar.add(Calendar.DAY_OF_MONTH, -30);
		date = calendar.getTime();
		return date;
	}

	/**
     * 获取当前时间的后一天
     * @param date
     * @return
     */
    public static Date getNextDay(Date date) {
    
    
        Calendar calendar = Calendar.getInstance();
        calendar.setTime(date);
        calendar.add(Calendar.DAY_OF_MONTH, 1);
        date = calendar.getTime();
        return date;
    }

}