按几分钟比较日历时间

Question

我想计算" 17:00"one_answers"星期二5:00"之间的差异。如何使用Java实现此目标。我不太了解如何使用日历，而SimpleDateFormat不支持MON，TUE，WED，E.T.C功能。有帮助吗？

这个问题仅涉及一周，因此最早的"太阳00:00"one_answers"星期六23:59"为最新。

P.S。鉴于许多格式的字符串，我也想将它们从首先发生的事情分类为最后发生的事情。因为我认为首先对它们进行排序会使任务（确定差异）更容易。

Answer 1

可能是这样的东西

import java.text.SimpleDateFormat;
import java.util.Locale;
import java.util.concurrent.TimeUnit;
public class DateCompare {
    public static void main(String[] args) {
        try {
            final String start = "Mon 17:00";
            final String end = "Tue 5:00";
            SimpleDateFormat formatter = new SimpleDateFormat("EEE HH:mm", Locale.US);
            long diffMinutes = TimeUnit.MILLISECONDS.toMinutes(formatter.parse(end).getTime() - formatter.parse(start).getTime()); 
            System.out.println(diffMinutes + " minutes");
        } catch(Exception ex) {
            ex.printStackTrace();
        }
    }
}

Answer 2

java没有代表一周的时间（一天中的一天和时间）的类型。我建议：

• 使用Java.Time，现代Java日期和时间API。
• 设计一个代表您的时间的课程。
• 在您的班上，在您决定的一周内，您的时间仅表示您的时间作为特定的日期和时间。这将使您免费分钟分钟和差异。

您的班级看起来像这样：

/** A time of week like "MON 17:00". In other words a day of week and time of day. */
public class TimeOfWeek implements Comparable<TimeOfWeek> {
    private static DateTimeFormatter dayTimeFormatter = new DateTimeFormatterBuilder()
            .parseCaseInsensitive()
            .appendPattern("EEE H:mm")
            .toFormatter(Locale.ENGLISH);
    /** First day of the week used internally for date-times, Sun Dec 28, 1969 */
    private static LocalDate firstDate 
            = LocalDate.EPOCH.with(TemporalAdjusters.previousOrSame(DayOfWeek.SUNDAY));
    /**
     * Internal representation;
     * always within the week of the epoch, Sun Dec 28, 1969 through Sat Jan 3, 1970.
     */
    private LocalDateTime dateTime;
    public TimeOfWeek(String dayTimeString) {
        TemporalAccessor parsed = dayTimeFormatter.parse(dayTimeString);
        DayOfWeek dow = DayOfWeek.from(parsed);
        LocalTime time = LocalTime.from(parsed);
        dateTime = firstDate.with(TemporalAdjusters.nextOrSame(dow)).atTime(time);
        assert ! dateTime.isBefore(firstDate.atStartOfDay()) : dateTime;
        assert dateTime.isBefore(firstDate.plusWeeks(1).atStartOfDay()) : dateTime;
    }
    /** The order is by day of week, Sunday first, then by time of day. */
    @Override
    public int compareTo(TimeOfWeek other) {
        return this.dateTime.compareTo(other.dateTime);
    }
    /** @return The difference in minutes between this and other (signed) */
    int minutesUntil(TimeOfWeek other) {
        return Math.toIntExact(ChronoUnit.MINUTES.between(this.dateTime, other.dateTime));
    }
    @Override
    public String toString() {
        return dateTime.format(dayTimeFormatter);
    }
}

现在对TimeOfWeek对象的列表进行排序：

    List<TimeOfWeek> dayTimes = Arrays.asList(new TimeOfWeek("Tue 5:00"),
            new TimeOfWeek("SAT 23:59"),
            new TimeOfWeek("SUN 00:00"),
            new TimeOfWeek("MON 17:00"));
    dayTimes.sort(Comparator.naturalOrder());
    System.out.println(dayTimes);

输出：

[太阳0:00，星期一17:00，星期二5:00，星期六23:59]

在排序列表中找到对象之间的成对差异：

    for (int i = 1; i < dayTimes.size(); i++) {
        TimeOfWeek start = dayTimes.get(i - 1);
        TimeOfWeek end = dayTimes.get(i);
        System.out.println("Difference between " + start + " and " + end + ": "
                + start.minutesUntil(end) + " minutes");
    }

Difference between Sun 0:00 and Mon 17:00: 2460 minutes
Difference between Mon 17:00 and Tue 5:00: 720 minutes
Difference between Tue 5:00 and Sat 23:59: 6899 minutes

链接： oracle教程：日期时间说明如何使用java.time。

Answer 3

如果不允许使用SimpleDateFormat，则最好使用Apache Lang 3。

import java.util.Arrays;
import java.util.Collections;
import java.util.Date;
import java.util.List;
import java.util.Locale;
import java.util.concurrent.TimeUnit;
import org.apache.commons.lang3.time.DateUtils;
public class DateCompare {
    public static void main(String[] args) {
        try {
            final String start = "MON 17:00";
            final String end = "Tue 5:00";
            List<Date> dates = Arrays.asList(DateUtils.parseDate(start, Locale.US, "EEE HH:mm"), DateUtils.parseDate(end, Locale.US, "EEE HH:mm"));
            Collections.sort(dates);
            long diffMinutes = TimeUnit.MILLISECONDS.toMinutes(dates.get(1).getTime() - dates.get(0).getTime()); 
            System.out.println(diffMinutes + " minutes");
        } catch(Exception ex) {
            ex.printStackTrace();
        }
    }
}