Java对日期Date类进行日期加减运算，年份加减，月份加减

package com.cy;

import java.security.InvalidParameterException;
import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.ArrayList;
import java.util.Calendar;
import java.util.Date;
import java.util.HashMap;
import java.util.Map;

public class DateUtils {
    private static final long MILLIS_IN_A_SECOND = 1000;

    private static final long SECONDS_IN_A_MINUTE = 60;

    private static final int MONTHS_IN_A_YEAR = 12;

    /**
     * 获得指定日期之后一段时期的日期。例如某日期之后3天的日期等 时间为23:59:59。
     * 
     * @param origDate
     *            基准日期
     * @param amount
     *            时间数量
     * @param timeUnit
     *            时间单位，如年、月、日等。用Calendar中的常量代表
     * @return {@link Date}
     */
    public static final Date dateAfter(Date origDate, int amount, int timeUnit) {
        Calendar calendar = Calendar.getInstance();
        calendar.setTime(origDate);
        // 将小时至0
        // calendar.set(Calendar.HOUR_OF_DAY, 23);
        // 将分钟至0
        // calendar.set(Calendar.MINUTE, 59);
        // 将秒至0
        // calendar.set(Calendar.SECOND, 59);
        // 将毫秒至0
        // calendar.set(Calendar.MILLISECOND, 0);
        calendar.add(timeUnit, amount);
        return calendar.getTime();
    }

    /**
     * 获得指定日期之后一段时期的日期。例如某日期之后3天的日期等。
     * 
     * @param origDate
     *            基准日期
     * @param amount
     *            时间数量
     * @param timeUnit
     *            时间单位，如年、月、日等。用Calendar中的常量代表
     * @return {@link Date}
     */
    public static final Date timeAfter(Date origDate, int amount, int timeUnit) {
        Calendar calendar = Calendar.getInstance();
        calendar.setTime(origDate);
        calendar.add(timeUnit, amount);
        return calendar.getTime();
    }

    /**
     * 获得指定日期之前一段时期的日期。例如某日期之前3天的日期等。
     * 
     * @param origDate
     *            基准日期
     * @param amount
     *            时间数量
     * @param timeUnit
     *            时间单位，如年、月、日等。用Calendar中的常量代表
     * @return {@link Date}
     */
    public static final Date dateBefore(Date origDate, int amount, int timeUnit) {
        Calendar calendar = Calendar.getInstance();
        calendar.add(timeUnit, -amount);
        return calendar.getTime();
    }

    /**
     * 根据年月日构建日期对象。注意月份是从1开始计数的，即month为1代表1月份。
     * 
     * @param year
     *            年
     * @param month
     *            月。注意1代表1月份，依此类推。
     * @param day
     *            日
     * @return {@link Date}
     */
    public static Date date(int year, int month, int date) {
        Calendar calendar = Calendar.getInstance();
        calendar.set(year, month - 1, date, 0, 0, 0);
        calendar.set(Calendar.MILLISECOND, 0);
        return calendar.getTime();
    }

    /**
     * 计算两个日期（不包括时间）之间相差的周年数
     * 
     * @param date1
     *            开始时间
     * @param date2
     *            结束时间
     * @return {@link Integer}
     */
    public static int getYearDiff(Date date1, Date date2) {
        if (date1 == null || date2 == null) {
            throw new InvalidParameterException("date1 and date2 cannot be null!");
        }
        if (date1.after(date2)) {
            throw new InvalidParameterException("date1 cannot be after date2!");
        }

        Calendar calendar = Calendar.getInstance();
        calendar.setTime(date1);
        int year1 = calendar.get(Calendar.YEAR);
        int month1 = calendar.get(Calendar.MONTH);
        int day1 = calendar.get(Calendar.DATE);

        calendar.setTime(date2);
        int year2 = calendar.get(Calendar.YEAR);
        int month2 = calendar.get(Calendar.MONTH);
        int day2 = calendar.get(Calendar.DATE);

        int result = year2 - year1;
        if (month2 < month1) {
            result--;
        } else if (month2 == month1 && day2 < day1) {
            result--;
        }
        return result;
    }

    /**
     * 计算两个日期（不包括时间）之间相差的整月数
     * 
     * @param date1
     *            开始时间
     * @param date2
     *            结束时间
     * @return {@link Integer}
     */
    public static int getMonthDiff(Date date1, Date date2) {
        if (date1 == null || date2 == null) {
            throw new InvalidParameterException("date1 and date2 cannot be null!");
        }
        if (date1.after(date2)) {
            throw new InvalidParameterException("date1 cannot be after date2!");
        }

        Calendar calendar = Calendar.getInstance();
        calendar.setTime(date1);
        int year1 = calendar.get(Calendar.YEAR);
        int month1 = calendar.get(Calendar.MONTH);
        int day1 = calendar.get(Calendar.DATE);

        calendar.setTime(date2);
        int year2 = calendar.get(Calendar.YEAR);
        int month2 = calendar.get(Calendar.MONTH);
        int day2 = calendar.get(Calendar.DATE);

        int months = 0;
        if (day2 >= day1) {
            months = month2 - month1;
        } else {
            months = month2 - month1 - 1;
        }
        return (year2 - year1) * MONTHS_IN_A_YEAR + months;
    }

