我在Scala中使用Java的Java .util.Date类,并希望比较Date对象和当前时间。我知道我可以通过使用getTime()来计算delta:

(new java.util.Date()).getTime() - oldDate.getTime()

然而,这只给我留下一个长表示毫秒。有没有更简单,更好的方法来得到时间?


当前回答

public static String getDifferenceBtwTime(Date dateTime) {

    long timeDifferenceMilliseconds = new Date().getTime() - dateTime.getTime();
    long diffSeconds = timeDifferenceMilliseconds / 1000;
    long diffMinutes = timeDifferenceMilliseconds / (60 * 1000);
    long diffHours = timeDifferenceMilliseconds / (60 * 60 * 1000);
    long diffDays = timeDifferenceMilliseconds / (60 * 60 * 1000 * 24);
    long diffWeeks = timeDifferenceMilliseconds / (60 * 60 * 1000 * 24 * 7);
    long diffMonths = (long) (timeDifferenceMilliseconds / (60 * 60 * 1000 * 24 * 30.41666666));
    long diffYears = (long)(timeDifferenceMilliseconds / (1000 * 60 * 60 * 24 * 365));

    if (diffSeconds < 1) {
        return "one sec ago";
    } else if (diffMinutes < 1) {
        return diffSeconds + " seconds ago";
    } else if (diffHours < 1) {
        return diffMinutes + " minutes ago";
    } else if (diffDays < 1) {
        return diffHours + " hours ago";
    } else if (diffWeeks < 1) {
        return diffDays + " days ago";
    } else if (diffMonths < 1) {
        return diffWeeks + " weeks ago";
    } else if (diffYears < 12) {
        return diffMonths + " months ago";
    } else {
        return diffYears + " years ago";
    }
}   

其他回答

使用GMT时区获取一个Calendar实例,使用Calendar类的set方法设置时间。GMT时区偏移量为0(并不重要),夏令时标志设置为false。

    final Calendar cal = Calendar.getInstance(TimeZone.getTimeZone("GMT"));

    cal.set(Calendar.YEAR, 2011);
    cal.set(Calendar.MONTH, 9);
    cal.set(Calendar.DAY_OF_MONTH, 29);
    cal.set(Calendar.HOUR, 0);
    cal.set(Calendar.MINUTE, 0);
    cal.set(Calendar.SECOND, 0);
    final Date startDate = cal.getTime();

    cal.set(Calendar.YEAR, 2011);
    cal.set(Calendar.MONTH, 12);
    cal.set(Calendar.DAY_OF_MONTH, 21);
    cal.set(Calendar.HOUR, 0);
    cal.set(Calendar.MINUTE, 0);
    cal.set(Calendar.SECOND, 0);
    final Date endDate = cal.getTime();

    System.out.println((endDate.getTime() - startDate.getTime()) % (1000l * 60l * 60l * 24l));

看看Joda Time,它是一个改进的Java日期/时间API,应该可以很好地与Scala一起工作。

试试这个:

int epoch = (int) (new java.text.SimpleDateFormat("MM/dd/yyyy HH:mm:ss").parse("01/01/1970  00:00:00").getTime() / 1000);

你可以在parse()方法参数中编辑字符串。

使用java。Java 8+内置的时间框架:

ZonedDateTime now = ZonedDateTime.now();
ZonedDateTime oldDate = now.minusDays(1).minusMinutes(10);
Duration duration = Duration.between(oldDate, now);
System.out.println("ISO-8601: " + duration);
System.out.println("Minutes: " + duration.toMinutes());

输出:

ISO-8601: PT24H10M 分钟:罢工,

有关更多信息,请参阅Oracle教程和ISO 8601标准。

简单的diff(不含lib)

/**
 * Get a diff between two dates
 * @param date1 the oldest date
 * @param date2 the newest date
 * @param timeUnit the unit in which you want the diff
 * @return the diff value, in the provided unit
 */
public static long getDateDiff(Date date1, Date date2, TimeUnit timeUnit) {
    long diffInMillies = date2.getTime() - date1.getTime();
    return timeUnit.convert(diffInMillies,TimeUnit.MILLISECONDS);
}

然后你可以调用:

getDateDiff(date1,date2,TimeUnit.MINUTES);

以分钟为单位获取两个日期的差值。

TimeUnit是java.util.concurrent。TimeUnit,一个从纳米到天的标准Java枚举。


人类可读的差异(不含lib)

public static Map<TimeUnit,Long> computeDiff(Date date1, Date date2) {

    long diffInMillies = date2.getTime() - date1.getTime();

    //create the list
    List<TimeUnit> units = new ArrayList<TimeUnit>(EnumSet.allOf(TimeUnit.class));
    Collections.reverse(units);

    //create the result map of TimeUnit and difference
    Map<TimeUnit,Long> result = new LinkedHashMap<TimeUnit,Long>();
    long milliesRest = diffInMillies;

    for ( TimeUnit unit : units ) {
        
        //calculate difference in millisecond 
        long diff = unit.convert(milliesRest,TimeUnit.MILLISECONDS);
        long diffInMilliesForUnit = unit.toMillis(diff);
        milliesRest = milliesRest - diffInMilliesForUnit;

        //put the result in the map
        result.put(unit,diff);
    }

    return result;
}

http://ideone.com/5dXeu6

输出类似Map:{DAYS=1, HOURS=3, MINUTES=46, SECONDS=40, MILLISECONDS=0, MICROSECONDS=0, NANOSECONDS=0},单位是有序的。

您只需将该映射转换为用户友好的字符串。


警告

上面的代码段计算两个瞬间之间的简单差。它会在夏令时切换期间导致问题,就像这篇文章中解释的那样。这意味着如果你计算没有时间的日期之间的差异,你可能会少了一天/小时。

在我看来,日期的差异是主观的,尤其是在日子上。你可以:

计算经过24小时的时间:day+1 - day = 1 day = 24h 计算经过的时间,考虑到夏令时:天+1 -天= 1 = 24小时(但使用午夜时间和夏令时,它可以是0天和23小时) 计算日开关的数量,这意味着一天+1 1pm -一天11am = 1天,即使经过的时间只有2h(如果有夏令时则为1h:p)

我的答案是有效的,如果你的日期差异的定义天匹配第一种情况

与JodaTime

如果你正在使用JodaTime,你可以得到2个瞬间的差异(millies支持ReadableInstant)日期:

Interval interval = new Interval(oldInstant, new Instant());

但是你也可以得到本地日期/时间的差异:

// returns 4 because of the leap year of 366 days
new Period(LocalDate.now(), LocalDate.now().plusDays(365*5), PeriodType.years()).getYears() 

// this time it returns 5
new Period(LocalDate.now(), LocalDate.now().plusDays(365*5+1), PeriodType.years()).getYears() 

// And you can also use these static methods
Years.yearsBetween(LocalDate.now(), LocalDate.now().plusDays(365*5)).getYears()