Examples of time (calculation) total tools: start time and end time of this year, etc

General tools of time operation

package com.aisce.common.utils;

/**
 * @Author pzy
 * @Description: TODO
 * @Version 0.1.0
 */

import java.sql.Timestamp;
import java.util.*;

public class DateUtils {
    //  Get the start time of the day 
    public static Date getDayBegin() {
        Calendar cal = new GregorianCalendar();
        cal.set(Calendar.HOUR_OF_DAY, 0);
        cal.set(Calendar.MINUTE, 0);
        cal.set(Calendar.SECOND, 0);
        cal.set(Calendar.MILLISECOND, 0);
        return cal.getTime();

    }

    //  Get the end time of the day 


    public static Date getDayEnd() {
        Calendar cal = new GregorianCalendar();
        cal.set(Calendar.HOUR_OF_DAY, 23);
        cal.set(Calendar.MINUTE, 59);
        cal.set(Calendar.SECOND, 59);
        return cal.getTime();

    }

    //  Get the start time of yesterday 


    public static Date getBeginDayOfYesterday() {
        Calendar cal = new GregorianCalendar();
        cal.setTime(getDayBegin());
        cal.add(Calendar.DAY_OF_MONTH, -1);
        return cal.getTime();

    }

    //  Get the end time of yesterday 


    public static Date getEndDayOfYesterDay() {
        Calendar cal = new GregorianCalendar();
        cal.setTime(getDayEnd());
        cal.add(Calendar.DAY_OF_MONTH, -1);
        return cal.getTime();

    }

    //  Get the start time of tomorrow 


    public static Date getBeginDayOfTomorrow() {
        Calendar cal = new GregorianCalendar();
        cal.setTime(getDayBegin());
        cal.add(Calendar.DAY_OF_MONTH, 1);

        return cal.getTime();

    }

    //  Get the end time of tomorrow 


    public static Date getEndDayOfTomorrow() {
        Calendar cal = new GregorianCalendar();
        cal.setTime(getDayEnd());
        cal.add(Calendar.DAY_OF_MONTH, 1);
        return cal.getTime();

    }

    //  Get the start time of the week 


    public static Date getBeginDayOfWeek() {
        Date date = new Date();
        if (date == null) {
            return null;

        }
        Calendar cal = Calendar.getInstance();
        cal.setTime(date);
        int dayofweek = cal.get(Calendar.DAY_OF_WEEK);
        if (dayofweek == 1) {
            dayofweek += 7;

        }
        cal.add(Calendar.DATE, 2 - dayofweek);
        return getDayStartTime(cal.getTime());

    }

    //  Get the end time of the week 


    public static Date getEndDayOfWeek() {
        Calendar cal = Calendar.getInstance();
        cal.setTime(getBeginDayOfWeek());
        cal.add(Calendar.DAY_OF_WEEK, 6);
        Date weekEndSta = cal.getTime();
        return getDayEndTime(weekEndSta);

    }

    //  Get the start time of this month 


    public static Date getBeginDayOfMonth() {
        Calendar calendar = Calendar.getInstance();
        calendar.set(getNowYear(), getNowMonth() - 1, 1);
        return getDayStartTime(calendar.getTime());

    }

    //  Get the end time of this month 


    public static Date getEndDayOfMonth() {
        Calendar calendar = Calendar.getInstance();
        calendar.set(getNowYear(), getNowMonth() - 1, 1);
        int day = calendar.getActualMaximum(5);
        calendar.set(getNowYear(), getNowMonth() - 1, day);
        return getDayEndTime(calendar.getTime());
    }

    //  Get the start time of last month 
    public static Date getBeginDayOfLastMonth() {
        Date date = new Date();
        Calendar calendar = Calendar.getInstance();
        calendar.setTime(date);
        calendar.add(calendar.MONTH, -1);
        calendar.set(calendar.DAY_OF_MONTH, 1);
        return getDayStartTime(calendar.getTime());
    }

    //  Get the end time of last month 
    public static Date getEndDayOfLastMonth() {
        Date date = new Date();
        Calendar calendar = Calendar.getInstance();
        calendar.setTime(date);
        calendar.add(calendar.MONTH, -1);
        int day = calendar.getActualMaximum(5);
        calendar.set(calendar.DAY_OF_MONTH, day);
        return getDayEndTime(calendar.getTime());
    }

