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How to compare Dates in Java programming?

Updated on January 9, 2014

Date comparison is one of the popular tasks for Java application developer or Java programmer. You may need to compare dates for online order processing, form validation checking, data validation checking based on dates, protect several user activities based on date constraints, protects user to edit / update back dated data, to create order more than 2 weeks advanced date etc. These are the some common situation, you may need to compare dates. Comparing dates is not a very easy task and most of the time people need much time to do it exactly and very easily. But this can be easily done by using some methods of Dates or Calendar class. This page provides you three popular options which can be used to compare between dates. You may choose any of the options. Sometime option one is the best and sometimes option three is the best. Whatever the option is, any of them can be use for the same purpose. All the options summarize are:

  • Option One: Using compareTo method of Date class
  • Option Two: Using before, after and equals method of Date class
  • Option Three: Using before, after and equals methods of Calender class

Using compareTo method of Date class

  • compareTo method compares two Dates for ordering.
  • if both Dates are equal, compareTo method returns 0
  • if Date is after the Date in argument, compareTo method returns a value which is greater than 0
  • if Date is before the Date in argument, compareTo method returns a value which is less than 0

Step 1:

Create two "String" type fields and initialize those values by the two date string. For example, we have two Date String ("2014/01/01" and "2012/12/29") and using Java we define like the following:

String dateString1 = "2014/01/01";
String dateString2 = "2012/12/29";

Step 2:

Use "SimpleDateFormat" class and define the format by which the date String is defined. The Java code for doing this is the following:

SimpleDateFormat simpleDateFormat = new SimpleDateFormat("yyyy/MM/dd");

Step 3:

Define two Date object and convert both of the Date String into default Date format. The codes for doing this is the following:

Date date1 = simpleDateFormat.parse(dateString1);
Date date2 = simpleDateFormat.parse(dateString2);

Step 4:

Use "compareTo" method with if-else block to check and implement your logic. The Java codes for this are the following:

			if (date1.after(date2)) {
			 System.out.println("Date1 is most recent");
			 }
			
			 if (date1.before(date2)) {
			 System.out.println("Date2 is most recent");
			 }
			
			 if (date1.equals(date2)) {
			 System.out.println("Both dates are equal");
			 }

Step 5:

Run the program and examine whether the code is working properly or not.

Example: Full Java Code

package com.hubpages.plusminus;

import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.Date;

public class DateComparison {

	public static void main(String[] args) {

		String dateString1 = "2014/01/01";
		String dateString2 = "2012/12/29";

		SimpleDateFormat simpleDateFormat = new SimpleDateFormat("yyyy/MM/dd");

		try {
			Date date1 = simpleDateFormat.parse(dateString1);
			Date date2 = simpleDateFormat.parse(dateString2);
			System.out.println("Value of Date1 is:" + date1);
			System.out.println("Value of Date2 is:" + date2);

			if (date1.compareTo(date2) > 0) {
				System.out.println("Date1 is most recent");
			}

			else if (date1.compareTo(date2) < 0) {
				System.out.println("Date2 is most recent");
			}

			else {
				System.out.println("Both dates are equal");
			}

		} catch (ParseException e) {
			e.printStackTrace();
		}

	}

}

Sample output

Using before, after and equals method of Date class

  • boolean after(Date when): tests if this date is after the specified date
  • boolean before(Date when): tests if this date is before the specified date
  • boolean equals(Object obj): compares two dates for equality.

Step 1:

Create two "String" type fields and initialize those values by the two date string. For example, we have two Date String ("2014/01/01" and "2012/12/29") and using Java we define like the following:

		String dateString1 = "2014/01/01";
		String dateString2 = "2012/12/29";

Step 2:

Use "SimpleDateFormat" class and define the format by which the date String is defined. The Java code for doing this is the following:

		SimpleDateFormat simpleDateFormat = new SimpleDateFormat("yyyy/MM/dd");

Step 3:

Define two Date object and convert both of the Date String into default Date format. The codes for doing this is the following:

			Date date1 = simpleDateFormat.parse(dateString1);
			Date date2 = simpleDateFormat.parse(dateString2);

Step 4:

