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Java Language Использование различных классов API Date Time


Следующий пример также содержит объяснение, необходимое для понимания примера внутри него.

import java.time.Clock;
import java.time.Duration;
import java.time.Instant;
import java.time.LocalDate;
import java.time.LocalDateTime;
import java.time.LocalTime;
import java.time.ZoneId;
import java.time.ZonedDateTime;
import java.util.TimeZone;
public class SomeMethodsExamples {

 * Has the methods of the class {@link LocalDateTime}
public static void checkLocalDateTime() {
    LocalDateTime localDateTime = LocalDateTime.now();
    System.out.println("Local Date time using static now() method ::: >>> "
            + localDateTime);

    LocalDateTime ldt1 = LocalDateTime.now(ZoneId.of(ZoneId.SHORT_IDS
            .println("LOCAL TIME USING now(ZoneId zoneId) method ::: >>>>"
                    + ldt1);

    LocalDateTime ldt2 = LocalDateTime.now(Clock.system(ZoneId
            .println("Local TIME USING now(Clock.system(ZoneId.of())) ::: >>>> "
                    + ldt2);

            .println("Following is a static map in ZoneId class which has mapping of short timezone names to their Actual timezone names");


 * This has the methods of the class {@link LocalDate}
public static void checkLocalDate() {
    LocalDate localDate = LocalDate.now();
    System.out.println("Gives date without Time using now() method. >> "
            + localDate);
    LocalDate localDate2 = LocalDate.now(ZoneId.of(ZoneId.SHORT_IDS
            .println("now() is overridden to take ZoneID as parametere using this we can get the same date under different timezones. >> "
                    + localDate2);

 * This has the methods of abstract class {@link Clock}. Clock can be used
 * for time which has time with {@link TimeZone}.
public static void checkClock() {
    Clock clock = Clock.systemUTC();
    // Represents time according to ISO 8601
    System.out.println("Time using Clock class : " + clock.instant());

 * This has the {@link Instant} class methods.
public static void checkInstant() {
    Instant instant = Instant.now();

    System.out.println("Instant using now() method :: " + instant);

    Instant ins1 = Instant.now(Clock.systemUTC());

    System.out.println("Instants using now(Clock clock) :: " + ins1);


 * This class checks the methods of the {@link Duration} class.
public static void checkDuration() {
    // toString() converts the duration to PTnHnMnS format according to ISO
    // 8601 standard. If a field is zero its ignored.

    // P is the duration designator (historically called "period") placed at
    // the start of the duration representation.
    // Y is the year designator that follows the value for the number of
    // years.
    // M is the month designator that follows the value for the number of
    // months.
    // W is the week designator that follows the value for the number of
    // weeks.
    // D is the day designator that follows the value for the number of
    // days.
    // T is the time designator that precedes the time components of the
    // representation.
    // H is the hour designator that follows the value for the number of
    // hours.
    // M is the minute designator that follows the value for the number of
    // minutes.
    // S is the second designator that follows the value for the number of
    // seconds.


 * Shows Local time without date. It doesn't store or represenet a date and
 * time. Instead its a representation of Time like clock on the wall.
public static void checkLocalTime() {
    LocalTime localTime = LocalTime.now();
    System.out.println("LocalTime :: " + localTime);

 * A date time with Time zone details in ISO-8601 standards.
public static void checkZonedDateTime() {
    ZonedDateTime zonedDateTime = ZonedDateTime.now(ZoneId