Java Date and Time Handling

1. Introduction

Java provides robust and flexible classes for working with dates and times, introduced in Java 8 as part of the java.time package. These APIs overcome the limitations of the older Date and Calendar classes.

2. Key Date and Time Types

LocalDate

LocalDate represents a date without a time zone, such as 2024-04-01.

import java.time.LocalDate;

public class LocalDateExample {
    public static void main(String[] args) {
        LocalDate today = LocalDate.now();
        System.out.println("Today's Date: " + today);
        
        LocalDate specificDate = LocalDate.of(2024, 4, 1);
        System.out.println("Specific Date: " + specificDate);
    }
}
        

LocalTime

LocalTime represents a time without a date, such as 14:30:45.

import java.time.LocalTime;

public class LocalTimeExample {
    public static void main(String[] args) {
        LocalTime now = LocalTime.now();
        System.out.println("Current Time: " + now);
    }
}
        

Period

Period represents a quantity of time in terms of years, months, and days.

import java.time.LocalDate;
import java.time.Period;

public class PeriodExample {
    public static void main(String[] args) {
        LocalDate startDate = LocalDate.of(2023, 1, 1);
        LocalDate endDate = LocalDate.of(2024, 4, 1);
        Period period = Period.between(startDate, endDate);
        
        System.out.println("Period: " + period.getYears() + " years, " 
                          + period.getMonths() + " months, " 
                          + period.getDays() + " days");
    }
}
        

Duration

Duration measures time in terms of seconds, minutes, hours, etc.

import java.time.Duration;
import java.time.LocalTime;

public class DurationExample {
    public static void main(String[] args) {
        LocalTime startTime = LocalTime.of(14, 0);
        LocalTime endTime = LocalTime.of(16, 30);
        
        Duration duration = Duration.between(startTime, endTime);
        System.out.println("Duration: " + duration.toHours() + " hours, " 
                          + duration.toMinutesPart() + " minutes");
    }
}
        

3. Calculations with Dates and Times

Java supports calculations with LocalDate and LocalTime using methods like plusDays(), minusMonths(), and more.

import java.time.LocalDate;

public class DateCalculations {
    public static void main(String[] args) {
        LocalDate today = LocalDate.now();
        System.out.println("Today: " + today);
        
        LocalDate nextWeek = today.plusDays(7);
        System.out.println("Next Week: " + nextWeek);
        
        LocalDate lastMonth = today.minusMonths(1);
        System.out.println("Last Month: " + lastMonth);
    }
}
        

By mastering Java's date and time API, developers can write clean and precise code for handling temporal data. Next, we’ll explore localization features in Java.