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);
}
}