    //  Get the start time of the year 
    public static Date getBeginDayOfYear() {
        Calendar cal = Calendar.getInstance();
        cal.set(Calendar.YEAR, getNowYear());
// cal.set
        cal.set(Calendar.MONTH, Calendar.JANUARY);
        cal.set(Calendar.DATE, 1);

        return getDayStartTime(cal.getTime());
    }

    //  obtain n The beginning time of years ago 
    public static Date getBeginDayOfLastYear(int n) {
        Calendar cal = Calendar.getInstance();
        cal.set(Calendar.YEAR, getNowYear() - n);
// cal.set
        cal.set(Calendar.MONTH, Calendar.JANUARY);
        cal.set(Calendar.DATE, 1);

        return getDayStartTime(cal.getTime());
    }

    //  obtain n End time years ago 
    public static Date getEndDayOfLastYear(int n) {
        Calendar cal = Calendar.getInstance();
        cal.set(Calendar.YEAR, getNowYear() - n);
        cal.set(Calendar.MONTH, Calendar.DECEMBER);
        cal.set(Calendar.DATE, 31);
        return getDayEndTime(cal.getTime());
    }
    
    //  Get the end time of the year 
    public static Date getEndDayOfYear() {
        Calendar cal = Calendar.getInstance();
        cal.set(Calendar.YEAR, getNowYear());
        cal.set(Calendar.MONTH, Calendar.DECEMBER);
        cal.set(Calendar.DATE, 31);
        return getDayEndTime(cal.getTime());
    }

    //  Get the start time of a date 
    public static Timestamp getDayStartTime(Date d) {
        Calendar calendar = Calendar.getInstance();
        if (null != d)
            calendar.setTime(d);
        calendar.set(calendar.get(Calendar.YEAR), calendar.get(Calendar.MONTH), calendar.get(Calendar.DAY_OF_MONTH), 0,
                0, 0);
        calendar.set(Calendar.MILLISECOND, 0);
        return new Timestamp(calendar.getTimeInMillis());
    }

    //  Get the end time of a date 
    public static Timestamp getDayEndTime(Date d) {
        Calendar calendar = Calendar.getInstance();
        if (null != d)
            calendar.setTime(d);
        calendar.set(calendar.get(Calendar.YEAR), calendar.get(Calendar.MONTH), calendar.get(Calendar.DAY_OF_MONTH), 23,
                59, 59);
        calendar.set(Calendar.MILLISECOND, 999);
        return new Timestamp(calendar.getTimeInMillis());
    }

    //  Get what year this year is 
    public static Integer getNowYear() {
        Date date = new Date();
        GregorianCalendar gc = (GregorianCalendar) Calendar.getInstance();
        gc.setTime(date);
        return Integer.valueOf(gc.get(1));
    }

    //  Get which month this month is 
    public static int getNowMonth() {
        Date date = new Date();
        GregorianCalendar gc = (GregorianCalendar) Calendar.getInstance();
        gc.setTime(date);
        return gc.get(2) + 1;
    }

    //  The number of days obtained by subtracting two dates 
    public static int getDiffDays(Date beginDate, Date endDate) {

        if (beginDate == null || endDate == null) {
            throw new IllegalArgumentException("getDiffDays param is null!");
        }

        long diff = (endDate.getTime() - beginDate.getTime()) / (1000 * 60 * 60 * 24);

        int days = new Long(diff).intValue();

        return days;
    }

    //  The number of milliseconds obtained by subtracting two dates 
    public static long dateDiff(Date beginDate, Date endDate) {
        long date1ms = beginDate.getTime();
        long date2ms = endDate.getTime();
        return date2ms - date1ms;
    }

    //  Get the largest of the two dates 
    public static Date max(Date beginDate, Date endDate) {
        if (beginDate == null) {
            return endDate;
        }
        if (endDate == null) {
            return beginDate;
        }
        if (beginDate.after(endDate)) {
            return beginDate;
        }
        return endDate;
    }