Now use the methods after, before and equals and implement your logic using if block. Necessary codes for these are the following:

			if (date1.after(date2)) {
				System.out.println("Date1 is most recent");
			}

			if (date1.before(date2)) {
				System.out.println("Date2 is most recent");
			}

			if (date1.equals(date2)) {
				System.out.println("Both dates are equal");
			}

Example: Full Java Code

package com.hubpages.plusminus;

import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.Date;

public class DateComparison {

	public static void main(String[] args) {

		String dateString1 = "2014/01/01";
		String dateString2 = "2012/12/29";

		SimpleDateFormat simpleDateFormat = new SimpleDateFormat("yyyy/MM/dd");

		try {
			Date date1 = simpleDateFormat.parse(dateString1);
			Date date2 = simpleDateFormat.parse(dateString2);
			System.out.println("Value of Date1 is:" + date1);
			System.out.println("Value of Date2 is:" + date2);

			if (date1.after(date2)) {
				System.out.println("Date1 is most recent");
			}

			if (date1.before(date2)) {
				System.out.println("Date2 is most recent");
			}

			if (date1.equals(date2)) {
				System.out.println("Both dates are equal");
			}

		} catch (ParseException e) {
			e.printStackTrace();
		}

	}

}

Sample output

Using before, after and equals methods of Calender class

  • boolean after(Object when): Returns whether this Calendar represents a time after the time represented by the specified Object.
  • boolean before(Object when): Returns whether this Calendar represents a time before the time represented by the specified Object.
  • boolean equals(Object obj): Compares this Calendar to the specified Object.

Step 1:

Create two "String" type fields and initialize those values by the two date string. For example, we have two Date String ("2014/01/01" and "2012/12/29") and using Java we define like the following:

		String dateString1 = "2014/01/01";
		String dateString2 = "2012/12/29";

Step 2:

Use "SimpleDateFormat" class and define the format by which the date String is defined. The Java code for doing this is the following:

SimpleDateFormat simpleDateFormat = new SimpleDateFormat("yyyy/MM/dd");

Step 3:

Define two Date object and convert both of the Date String into default Date format. The codes for doing this is the following:

			Date date1 = simpleDateFormat.parse(dateString1);
			Date date2 = simpleDateFormat.parse(dateString2);	

Step 4:

Use "Calendar" class to create two calendar object and set this Calendar's time with the given Date. Codes for this are like the following:

			Calendar calendar1 = Calendar.getInstance();
			Calendar calendar2 = Calendar.getInstance();

Step 5:

Now use the methods after, before and equals and implement your logic using if block. Necessary codes for these are the following:

			if (calendar1.after(calendar2)) {
				System.out.println("Date1 is most recent");
			}

			if (calendar1.before(calendar2)) {
				System.out.println("Date2 is most recent");
			}

			if (calendar1.equals(calendar2)) {
				System.out.println("Both dates are equal");
			}

Step 6:

Run the program and examine whether the code is working properly or not.

Example: Full Java Code

package com.hubpages.plusminus;

import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.Calendar;
import java.util.Date;

public class DateComparison {

	public static void main(String[] args) {

		String dateString1 = "2014/01/01";
		String dateString2 = "2012/12/29";

		SimpleDateFormat simpleDateFormat = new SimpleDateFormat("yyyy/MM/dd");

		try {
			Date date1 = simpleDateFormat.parse(dateString1);
			Date date2 = simpleDateFormat.parse(dateString2);
			System.out.println("Value of Date1 is:" + date1);
			System.out.println("Value of Date2 is:" + date2);

			Calendar calendar1 = Calendar.getInstance();
			Calendar calendar2 = Calendar.getInstance();

			calendar1.setTime(date1);
			calendar2.setTime(date2);

			if (calendar1.after(calendar2)) {
				System.out.println("Date1 is most recent");
			}

			if (calendar1.before(calendar2)) {
				System.out.println("Date2 is most recent");
			}

			if (calendar1.equals(calendar2)) {
				System.out.println("Both dates are equal");
			}

		} catch (ParseException e) {
			e.printStackTrace();
		}

	}

}

Sample output

Hopefully, comparisons between two days is not very complex but it has some steps. Following the above codes and explanation, I think you can easily compare between two dates. You can use any of the options. There is no hard and fast rules that you must have to use any of the option.

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