import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.Date;/*** 时间计算工具类*/
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";/*** 测试main 方法。 无实际引用** @param args String[]* @throws ParseException 解析异常*/public static void main(String[] args) throws ParseException {SimpleDateFormat format = new SimpleDateFormat("yyyy-MM-dd HH:m:s");Date date = format.parse("2021-05-11 18:35:35");System.out.println(format(date));}public static String format(Date date) {long delta = new Date().getTime() - date.getTime();if (delta < 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;}}