时间工具类加减时间，字符串和Date相互转换大全

左手的ㄟ右手 2023-10-04 16:52 21阅读 0赞

加减时间方法：
    /**
     * 加减时间
     * @param startDate
     * @param unit 单位
     * @param days 时间
     * @return
     */
    public static Date calcDate(Date startDate, String unit, Integer days){
        Calendar cal = Calendar.getInstance();
        //设置起时间
        cal.setTime(startDate);
        if("year".equals(unit)){
            cal.add(Calendar.YEAR, days);//增加一年
        }else if("month".equals(unit)){
            cal.add(Calendar.MONTH, days);//增加一个月   
        }else if("week".equals(unit)){
            Integer day = 7*days;
            cal.add(Calendar.DATE, day);//增加一天  
        }else if("day".equals(unit)){
            cal.add(Calendar.DATE, days);//增加一天  
        }
        return cal.getTime();
    }

计算两个时间差 天数

/**
     * 计算两个时间差 天数
     */
    public static int getDiff(Date beginDate, Date endDate) {
        long diff = (endDate.getTime() - beginDate.getTime()) / (1000 * 60 * 60 * 24);
        int days = new Long(diff).intValue();
        return days;
    }

String类型转换为Date类型, Date类型转换为String类型

/**
     * 将"2015-08-31 21:08:06"型字符串转化为Date
     *
     * @param str
     * @return
     * @throws ParseException
     */
    public static Date StringToDate(String str) throws ParseException {
        SimpleDateFormat formatter = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
        Date date = formatter.parse(str);
        return date;
    }
    
                
        /**
         * date类型进行格式化输出（返回类型：String yyyy-MM-dd HH:mm:ss）
         *
         * @param date
         * @return
         * @author tianyu.tang
         */
        public static String dateFormatDay(Date date) {
            SimpleDateFormat formatter = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
            String dateString = formatter.format(date);
            return dateString;
        }

其他方法：

/**
         * 获取当天开始时间
         *
         * @return
         */
        public static Date getDayBegin() {
            Calendar cal = Calendar.getInstance();
            cal.set(Calendar.HOUR_OF_DAY, 0);//0点
            cal.set(Calendar.MINUTE, 0);//0分
            cal.set(Calendar.SECOND, 0);//0秒
            cal.set(Calendar.MILLISECOND, 0);//0毫秒
            return cal.getTime();
        }
    
    
        /**
         * 获取当天结束时间
         *
         * @return
         */
        public static Date getDayEnd() {
            Calendar cal = Calendar.getInstance();
            cal.set(Calendar.HOUR_OF_DAY, 23);//23点
            cal.set(Calendar.MINUTE, 59);//59分
            cal.set(Calendar.SECOND, 59);//59秒
            return cal.getTime();
        }
    
    
        /**
         * 获取昨天开始时间
         *
         * @return
         */
        public static Date getBeginDayOfYesterday() {
            Calendar cal = Calendar.getInstance();
            cal.setTime(getDayBegin());//当天开始时间
            cal.add(Calendar.DAY_OF_MONTH, -1);//当天月份天数减1
            return cal.getTime();
        }
    
    
        /**
         * 获取昨天结束时间
         *
         * @return
         */
        public static Date getEndDayOfYesterday() {
            Calendar cal = Calendar.getInstance();
            cal.setTime(getDayEnd());//当天结束时间
            cal.add(Calendar.DAY_OF_MONTH, -1);//当天月份天数减1
            return cal.getTime();
        }
    
    
        /**
         * 获取明天开始时间
         *
         * @return
         */
        public static Date getBeginDayOfTomorrow() {
            Calendar cal = Calendar.getInstance();
            cal.setTime(getDayBegin());//当天开始时间
            cal.add(Calendar.DAY_OF_MONTH, 1);//当天月份天数加1
            return cal.getTime();
        }
    
    
        /**
         * 获取明天结束时间
         *
         * @return
         */
        public static Date getEndDayOfTomorrow() {
            Calendar cal = Calendar.getInstance();
            cal.setTime(getDayEnd());//当天结束时间
            cal.add(Calendar.DAY_OF_MONTH, 1);//当天月份天数加1
            return cal.getTime();
        }
    
    
        /**
         * 获取某个日期的开始时间
         *
         * @param d
         * @return
         */
        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());
        }
    
    
        /**
         * 获取某个日期的结束时间
         *
         * @param d
         * @return
         */
        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());
        }
    
    
        /**
         * 获取本周的开始时间
         *
         * @return
         */
        @SuppressWarnings("unused")
        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());
        }
    
    
        /**
         * 获取本周的结束时间
         *
         * @return
         */
        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);
        }
    
    
        /**
         * 获取上周开始时间
         */
        @SuppressWarnings("unused")
        public static Date getBeginDayOfLastWeek() {
            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 - 7);
            return getDayStartTime(cal.getTime());
        }
    
    
        /**
         * 获取上周的结束时间
         *
         * @return
         */
        public static Date getEndDayOfLastWeek() {
            Calendar cal = Calendar.getInstance();
            cal.setTime(getBeginDayOfLastWeek());
            cal.add(Calendar.DAY_OF_WEEK, 6);
            Date weekEndSta = cal.getTime();
            return getDayEndTime(weekEndSta);
        }
    
    
        /**
         * 获取今年是哪一年
         *
         * @return
         */
        public static Integer getNowYear() {
            Date date = new Date();
            GregorianCalendar gc = (GregorianCalendar) Calendar.getInstance();
            gc.setTime(date);
            return Integer.valueOf(gc.get(1));
        }
    
    
        /**
         * 获取本月是哪一月
         *
         * @return
         */
        public static int getNowMonth() {
            Date date = new Date();
            GregorianCalendar gc = (GregorianCalendar) Calendar.getInstance();
            gc.setTime(date);
            return gc.get(2) + 1;
        }
    
    
        /**
         * 获取本月的开始时间
         *
         * @return
         */
        public static Date getBeginDayOfMonth() {
            Calendar calendar = Calendar.getInstance();
            calendar.set(getNowYear(), getNowMonth() - 1, 1);
            return getDayStartTime(calendar.getTime());
        }
    
    
        /**
         * 获取本月的结束时间
         *
         * @return
         */
        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());
        }
    
    
        /**
         * 获取上月的开始时间
         *
         * @return
         */
        public static Date getBeginDayOfLastMonth() {
            Calendar calendar = Calendar.getInstance();
            calendar.set(getNowYear(), getNowMonth() - 2, 1);
            return getDayStartTime(calendar.getTime());
        }
    
    
        /**
         * 获取上月的结束时间
         *
         * @return
         */
        public static Date getEndDayOfLastMonth() {
            Calendar calendar = Calendar.getInstance();
            calendar.set(getNowYear(), getNowMonth() - 2, 1);
            int day = calendar.getActualMaximum(5);
            calendar.set(getNowYear(), getNowMonth() - 2, day);
            return getDayEndTime(calendar.getTime());
        }
    
    
        /**
         * 获取本年的开始时间
         *
         * @return
         */
        public static Date getBeginDayOfYear() {
            Calendar cal = Calendar.getInstance();
            cal.set(Calendar.YEAR, getNowYear());
            cal.set(Calendar.MONTH, Calendar.JANUARY);
            cal.set(Calendar.DATE, 1);
            return getDayStartTime(cal.getTime());
        }
    
    
        /**
         * 获取本年的结束时间
         *
         * @return
         */
        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());
        }