1.时间格式转换DateUtil

一、介绍

主要针对于时间date进行转换等一系列操作的工具类,包括时间转字符串,字符串转时间等。

/**
 * @author sunxw
 * @create_time 2021/7/9 15:21
 * @since 1.0-Snapshoot
 */
import java.sql.Timestamp;
import java.text.DateFormat;
import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.ArrayList;
import java.util.Calendar;
import java.util.Date;
import java.util.GregorianCalendar;
import java.util.HashMap;
import java.util.Iterator;
import java.util.LinkedHashMap;
import java.util.List;

public class DateUtil{

    // ==格式到年==
    /**
     * 日期格式,年份,例如:2004,2008
     */
    public static final String DATE_FORMAT_YYYY = "yyyy";

    /**
     * 日期格式,年份和月份,例如:200707,200808
     */
    public static final String DATE_FORMAT_YYYYMM = "yyyyMM";

    /**
     * 日期格式,年份和月份,例如:200707,2008-08
     */
    public static final String DATE_FORMAT_YYYY_MM = "yyyy-MM";

    /**
     * 日期格式,年月日,例如:050630,080808
     */
    public static final String DATE_FORMAT_YYMMDD = "yyMMdd";

    /**
     * 日期格式,年月日,用横杠分开,例如:06-12-25,08-08-08
     */
    public static final String DATE_FORMAT_YY_MM_DD = "yy-MM-dd";

    /**
     * 日期格式,年月日,例如:20050630,20080808
     */
    public static final String DATE_FORMAT_YYYYMMDD = "yyyyMMdd";

    /**
     * 日期格式,年月日时,例如:2021072815
     */
    public static final String DATE_FORMAT_YYYYMMDDHH = "yyyyMMddHH";

    /**
     * 日期格式,年月日,用横杠分开,例如:2006-12-25,2008-08-08
     */
    public static final String DATE_FORMAT_YYYY_MM_DD = "yyyy-MM-dd";

    /**
     * 日期格式,年月日,例如:2016.10.05
     */
    public static final String DATE_FORMAT_POINTYYYYMMDD = "yyyy.MM.dd";

    /**
     * 日期格式,年月日,例如:2016年10月05日
     */
    public static final String DATE_TIME_FORMAT_YYYY年MM月DD日 = "yyyy年MM月dd日";


    // ==格式到年月日 时分 ==

    /**
     * 日期格式,年月日时分,例如:200506301210,200808081210
     */
    public static final String DATE_FORMAT_YYYYMMDDHHmm = "yyyyMMddHHmm";

    /**
     * 日期格式,年月日时分,例如:20001230 12:00,20080808 20:08
     */
    public static final String DATE_TIME_FORMAT_YYYYMMDD_HH_MI = "yyyyMMdd HH:mm";

    /**
     * 日期格式,年月日时分,例如:2000-12-30 12:00,2008-08-08 20:08
     */
    public static final String DATE_TIME_FORMAT_YYYY_MM_DD_HH_MI = "yyyy-MM-dd HH:mm";

    /**
     * 日期格式,年月日时分秒,例如:20001230120000,20080808200808
     */
    public static final String DATE_TIME_FORMAT_YYYYMMDDHHMISS = "yyyyMMddHHmmss";

    /**
     * 日期格式,年月日时分秒,年月日用横杠分开,时分秒用冒号分开
     * 例如:2005-05-10 23:20:00,2008-08-08 20:08:08
     */
    public static final String DATE_TIME_FORMAT_YYYY_MM_DD_HH_MI_SS = "yyyy-MM-dd HH:mm:ss";


    /**
     * 日期格式,年月日时分秒毫秒,例如:20001230120000123,20080808200808456
     */
    public static final String DATE_TIME_FORMAT_YYYYMMDDHHMISSSSS = "yyyyMMddHHmmssSSS";


    // ==特殊格式==
    /**
     * 日期格式,月日时分,例如:10-05 12:00
     */
    public static final String DATE_FORMAT_MMDDHHMI = "MM-dd HH:mm";


    /* ************工具方法***************   */

    /**
     * 获取某日期的年份
     * @param date
     * @return
     */
    public static Integer getYear(Date date) {
        Calendar cal = Calendar.getInstance();
        cal.setTime(date);
        return cal.get(Calendar.YEAR);
    }

    /**
     * 获取某日期的月份
     * @param date
     * @return
     */
    public static Integer getMonth(Date date) {
        Calendar cal = Calendar.getInstance();
        cal.setTime(date);
        return cal.get(Calendar.MONTH) + 1;
    }

