6

首先，这是我在 Java 1 课程中遇到的一个简单问题。这是一个静态时间，我已经将其设置为“今天”8:49:12，我要弄清楚午夜过后多少秒以及“到”午夜这代表了多少秒。8 小时 49 分 12 秒。这是我现在的代码：

hour    = 8;
minute  = 59;
second  = 32;
System.out.println("The static time used for this program was: " + hour + ":" + minute + ":" + second);

我的问题是我不知道如何从午夜开始获取时间。

所以基本上输出需要是：

Number of seconds since midnight: 
Number of seconds to midnight:

后面的空格是秒。

谢谢，请解释原因，以及您如何选择如何解决这个问题。我想学:P

4

7 回答 7

9

试试这个简单的数学：

System.out.println("Number of seconds since midnight:" +(second + (minute*60) + (hour*3600)));
System.out.println("Number of seconds to midnight:" +((60-second) + ((60-1-minute)*60) + (24-1-hour)*3600));
于 2013-09-24T06:55:10.533 回答
4

JAVA调用中有一个枚举TimeUnit可以将时间转换为任何时间单位，如下所示：

        int hour    = 8;
        int minute  = 59;
        int second  = 32;
        System.out.println("The static time used for this program was: " + hour + ":" + minute + ":" + second);

        long secInMidnight = TimeUnit.HOURS.toSeconds(24);
        long timeInSeconds = (TimeUnit.HOURS.toSeconds(8) + TimeUnit.MINUTES.toSeconds(minute) + second);

        System.out.println("\nSince midnight: " + timeInSeconds + "\nUntil midnight: " + (secInMidnight - timeInSeconds) );
于 2013-09-24T07:22:57.913 回答
3

鉴于时间的特殊性，您可以简单地使用CalendarAPI

Calendar fromMidnight = Calendar.getInstance();
fromMidnight.set(Calendar.HOUR, 0);
fromMidnight.set(Calendar.MINUTE, 0);
fromMidnight.set(Calendar.SECOND, 0);
fromMidnight.set(Calendar.MILLISECOND, 0);

Calendar toMidnight = Calendar.getInstance();
toMidnight.setTime(fromMidnight.getTime());
toMidnight.add(Calendar.DATE, 1);

System.out.println(fromMidnight.getTime());
System.out.println(toMidnight.getTime());

Calendar toFromTime = Calendar.getInstance();
toFromTime.set(Calendar.HOUR, 8);
toFromTime.set(Calendar.MINUTE, 59);
toFromTime.set(Calendar.SECOND, 32);
toFromTime.set(Calendar.MILLISECOND, 0);

long secondsFromMidnight = (toFromTime.getTimeInMillis() - fromMidnight.getTimeInMillis()) / 1000;
long secondsToMidnight = (toMidnight.getTimeInMillis() - toFromTime.getTimeInMillis()) / 1000;

System.out.println("from = " + secondsFromMidnight + "; to " + secondsToMidnight);

哪个输出...

from = 32372; to 54028

或者你可以使用JodaTime ...

MutableDateTime now = MutableDateTime.now();
now.setMillisOfDay(0);
now.setSecondOfDay(32);
now.setMinuteOfDay(59);
now.setHourOfDay(8);
DateTime fromMidnight = now.toDateTime().toDateMidnight().toDateTime();
DateTime toMidnight = fromMidnight.plusDays(1);

Duration duration = new Duration(fromMidnight, toMidnight);

Duration dFromMidnight = new Duration(fromMidnight, now);
System.out.println("From midnight: " + dFromMidnight.getStandardSeconds());

Duration dToMidnight = new Duration(now, toMidnight);
System.out.println("To Midnight: " + dToMidnight.getStandardSeconds());

哪个输出...

From midnight: 32372
To Midnight: 54028
于 2013-09-24T07:13:24.950 回答
3 
final static int SEC_IN_MIN = 60;
final static int SEC_IN_HOUR = SEC_IN_MIN * 60;
int secFromMidnight = hour * SEC_IN_HOUR + minute * SEC_IN_MIN + second;
int secToMidnight = (24 * SEC_IN_HOUR) - secFromMidnight;
于 2013-09-24T06:52:16.037 回答
2

由于问题的数学简单性，@Vimal Bera 的公认答案很好并且完全足够。但是，如果您仍然喜欢“形式化”（由库支持）方法而不进行“大量”计算，那么您可以在Java-8中执行此操作：

LocalTime time = LocalTime.of(8, 59, 32);
System.out.println(
  "Seconds since midnight: " 
  + time.get(ChronoField.SECOND_OF_DAY)); // 32372
System.out.println(
  "Seconds to midnight: " 
  + (86400 - time.get(ChronoField.SECOND_OF_DAY))); // 54028
于 2015-12-23T09:46:36.537 回答
0 
import java.util.Calendar;

public class HelloWorld{

 public static void main(String []args){
    int hour    = 8;
    int minute  = 59;
    int second  = 32;
    System.out.println("The static time used for this program was: " + hour + ":" + minute + ":" + second);
    final Calendar currentTime = Calendar.getInstance();
    currentTime.set(2013,Calendar.SEPTEMBER,24,8,59,32);
    final Calendar midNight = Calendar.getInstance();
    midNight.clear();
    midNight.set(2013, Calendar.SEPTEMBER, 25);
    System.out.println(.001*(midNight.getTimeInMillis() - currentTime.getTimeInMillis()));
 }

}

考虑使用Calendar和或尝试JodaTime库

http://www.joda.org/joda-time/

于 2013-09-24T07:03:58.400 回答
0

您的答案在 java.util.Calendar 类中。请参阅 get()/set() 方法： http ://docs.oracle.com/javase/6/docs/api/java/util/Calendar.html

于 2013-09-24T06:56:08.923 回答