    //  Get the smallest of the two dates 
    public static Date min(Date beginDate, Date endDate) {
        if (beginDate == null) {
            return endDate;
        }
        if (endDate == null) {
            return beginDate;
        }
        if (beginDate.after(endDate)) {
            return endDate;
        }
        return beginDate;
    }

    //  Return to the first month of the quarter of a month 
    public static Date getFirstSeasonDate(Date date) {
        final int[] SEASON = {1, 1, 1, 2, 2, 2, 3, 3, 3, 4, 4, 4};
        Calendar cal = Calendar.getInstance();
        cal.setTime(date);
        int sean = SEASON[cal.get(Calendar.MONTH)];
        cal.set(Calendar.MONTH, sean * 3 - 3);
        return cal.getTime();
    }

    //  Returns the date of the next few days of a date 
    public static Date getNextDay(Date date, int i) {
        Calendar cal = new GregorianCalendar();
        cal.setTime(date);
        cal.set(Calendar.DATE, cal.get(Calendar.DATE) + i);
        return cal.getTime();
    }

    //  Returns the date several days before a date 
    public static Date getFrontDay(Date date, int i) {
        Calendar cal = new GregorianCalendar();
        cal.setTime(date);
        cal.set(Calendar.DATE, cal.get(Calendar.DATE) - i);
        return cal.getTime();
    }

    //  Get the slice date set by day from a certain month of a certain year to a certain month of a certain year （ Date set of interval days ）
    public static List getTimeList(int beginYear, int beginMonth, int endYear, int endMonth, int k) {
        List list = new ArrayList();
        if (beginYear == endYear) {
            for (int j = beginMonth; j <= endMonth; j++) {
                list.add(getTimeList(beginYear, j, k));
            }
        } else {
            {
                for (int j = beginMonth; j < 12; j++) {
                    list.add(getTimeList(beginYear, j, k));
                }

                for (int i = beginYear + 1; i < endYear; i++) {
                    for (int j = 0; j < 12; j++) {
                        list.add(getTimeList(i, j, k));

                    }

                }
                for (int j = 0; j <= endMonth; j++) {
                    list.add(getTimeList(endYear, j, k));

                }

            }
        }
        return list;
    }

    //  Get a collection of sliced dates by day in a certain month of a certain year （ How many days apart is a date set in a month ）
    public static List getTimeList(int beginYear, int beginMonth, int k) {
        List list = new ArrayList();
        Calendar begincal = new GregorianCalendar(beginYear, beginMonth, 1);
        int max = begincal.getActualMaximum(Calendar.DATE);
        for (int i = 1; i < max; i = i + k) {
            list.add(begincal.getTime());
            begincal.add(Calendar.DATE, k);
        }
        begincal = new GregorianCalendar(beginYear, beginMonth, max);
        list.add(begincal.getTime());
        return list;
    }

    //  Get the date of the first day of a month in a year 
    public static Date getStartMonthDate(int year, int month) {
        Calendar calendar = Calendar.getInstance();
        calendar.set(year, month - 1, 1, 0, 0, 0);
        return calendar.getTime();
    }

    //  Get the last day date of a month in a year 
    public static Date getEndMonthDate(int year, int month) {
        Calendar calendar = Calendar.getInstance();
        calendar.set(year, month - 1, 1);
        int day = calendar.getActualMaximum(5);
        calendar.set(year, month - 1, day, 23, 59, 59);
        return calendar.getTime();
    }



}

Test case 1 : 

// test   Case study : 
    public static void main(String[] args) {
        /**
         *  Test one :   Get the start of the year   End time    and   A year ago.   Starting time   And the end time a year ago 
         */
        Date beginDayOfYear = getBeginDayOfYear();
        Date endDayOfYear = getEndDayOfYear();
        
        System.out.println(beginDayOfYear);//2022-01-01 00:00:00.0
        System.out.println(endDayOfYear);//2022-12-31 23:59:59.999

        Date beginDayOfLastYear = getBeginDayOfLastYear(1);// It started a year ago 
        Date endDayOfLastYear = getEndDayOfLastYear(1);// It ended a year ago 

        System.out.println(beginDayOfLastYear);//2021-01-01 00:00:00.0
        System.out.println(endDayOfLastYear);//2021-12-31 23:59:59.999
    }