    /**
     * 获取某日期的日数
     * @param date
     * @return
     */
    public static Integer getDay(Date date){
        Calendar cal = Calendar.getInstance();
        cal.setTime(date);
        int day=cal.get(Calendar.DATE);//获取日
        return day;
    }

    /**
     * 格式化Date时间
     * @param time Date类型时间
     * @param timeFromat String类型格式
     * @return 格式化后的字符串
     */
    public static String parseDate2Str(Date time, String timeFromat){
        DateFormat dateFormat=new SimpleDateFormat(timeFromat);
        return dateFormat.format(time);
    }

    /**
     * 格式化Timestamp时间
     * @param timestamp Timestamp类型时间
     * @param timeFromat
     * @return 格式化后的字符串
     */
    public static String parseTimestamp2Str(Timestamp timestamp,String timeFromat){
        SimpleDateFormat df = new SimpleDateFormat(timeFromat);
        return df.format(timestamp);
    }

    /**
     * 格式化Date时间
     * @param time Date类型时间
     * @param timeFromat String类型格式
     * @param defaultValue 默认值为当前时间Date
     * @return 格式化后的字符串
     */
    public static String parseDate2Str(Date time, String timeFromat, final Date defaultValue){
        try{
            DateFormat dateFormat=new SimpleDateFormat(timeFromat);
            return dateFormat.format(time);
        }catch (Exception e){
            if(defaultValue!=null)
                return parseDate2Str(defaultValue, timeFromat);
            else
                return parseDate2Str(new Date(), timeFromat);
        }
    }

    /**
     * 格式化Date时间
     * @param time Date类型时间
     * @param timeFromat String类型格式
     * @param defaultValue 默认时间值String类型
     * @return 格式化后的字符串
     */
    public static String parseDate2Str(Date time, String timeFromat, final String defaultValue){
        try{
            DateFormat dateFormat=new SimpleDateFormat(timeFromat);
            return dateFormat.format(time);
        }catch (Exception e){
            return defaultValue;
        }
    }

    /**
     * 格式化String时间
     * @param time String类型时间
     * @param timeFromat String类型格式
     * @return 格式化后的Date日期
     */
    public static Date parseStr2Date(String time, String timeFromat) {
        if (time == null || time.equals("")) {
            return null;
        }

        Date date=null;
        try{
            DateFormat dateFormat=new SimpleDateFormat(timeFromat);
            date=dateFormat.parse(time);
        }catch(Exception e){

        }
        return date;
    }

    /**
     * 格式化String时间
     * @param strTime String类型时间
     * @param timeFromat String类型格式
     * @param defaultValue 异常时返回的默认值
     * @return
     */
    public static Date parseStr2Date(String strTime, String timeFromat,
                                      Date defaultValue) {
        try {
            DateFormat dateFormat = new SimpleDateFormat(timeFromat);
            return dateFormat.parse(strTime);
        } catch (Exception e) {
            return defaultValue;
        }
    }

    /**
     * 当strTime为2008-9时返回为2008-9-1 00:00格式日期时间,无法转换返回null.
     * @param strTime
     * @return
     */
    public static Date str2Date(String strTime) {
        if(strTime==null || strTime.trim().length()<=0)
            return null;

        Date date = null;
        List<String> list = new ArrayList<String>(0);

        list.add(DATE_TIME_FORMAT_YYYY_MM_DD_HH_MI_SS);
        list.add(DATE_TIME_FORMAT_YYYYMMDDHHMISSSSS);
        list.add(DATE_TIME_FORMAT_YYYY_MM_DD_HH_MI);
        list.add(DATE_TIME_FORMAT_YYYYMMDD_HH_MI);
        list.add(DATE_TIME_FORMAT_YYYYMMDDHHMISS);
        list.add(DATE_FORMAT_YYYY_MM_DD);
        //list.add(DATE_FORMAT_YY_MM_DD);
        list.add(DATE_FORMAT_YYYYMMDD);
        list.add(DATE_FORMAT_YYYY_MM);
        list.add(DATE_FORMAT_YYYYMM);
        list.add(DATE_FORMAT_YYYY);


        for (Iterator iter = list.iterator(); iter.hasNext();) {
            String format = (String) iter.next();
            if(strTime.indexOf("-")>0 && format.indexOf("-")<0)
                continue;
            if(strTime.indexOf("-")<0 && format.indexOf("-")>0)
                continue;
            if(strTime.length()>format.length())
                continue;
            date = parseStr2Date(strTime, format);
            if (date != null)
                break;
        }

        return date;
    }

    /**
     * 解析两个日期之间的所有月份
     * @param beginDateStr 开始日期,至少精确到yyyy-MM
     * @param endDateStr 结束日期,至少精确到yyyy-MM
     * @return yyyy-MM日期集合
     */
    public static List<String> getMonthListOfDate(String beginDateStr, String endDateStr) {
        // 指定要解析的时间格式
        SimpleDateFormat f = new SimpleDateFormat("yyyy-MM");
        // 返回的月份列表
        String sRet = "";

