Java java.time API
Date and time features in Java is primarily supported by two packages :
java.util
java.time
The package java.time was added with the release of Java 8 with the aim of solving problems faced by Java developers while handling date and time with java.util package such as representing a date without time, etc.
Classes of Java.time :
Clock class:
This class provides access to the current instant, date and time zone using a time-zone.
Clock class is an abstract class therefore it is not possible to create instance of the clock class.
Some methods of the clock class :
abstract ZoneId getZone() : This methods returns the time zone being used to create date and time objects.
Example :
import java.time.*;
public class CWH extends Thread{
public static void main(String[] args) {
Clock cl = Clock.systemDefaultZone();
System.out.println(cl.getZone());
}
}Output
Asia/Calcutta
abstract Instant instant() :
This methods returns the current instant of the clocks.Example :
import java.time.*;
public class CWH extends Thread{
public static void main(String[] args) {
Clock cl = Clock.systemUTC();
System.out.println(cl.instant());
}
}Output
2021-05-26T06:43:05.064640700Z
Duration class :
This class is used to measure time in seconds and nano seconds.
This class is immutable.
Some Methods of the duration class :
boolean isNegative() : This method is used to check if the duration is negative.
Example :
import java.time.*;
public class CWH extends Thread{
public static void main(String[] args) {
Duration d1 = Duration.between(LocalTime.MIN,LocalTime.NOON); //LocalTime.MIN = '00:00' , LocalTime.NOON = '12:00'
System.out.println(d1.isNegative());
Duration d2 = Duration.between(LocalTime.MAX,LocalTime.MIN); //LocalTime.MAX = '23:59:59.999999999' , LocalTime.MIN = '00:00'
System.out.println(d2.isNegative());
}
}Output
false
true
true
isZero() :
This method is used to check if the duration is zero. Returns boolean value.Example :
import java.time.*;
public class CWH extends Thread{
public static void main(String[] args) {
Duration d1 = Duration.between(LocalTime.MIN,LocalTime.MIDNIGHT); //LocalTime.MIN = '00:00' , LocalTime.NOON = '00:00'
System.out.println(d1.isZero());
Duration d2 = Duration.between(LocalTime.MAX,LocalTime.MIN); //LocalTime.MAX = '23:59:59.999999999' , LocalTime.MIN = '00:00'
System.out.println(d2.isZero());
}
}Output
true
false
false
3. LocalDate class :
This class is useful for representing the dates in the year-month-day format.
With the help of LocalDate class, dates can be represented without time.
Example :
import java.time.*;
public class CWH extends Thread{
public static void main(String[] args) {
LocalDate d = LocalDate.now();
System.out.println(d);
}
}
Output
2021-05-26
Some methods of the LocalDate class :
compareTo() :
This method compares the equality of the two dates. Returns boolean value.Example :
import java.time.*;
public class CWH extends Thread{
public static void main(String[] args) {
LocalDate d = LocalDate.parse("2021-05-27");
LocalDate d1= LocalDate.parse("2021-05-26");
LocalDate d2= LocalDate.parse("2021-05-26");
System.out.println(d1.equals(d));
System.out.println(d2.equals(d1));
}
}
Output
false
true
true
withYear(int Year) :
This method returns a copy of the LocaleDate but alters the year with the value of year passed as argument.Example :
import java.time.*;
public class CWH extends Thread{
public static void main(String[] args) {
LocalDate d = LocalDate.parse("2021-05-27");
System.out.println(d.withYear(2001));
}
}
Output
2001-05-27
4. LocalTime class :
This class helps us to represent the time without the dates.
Instances of LocalTime class are mutable.
Example :
import java.time.*;
public class CWH extends Thread{
public static void main(String[] args) {
LocalTime t = LocalTime.now();
System.out.println(t);
}
}
Output
13:13:36.198479100
Some methods of the LocalTime class :
LocalTime plusHours(long hoursToAdd) :
This method returns a copy of the LocalTime but with the specified number of hours added.Example :
import java.time.*;
public class CWH extends Thread{
public static void main(String[] args) {
LocalTime t = LocalTime.of(15,28,19);
System.out.println("Time before : " + t);
LocalTime t1= t.minusMinutes(8);
System.out.println("Time after subtracting 8 minutes : " + t1);
}
}
Output
Time before : 15:28:19
Time after subtracting 8 minutes : 15:20:19
Time after subtracting 8 minutes : 15:20:19
Example
package com.company;
import java.time.LocalDate;
import java.time.LocalDateTime;
import java.time.LocalTime;
public class cwh_100_java_time {
public static void main(String[] args) {
LocalDate d = LocalDate.now();
System.out.println(d);
LocalTime t = LocalTime.now();
System.out.println(t);
LocalDateTime dt = LocalDateTime.now();
System.out.println(dt);
}
}