几秒前，几分钟前，几小时前，几天前，几月前，几年前的java实现代码

import java.text.ParseException;    import java.text.SimpleDateFormat;    import java.util.Date;        public class RelativeDateFormat {            private static final long ONE_MINUTE = 60000L;        private static final long ONE_HOUR = 3600000L;        private static final long ONE_DAY = 86400000L;        private static final long ONE_WEEK = 604800000L;            private static final String ONE_SECOND_AGO = "秒前";        private static final String ONE_MINUTE_AGO = "分钟前";        private static final String ONE_HOUR_AGO = "小时前";        private static final String ONE_DAY_AGO = "天前";        private static final String ONE_MONTH_AGO = "月前";        private static final String ONE_YEAR_AGO = "年前";            public static void main(String[] args) throws ParseException {            SimpleDateFormat format = new SimpleDateFormat("yyyy-MM-dd HH:m:s");            Date date = format.parse("2013-11-11 18:35:35");            System.out.println(format(date));        }            public static String format(Date date) {            long delta = new Date().getTime() - date.getTime();            if (delta < 1L * ONE_MINUTE) {                long seconds = toSeconds(delta);                return (seconds <= 0 ? 1 : seconds) + ONE_SECOND_AGO;            }            if (delta < 45L * ONE_MINUTE) {                long minutes = toMinutes(delta);                return (minutes <= 0 ? 1 : minutes) + ONE_MINUTE_AGO;            }            if (delta < 24L * ONE_HOUR) {                long hours = toHours(delta);                return (hours <= 0 ? 1 : hours) + ONE_HOUR_AGO;            }            if (delta < 48L * ONE_HOUR) {                return "昨天";            }            if (delta < 30L * ONE_DAY) {                long days = toDays(delta);                return (days <= 0 ? 1 : days) + ONE_DAY_AGO;            }            if (delta < 12L * 4L * ONE_WEEK) {                long months = toMonths(delta);                return (months <= 0 ? 1 : months) + ONE_MONTH_AGO;            } else {                long years = toYears(delta);                return (years <= 0 ? 1 : years) + ONE_YEAR_AGO;            }        }            private static long toSeconds(long date) {            return date / 1000L;        }            private static long toMinutes(long date) {            return toSeconds(date) / 60L;        }            private static long toHours(long date) {            return toMinutes(date) / 60L;        }            private static long toDays(long date) {            return toHours(date) / 24L;        }            private static long toMonths(long date) {            return toDays(date) / 30L;        }            private static long toYears(long date) {            return toMonths(date) / 365L;        }        }