        // 定义一些变量
        Date beginDate = null;
        Date endDate = null;

        GregorianCalendar beginGC = null;
        GregorianCalendar endGC = null;
        List<String> list = new ArrayList<String>();

        try {
            // 将字符串parse成日期
            beginDate = f.parse(beginDateStr);
            endDate = f.parse(endDateStr);

            // 设置日历
            beginGC = new GregorianCalendar();
            beginGC.setTime(beginDate);

            endGC = new GregorianCalendar();
            endGC.setTime(endDate);

            // 直到两个时间相同
            while (beginGC.getTime().compareTo(endGC.getTime()) <= 0) {
                sRet = beginGC.get(Calendar.YEAR) + "-"
                        + (beginGC.get(Calendar.MONTH) + 1);
                list.add(sRet);
                // 以月为单位,增加时间
                beginGC.add(Calendar.MONTH, 1);
            }
            return list;
        } catch (Exception e) {
            e.printStackTrace();
            return null;
        }
    }

    /**
     * 解析两个日期段之间的所有日期
     * @param beginDateStr 开始日期  ,至少精确到yyyy-MM-dd
     * @param endDateStr 结束日期  ,至少精确到yyyy-MM-dd
     * @return yyyy-MM-dd日期集合
     */
    public static List<String> getDayListOfDate(String beginDateStr, String endDateStr) {
        // 指定要解析的时间格式
        SimpleDateFormat f = new SimpleDateFormat("yyyy-MM-dd");

        // 定义一些变量
        Date beginDate = null;
        Date endDate = null;

        Calendar beginGC = null;
        Calendar endGC = null;
        List<String> list = new ArrayList<String>();

        try {
            // 将字符串parse成日期
            beginDate = f.parse(beginDateStr);
            endDate = f.parse(endDateStr);

            // 设置日历
            beginGC = Calendar.getInstance();
            beginGC.setTime(beginDate);

            endGC = Calendar.getInstance();
            endGC.setTime(endDate);
            SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd");

            // 直到两个时间相同
            while (beginGC.getTime().compareTo(endGC.getTime()) <= 0) {

                list.add(sdf.format(beginGC.getTime()));
                // 以日为单位,增加时间
                beginGC.add(Calendar.DAY_OF_MONTH, 1);
            }
            return list;
        } catch (Exception e) {
            e.printStackTrace();
            return null;
        }
    }

    /**
     * 获取当下年份指定前后数量的年份集合
     * @param before 当下年份前年数
     * @param behind 当下年份后年数
     * @return 集合
     */
    public static List<Integer> getYearListOfYears(int before,int behind) {
        if (before<0 || behind<0) {
            return null;
        }
        List<Integer> list = new ArrayList<Integer>();
        Calendar c = null;
        c = Calendar.getInstance();
        c.setTime(new Date());
        int currYear = Calendar.getInstance().get(Calendar.YEAR);

        int startYear = currYear - before;
        int endYear = currYear + behind;
        for (int i = startYear; i < endYear; i++) {
            list.add(Integer.valueOf(i));
        }
        return list;
    }

    /**
     * 获取当前日期是一年中第几周
     * @param date
     * @return
     */
    public static Integer getWeekthOfYear(Date date) {
        Calendar c = new GregorianCalendar();
        c.setFirstDayOfWeek(Calendar.MONDAY);
        c.setMinimalDaysInFirstWeek(7);
        c.setTime(date);

        return c.get(Calendar.WEEK_OF_YEAR);
    }

    /**
     * 获取某一年各星期的始终时间
     * 实例:getWeekList(2016),第52周(从2016-12-26至2017-01-01)
     * @param year
     * @return
     */
    public static HashMap<Integer,String> getWeekTimeOfYear(int year) {
        HashMap<Integer,String> map = new LinkedHashMap<Integer,String>();
        Calendar c = new GregorianCalendar();
        c.set(year, Calendar.DECEMBER, 31, 23, 59, 59);
        int count = getWeekthOfYear(c.getTime());

        SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd");
        String dayOfWeekStart = "";
        String dayOfWeekEnd = "";
        for (int i = 1; i <= count; i++) {
            dayOfWeekStart = sdf.format(getFirstDayOfWeek(year, i));
            dayOfWeekEnd = sdf.format(getLastDayOfWeek(year, i));
            map.put(Integer.valueOf(i), "第"+i+"周(从"+dayOfWeekStart + "至" + dayOfWeekEnd+")");
        }
        return map;

    }

    /**
     * 获取某一年的总周数
     * @param year
     * @return
     */
    public static Integer getWeekCountOfYear(int year){
        Calendar c = new GregorianCalendar();
        c.set(year, Calendar.DECEMBER, 31, 23, 59, 59);
        int count = getWeekthOfYear(c.getTime());
        return count;
    }

    /**
     * 获取指定日期所在周的第一天
     * @param date
     * @return
     */
    public static Date getFirstDayOfWeek(Date date) {
        Calendar c = new GregorianCalendar();
        c.setFirstDayOfWeek(Calendar.MONDAY);
        c.setTime(date);
        c.set(Calendar.DAY_OF_WEEK, c.getFirstDayOfWeek()); // Monday
        return c.getTime();
    }

    /**
     * 获取指定日期所在周的最后一天
     * @param date
     * @return
     */
    public static Date getLastDayOfWeek(Date date) {
        Calendar c = new GregorianCalendar();
        c.setFirstDayOfWeek(Calendar.MONDAY);
        c.setTime(date);
        c.set(Calendar.DAY_OF_WEEK, c.getFirstDayOfWeek() + 6); // Sunday
        return c.getTime();
    }

    /**
     * 获取某年某周的第一天
     * @param year 目标年份
     * @param week 目标周数
     * @return
     */
    public static Date getFirstDayOfWeek(int year, int week) {
        Calendar c = new GregorianCalendar();
        c.set(Calendar.YEAR, year);
        c.set(Calendar.MONTH, Calendar.JANUARY);
        c.set(Calendar.DATE, 1);

        Calendar cal = (GregorianCalendar) c.clone();
        cal.add(Calendar.DATE, week * 7);

        return getFirstDayOfWeek(cal.getTime());
    }

    /**
     * 获取某年某周的最后一天
     * @param year 目标年份
     * @param week 目标周数
     * @return
     */
    public static Date getLastDayOfWeek(int year, int week) {
        Calendar c = new GregorianCalendar();
        c.set(Calendar.YEAR, year);
        c.set(Calendar.MONTH, Calendar.JANUARY);
        c.set(Calendar.DATE, 1);

        Calendar cal = (GregorianCalendar) c.clone();
        cal.add(Calendar.DATE, week * 7);

        return getLastDayOfWeek(cal.getTime());
    }

    /**
     * 获取某年某月的第一天
     * @param year 目标年份
     * @param month 目标月份
     * @return
     */
    public static Date getFirstDayOfMonth(int year,int month){
        month = month-1;
        Calendar   c   =   Calendar.getInstance();
        c.set(Calendar.YEAR, year);
        c.set(Calendar.MONTH, month);

        int day = c.getActualMinimum(c.DAY_OF_MONTH);

        c.set(Calendar.DAY_OF_MONTH, day);
        c.set(Calendar.HOUR_OF_DAY, 0);
        c.set(Calendar.MINUTE, 0);
        c.set(Calendar.SECOND, 0);
        c.set(Calendar.MILLISECOND, 0);
        return c.getTime();
    }

    /**
     * 获取某年某月的最后一天
     * @param year 目标年份
     * @param month 目标月份
     * @return
     */
    public static Date getLastDayOfMonth(int year,int month){
        month = month-1;
        Calendar   c   =   Calendar.getInstance();
        c.set(Calendar.YEAR, year);
        c.set(Calendar.MONTH, month);
        int day = c.getActualMaximum(Calendar.DAY_OF_MONTH);
        c.set(Calendar.DAY_OF_MONTH, day);
        c.set(Calendar.HOUR_OF_DAY, 23);
        c.set(Calendar.MINUTE, 59);
        c.set(Calendar.SECOND, 59);
        c.set(Calendar.MILLISECOND, 999);
        return c.getTime();
    }