    /**
     * 统计两个日期之间包含的天数。包含date1，但不包含date2
     * 
     * @param date1
     *            开始时间
     * @param date2
     *            结束时间
     * @return {@link Integer}
     * @throws ParseException
     */
    public static int getDayDiff(Date date1, Date date2) {
        if (date1 == null || date2 == null) {
            throw new InvalidParameterException("date1 and date2 cannot be null!");
        }
        SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd");
        Date smdate;
        try {
            smdate = sdf.parse(sdf.format(date1));
            Date bdate = sdf.parse(sdf.format(date2));
            Calendar cal = Calendar.getInstance();
            cal.setTime(smdate);
            long time1 = cal.getTimeInMillis();
            cal.setTime(bdate);
            long time2 = cal.getTimeInMillis();
            long between_days = (time2 - time1) / (1000 * 3600 * 24);
            return Integer.parseInt(String.valueOf(between_days));
        } catch (ParseException e) {
            e.printStackTrace();
        }
        return 0;
    }

    /**
     * 计算time2比time1晚多少分钟，忽略日期部分
     * 
     * @param time1
     * @param time2
     * @return
     */
    public static int getMinuteDiffByTime(Date time1, Date time2) {
        long startMil = 0;
        long endMil = 0;
        Calendar calendar = Calendar.getInstance();
        calendar.setTime(time1);
        calendar.set(1900, 1, 1);
        startMil = calendar.getTimeInMillis();
        calendar.setTime(time2);
        calendar.set(1900, 1, 1);
        endMil = calendar.getTimeInMillis();
        return (int) ((endMil - startMil) / MILLIS_IN_A_SECOND / SECONDS_IN_A_MINUTE);
    }

    /**
     * 计算时间是否是同一天
     * 
     * @param dateA
     * @param dateB
     * @return
     */
    public static boolean areSameDay(Date dateA, Date dateB) {
        Calendar calDateA = Calendar.getInstance();
        calDateA.setTime(dateA);

        Calendar calDateB = Calendar.getInstance();
        calDateB.setTime(dateB);

        return calDateA.get(Calendar.YEAR) == calDateB.get(Calendar.YEAR)
                && calDateA.get(Calendar.MONTH) == calDateB.get(Calendar.MONTH)
                && calDateA.get(Calendar.DAY_OF_MONTH) == calDateB.get(Calendar.DAY_OF_MONTH);
    }

    /**
     * @Title: getCurrYearLast
     * @Description: 获取某年最后一天
     * @param date
     * @return Date
     */
    public static Date getCurrYearLast(Date date) {
        Calendar currCal = Calendar.getInstance();
        currCal.setTime(date);
        int currentYear = currCal.get(Calendar.YEAR);
        return getYearLast(currentYear);
    }

    private static Date getYearLast(int year) {
        Calendar calendar = Calendar.getInstance();
        calendar.clear();
        calendar.set(Calendar.YEAR, year);

        calendar.roll(Calendar.DAY_OF_YEAR, -1);
        // 将小时至0
        calendar.set(Calendar.HOUR_OF_DAY, 23);
        // 将分钟至0
        calendar.set(Calendar.MINUTE, 59);
        // 将秒至0
        calendar.set(Calendar.SECOND, 59);
        // 将毫秒至0
        calendar.set(Calendar.MILLISECOND, 0);

        Date currYearLast = calendar.getTime();
        return currYearLast;
    }
    /*
     * private static Date getYearLast(int year) { Calendar calendar =
     * Calendar.getInstance(); calendar.clear(); calendar.set(Calendar.YEAR,
     * year); calendar.roll(Calendar.DAY_OF_YEAR, -1); Date currYearLast =
     * calendar.getTime(); return currYearLast; }
     */
    /**
     * 
     * @param args
     * @throws ParseException
     * 
     * 根据结算周期数  对开始时间与结束时间进行分段
     */
    public static void main(String[] args) throws ParseException {
        /*开始时间*/
        Date startDate = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss").parse("2017-1-20 10:31:36");
        /*结束时间*/
        Date endDate = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss").parse("2017-5-12 10:31:36");
        /*周期数*/
        int solt = 2;
        ArrayList<Map<String, Object>> list = new ArrayList<>();
        
        while (startDate.getTime()<endDate.getTime()) {
            Map<String, Object> map = new HashMap<>();
            map.put("开始时间",new SimpleDateFormat("yyyy-MM-dd HH:mm:ss").format(startDate));
            startDate=dateAfter(startDate, solt, Calendar.MONTH);
            if (startDate.getTime()>endDate.getTime()) {
                map.put("结束时间",new SimpleDateFormat("yyyy-MM-dd HH:mm:ss").format(endDate));
                
            } else {
                map.put("结束时间",new SimpleDateFormat("yyyy-MM-dd HH:mm:ss").format(startDate));
            }
            list.add(map);
        }
        System.out.println(list);
    }
}