How do I checks if two dates are on the same day?

In this example you’ll learn how to find out if two defined date objects are on the same day. It means that we are only interested in the date information and ignoring the time information of these date objects. We’ll be using an API provided by the Apache Commons Lang in this example. So here is the code snippet:

package org.kodejava.example.commons.lang;

import org.apache.commons.lang3.time.DateUtils;

import java.util.Calendar;
import java.util.Date;

public class CheckSameDay {
    public static void main(String[] args) {
        Date date1 = new Date();
        Date date2 = new Date();

        // Checks to see if the dates is on the same day.
        if (DateUtils.isSameDay(date1, date2)) {
            System.out.printf("%1$te/%1$tm/%1$tY and %2$te/%2$tm/%2$tY " +
                    "is on the same day.%n", date1, date2);
        }

        Calendar cal1 = Calendar.getInstance();
        Calendar cal2 = Calendar.getInstance();

        // Checks to see if the calendars is on the same day.
        if (DateUtils.isSameDay(cal1, cal2)) {
            System.out.printf("%1$te/%1$tm/%1$tY and %2$te/%2$tm/%2$tY " +
                    "is on the same day.%n", cal1, cal2);
        }

        cal2.add(Calendar.DAY_OF_MONTH, 10);
        if (!DateUtils.isSameDay(cal1, cal2)) {
            System.out.printf("%1$te/%1$tm/%1$tY and %2$te/%2$tm/%2$tY " +
                    "is not on the same day.", cal1, cal2);
        }
    }
}

The example result produced by this snippet are:

24/07/2019 and 24/07/2019 is on the same day.
24/07/2019 and 24/07/2019 is on the same day.
24/07/2019 and 3/08/2019 is not on the same day.

Maven Dependencies

<!-- https://search.maven.org/remotecontent?filepath=org/apache/commons/commons-lang3/3.9/commons-lang3-3.9.jar -->
<dependency>
    <groupId>org.apache.commons</groupId>
    <artifactId>commons-lang3</artifactId>
    <version>3.9</version>
</dependency>

Maven Central

How do I get the nearest hour, minute, second of a date?

This example demonstrate how to use the DateUtils.round() method to get the nearest hour, minute and second of a date.

package org.kodejava.example.commons.lang;

import org.apache.commons.lang3.time.DateFormatUtils;
import org.apache.commons.lang3.time.DateUtils;
import org.apache.commons.lang3.time.FastDateFormat;

import java.util.Calendar;
import java.util.Date;

public class DateRoundingDemo {
    public static void main(String[] args) {
        FastDateFormat formatter = DateFormatUtils.ISO_8601_EXTENDED_DATETIME_TIME_ZONE_FORMAT;

        Date now = new Date();
        System.out.println("now = " + formatter.format(now));

        // Get nearest second
        Date nearestSecond = DateUtils.round(now, Calendar.SECOND);
        System.out.println("nearestSecond = " + formatter.format(nearestSecond));

        // Get nearest minute
        Date nearestMinute = DateUtils.round(now, Calendar.MINUTE);
        System.out.println("nearestMinute = " + formatter.format(nearestMinute));

        // Get nearest hour
        Date nearestHour = DateUtils.round(now, Calendar.HOUR);
        System.out.println("nearestHour = " + formatter.format(nearestHour));
    }
}

Here are the program results:

now = 2019-07-24T10:29:21+08:00
nearestSecond = 2019-07-24T10:29:22+08:00
nearestMinute = 2019-07-24T10:29:00+08:00
nearestHour = 2019-07-24T10:00:00+08:00

Maven Dependencies

<!-- https://search.maven.org/remotecontent?filepath=org/apache/commons/commons-lang3/3.9/commons-lang3-3.9.jar -->
<dependency>
    <groupId>org.apache.commons</groupId>
    <artifactId>commons-lang3</artifactId>
    <version>3.9</version>
</dependency>

Maven Central