    /**
     * 获取某个日期为星期几
     * @param date
     * @return String "星期*"
     */
    public static String getDayWeekOfDate1(Date date) {
        String[] weekDays = {"星期日", "星期一", "星期二", "星期三", "星期四", "星期五", "星期六"};
        Calendar cal = Calendar.getInstance();
        cal.setTime(date);

        int w = cal.get(Calendar.DAY_OF_WEEK) - 1;
        if (w < 0)
            w = 0;

        return weekDays[w];
    }

    /**
     * 获得指定日期的星期几数
     * @param date
     * @return int
     */
    public static Integer getDayWeekOfDate2(Date date){
        Calendar aCalendar = Calendar.getInstance();
        aCalendar.setTime(date);
        int weekDay = aCalendar.get(Calendar.DAY_OF_WEEK);
        return weekDay;
    }

    /**
     * 验证字符串是否为日期
     * 验证格式:YYYYMMDD、YYYY_MM_DD、YYYYMMDDHHMISS、YYYYMMDD_HH_MI、YYYY_MM_DD_HH_MI、YYYYMMDDHHMISSSSS、YYYY_MM_DD_HH_MI_SS
     * @param strTime
     * @return null时返回false;true为日期,false不为日期
     */
    public static boolean validateIsDate(String strTime) {
        if (strTime == null || strTime.trim().length() <= 0)
            return false;

        Date date = null;
        List<String> list = new ArrayList<String>(0);

        list.add(DATE_TIME_FORMAT_YYYY_MM_DD_HH_MI_SS);
        list.add(DATE_TIME_FORMAT_YYYYMMDDHHMISSSSS);
        list.add(DATE_TIME_FORMAT_YYYY_MM_DD_HH_MI);
        list.add(DATE_TIME_FORMAT_YYYYMMDD_HH_MI);
        list.add(DATE_TIME_FORMAT_YYYYMMDDHHMISS);
        list.add(DATE_FORMAT_YYYY_MM_DD);
        //list.add(DATE_FORMAT_YY_MM_DD);
        list.add(DATE_FORMAT_YYYYMMDD);
        //list.add(DATE_FORMAT_YYYY_MM);
        //list.add(DATE_FORMAT_YYYYMM);
        //list.add(DATE_FORMAT_YYYY);

        for (Iterator iter = list.iterator(); iter.hasNext();) {
            String format = (String) iter.next();
            if(strTime.indexOf("-")>0 && format.indexOf("-")<0)
                continue;
            if(strTime.indexOf("-")<0 && format.indexOf("-")>0)
                continue;
            if(strTime.length()>format.length())
                continue;
            date = parseStr2Date(strTime.trim(), format);
            if (date != null)
                break;
        }

        if (date != null) {
            System.out.println("生成的日期:"+DateUtil.parseDate2Str(date, DateUtil.DATE_TIME_FORMAT_YYYY_MM_DD_HH_MI_SS, "--null--"));
            return true;
        }
        return false;
    }

    /**
     * 将指定日期的时分秒格式为零
     * @param date
     * @return
     */
    public static Date formatHhMmSsOfDate(Date date) {
        Calendar cal = Calendar.getInstance();
        cal.setTime(date);
        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();
    }

    /**
     * 获得指定时间加减参数后的日期(不计算则输入0)
     * @param date 指定日期
     * @param year 年数,可正可负
     * @param month 月数,可正可负
     * @param day 天数,可正可负
     * @param hour 小时数,可正可负
     * @param minute 分钟数,可正可负
     * @param second 秒数,可正可负
     * @param millisecond 毫秒数,可正可负
     * @return 计算后的日期
     */
    public static Date addDate(Date date,int year,int month,int day,int hour,int minute,int second,int millisecond){
        Calendar c = Calendar.getInstance();
        c.setTime(date);
        c.add(Calendar.YEAR, year);//加减年数
        c.add(Calendar.MONTH, month);//加减月数
        c.add(Calendar.DATE, day);//加减天数
        c.add(Calendar.HOUR,hour);//加减小时数
        c.add(Calendar.MINUTE, minute);//加减分钟数
        c.add(Calendar.SECOND, second);//加减秒
        c.add(Calendar.MILLISECOND, millisecond);//加减毫秒数

        return c.getTime();
    }

    /**
     * 获得两个日期的时间戳之差
     * @param startDate
     * @param endDate
     * @return
     */
    public static Long getDistanceTimestamp(Date startDate,Date endDate){
        long daysBetween=(endDate.getTime()-startDate.getTime()+1000000)/(3600*24*1000);
        return daysBetween;
    }

