Datum und Zeit

import java.time.*;
import java.time.format.*;

public class Zeit {
    public static void main(String[] args) {
        LocalDate d = LocalDate.of(2025, 3, 8);
        System.out.println(d + " " + d.getDayOfWeek() + " " + d.getMonth() + " " + d.getDayOfYear() + " " + d.isLeapYear());

        LocalDate morgen = d.plusDays(1);
        LocalDate in3Monaten = d.plusMonths(3);
        System.out.println(morgen + " " + in3Monaten + " " + d.minusWeeks(2) + " " + d.withDayOfMonth(1));

        LocalDateTime dt = LocalDateTime.of(2025, 12, 24, 18, 30);
        System.out.println(dt + " " + dt.toLocalTime() + " " + dt.getHour());
        System.out.println(d.isBefore(LocalDate.of(2025, 12, 24)) + " " + d.equals(LocalDate.parse("2025-03-08")));
    }
}

2025-03-08 SATURDAY MARCH 67 false
2025-03-09 2025-06-08 2025-02-22 2025-03-01
2025-12-24T18:30 18:30 18
true true

import java.time.*;
import java.time.temporal.ChronoUnit;

public class Spannen {
    public static void main(String[] args) {
        LocalDate start = LocalDate.of(2025, 3, 8), ende = LocalDate.of(2025, 12, 24);
        System.out.println(ChronoUnit.DAYS.between(start, ende) + " Tage");
        Period p = Period.between(LocalDate.of(2000, 5, 17), start);
        System.out.println(p.getYears() + " Jahre, " + p.getMonths() + " Monate, " + p.getDays() + " Tage");

        Duration dauer = Duration.between(LocalTime.of(9, 30), LocalTime.of(17, 45));
        System.out.println(dauer + " = " + dauer.toHours() + " h " + dauer.toMinutesPart() + " min");
        System.out.println(Duration.ofSeconds(3725).toMinutes());
    }
}

291 Tage
24 Jahre, 9 Monate, 19 Tage
PT8H15M = 8 h 15 min
62

import java.time.*;
import java.time.format.*;
import java.util.Locale;

public class Format {
    public static void main(String[] args) {
        LocalDateTime dt = LocalDateTime.of(2025, 3, 8, 14, 5);
        DateTimeFormatter f = DateTimeFormatter.ofPattern("dd.MM.yyyy HH:mm");
        System.out.println(dt.format(f));

        LocalDate d = LocalDate.parse("24.12.2025", DateTimeFormatter.ofPattern("dd.MM.yyyy"));
        System.out.println(d + " " + d.getDayOfWeek());

        DateTimeFormatter lang = DateTimeFormatter.ofPattern("EEEE, d. MMMM yyyy", Locale.GERMAN);
        System.out.println(dt.format(lang));
        System.out.println(dt.format(DateTimeFormatter.ISO_LOCAL_DATE_TIME));

        try { LocalDate.parse("31.02.2025", DateTimeFormatter.ofPattern("dd.MM.yyyy")); }
        catch (DateTimeParseException e) { System.out.println("ungültig"); }
    }
}

08.03.2025 14:05
2025-12-24 WEDNESDAY
Samstag, 8. März 2025
2025-03-08T14:05:00

import java.time.*;

public class Zonen {
    public static void main(String[] args) {
        ZonedDateTime berlin = ZonedDateTime.of(2025, 7, 1, 12, 0, 0, 0, ZoneId.of("Europe/Berlin"));
        ZonedDateTime tokio = berlin.withZoneSameInstant(ZoneId.of("Asia/Tokyo"));
        ZonedDateTime utc = berlin.withZoneSameInstant(ZoneOffset.UTC);
        System.out.println(berlin);
        System.out.println(tokio.toLocalDateTime() + " | " + utc.toLocalDateTime());

        Instant jetzt = Instant.ofEpochSecond(0);
        System.out.println(jetzt + " " + Instant.parse("2025-01-01T00:00:00Z").getEpochSecond());
    }
}

2025-07-01T12:00+02:00[Europe/Berlin]
2025-07-01T19:00 | 2025-07-01T10:00
1970-01-01T00:00:00Z 1735689600

import java.time.*;

public class Uhren {
    static String gruss(Clock uhr) {
        int h = LocalTime.now(uhr).getHour();
        return h < 12 ? "Guten Morgen" : h < 18 ? "Guten Tag" : "Guten Abend";
    }
    public static void main(String[] args) {
        Clock morgens = Clock.fixed(Instant.parse("2025-03-08T08:00:00Z"), ZoneOffset.UTC);
        Clock abends = Clock.fixed(Instant.parse("2025-03-08T20:00:00Z"), ZoneOffset.UTC);
        System.out.println(gruss(morgens) + ", " + gruss(abends));
    }
}

Guten Morgen, Guten Abend