    /**
     * 判断二个时间是否为同年同月
     * @param date1
     * @param date2
     * @return
     */
    public static Boolean compareIsSameMonth(Date date1,Date date2){
        boolean flag = false;
        int year1  = getYear(date1);
        int year2 = getYear(date2);
        if(year1 == year2){
            int month1 = getMonth(date1);
            int month2 = getMonth(date2);
            if(month1 == month2)flag = true;
        }
        return flag;
    }

    /**
     * 获得两个时间相差距离多少天多少小时多少分多少秒
     * @param one 时间参数 1 格式:1990-01-01 12:00:00
     * @param two 时间参数 2 格式:2009-01-01 12:00:00
     * @return long[] 返回值为:{天, 时, 分, 秒}
     */
    public static long[] getDistanceTime(Date one, Date two) {
        long day = 0;
        long hour = 0;
        long min = 0;
        long sec = 0;
        try {

            long time1 = one.getTime();
            long time2 = two.getTime();
            long diff ;
            if(time1<time2) {
                diff = time2 - time1;
            } else {
                diff = time1 - time2;
            }
            day = diff / (24 * 60 * 60 * 1000);
            hour = (diff / (60 * 60 * 1000) - day * 24);
            min = ((diff / (60 * 1000)) - day * 24 * 60 - hour * 60);
            sec = (diff/1000-day*24*60*60-hour*60*60-min*60);
        } catch (Exception e) {
            e.printStackTrace();
        }
        long[] times = {day, hour, min, sec};
        return times;
    }

    /**
     * 两个时间相差距离多少天多少小时多少分多少秒
     * @param str1 时间参数 1 格式:1990-01-01 12:00:00
     * @param str2 时间参数 2 格式:2009-01-01 12:00:00
     * @return String 返回值为:{天, 时, 分, 秒}
     */
    public static long[] getDistanceTime(String str1, String str2) {
        DateFormat df = new SimpleDateFormat(DATE_TIME_FORMAT_YYYY_MM_DD_HH_MI_SS);
        Date one;
        Date two;
        long day = 0;
        long hour = 0;
        long min = 0;
        long sec = 0;
        try {
            one = df.parse(str1);
            two = df.parse(str2);
            long time1 = one.getTime();
            long time2 = two.getTime();
            long diff ;
            if(time1<time2) {
                diff = time2 - time1;
            } else {
                diff = time1 - time2;
            }
            day = diff / (24 * 60 * 60 * 1000);
            hour = (diff / (60 * 60 * 1000) - day * 24);
            min = ((diff / (60 * 1000)) - day * 24 * 60 - hour * 60);
            sec = (diff/1000-day*24*60*60-hour*60*60-min*60);
        } catch (ParseException e) {
            e.printStackTrace();
        }
        long[] times = {day, hour, min, sec};
        return times;
    }

    /**
     * 两个时间之间相差距离多少天
     * @param str1 时间参数 1:
     * @param str2 时间参数 2:
     * @return 相差天数
     */
    public static Long getDistanceDays(String str1, String str2) throws Exception{
        DateFormat df = new SimpleDateFormat(DATE_TIME_FORMAT_YYYY_MM_DD_HH_MI_SS);
        Date one;
        Date two;
        long days=0;
        try {
            one = df.parse(str1);
            two = df.parse(str2);
            long time1 = one.getTime();
            long time2 = two.getTime();
            long diff ;
            if(time1<time2) {
                diff = time2 - time1;
            } else {
                diff = time1 - time2;
            }
            days = diff / (1000 * 60 * 60 * 24);
        } catch (ParseException e) {
            e.printStackTrace();
        }
        return days;
    }

    /**
     * 获取指定时间的那天 00:00:00.000 的时间
     * @param date
     * @return
     */
    public static Date getDayBeginTime(final Date date) {
        Calendar c = Calendar.getInstance();
        c.setTime(date);
        c.set(Calendar.HOUR_OF_DAY, 0);
        c.set(Calendar.MINUTE, 0);
        c.set(Calendar.SECOND, 0);
        c.set(Calendar.MILLISECOND, 0);
        return c.getTime();
    }

    /**
     * 获取指定时间的那天 23:59:59.999 的时间
     * @param date
     * @return
     */
    public static Date getDayEndTime(final Date date) {
        Calendar c = Calendar.getInstance();
        c.setTime(date);
        c.set(Calendar.HOUR_OF_DAY, 23);
        c.set(Calendar.MINUTE, 59);
        c.set(Calendar.SECOND, 59);
        c.set(Calendar.MILLISECOND, 999);
        return c.getTime();
    }

}
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