Compare time in Java

Most of the time we need to compare two date and date-time objects. Date comparison is required when we want to get the data of some specific date and time from the database or to filter the returned data based on date and time.

In order to compare time, we use the compareTo() method of the LocalTime class. The compareTo() method of the class compares two LocalTime objects. The first LocalTime object is one which we want to compare, and the second object is which we pass to the compareTo() method as a parameter and from which we want to compare this LocalTime object.

Syntax:

The compareTo() method of the LocalTime class is as follows:

Parameters:

It accepts only a single parameter, i.e., the LocalTime object, which is going to be compared, and it should not be null.

Returns:

The compareTo() method returns three values based on the comparison of the objects:

It returns a positive value when this LocalTime object is greater than the specified LocalTime object.
It returns a negative value when this LocalTime object is smaller than the specified LocalTime object.
It returns zero when this LocalTime object is equal to the specified LocalTime object.

Let's take some examples to understand how the compareTo() method is used for the comparison of two LocalTime objects.

CompareToExample1.java

// import required classes and packages
import java.time.*;
import java.util.Scanner;
// create CompareToExample1 class to understand the working of CompareTo() method
public class CompareToExample1 {
	// main() method start
	public static void main(String[] args)
	{
		// declare variable for initialize LocalTime
		int hour1, hour2, min1, min2, sec1, sec2;
		LocalTime time1, time2;
		// create Scanner class object to take input from the user for initializing LocalTime
		Scanner sc = new Scanner(System.in);
		// get input from used for initializing time1
		System.out.println("Enter time for initializing the first LocaleTime object:");
		System.out.println("Enter hours:");
		hour1 = sc.nextInt();
		System.out.println("Enter minutes:");
		min1 = sc.nextInt();
		System.out.println("Enter seconds:");
		sec1 = sc.nextInt();
		// initialize LocalTime object for time1
		time1 = LocalTime.of(hour1, min1, sec1);
		// get input from used for initializing time2
		System.out.println("Enter time for initializing the second LocaleTime object:");
		System.out.println("Enter hours:");
		hour2 = sc.nextInt();
		System.out.println("Enter minutes:");
		min2 = sc.nextInt();
		System.out.println("Enter seconds:");
		sec2 = sc.nextInt();
		// close scanner class object
		sc.close();
		// initialize LocalTime object for time2
		time2 = LocalTime.of(hour2, min2, sec2);
		// use compareTo() method to compare time1 and time2 objects
		int returnVal = time1.compareTo(time2);
		// print value return by 
		System.out.println("Value returned by comparTo() method:" + returnVal);
		// check whether the time1 object is greater, smaller or equal to time2
		if (returnVal > 0) {
			System.out.println("time1 is greater than time2.");
		}else if (returnVal == 0) {
			System.out.println("time1 is equal to time2.");
		}else {
			System.out.println("time1 is smaller than time2.");
		}
	}
}

Output:

Let's take one more example to understand the concept of the compareTo() method. In this example, we will compare two date-time objects by using the compareTo() method.

CompareToExample2.java

//import required classes and packages
package javaTpoint.JavaExample;

import java.time.*;
import java.util.Scanner;

//create CompareToExample1 class to understand the working of CompareTo() method
public class CompareToExample2 {
	
	// main() method start
	public static void main(String[] args)
	{
		// declare variable for initialize LocaleDateTime
		int hour1, hour2, min1, min2, sec1, sec2, yr1, yr2, month1, month2, day1, day2;
		LocalDateTime date1, date2;
		
		// create Scanner class object to take input from the user for initializing LocaleDateTime
		Scanner sc = new Scanner(System.in);
		
		// get input from used for initializing date1
		System.out.println("Enter Datetime for initializing the first LocaleDateTime object:");
		System.out.println("Enter year:");
		yr1 = sc.nextInt();
		System.out.println("Enter month:");
		month1 = sc.nextInt();
		System.out.println("Enter day:");
		day1 = sc.nextInt();
		System.out.println("Enter hours:");
		hour1 = sc.nextInt();
		System.out.println("Enter minutes:");
		min1 = sc.nextInt();
		System.out.println("Enter seconds:");
		sec1 = sc.nextInt();
		
		// initialize LocaleDateTime object for date1
		date1 = LocalDateTime.of(yr1, month1, day1, hour1, min1, sec1);
		System.out.println("Date1: " + date1);
		
		// get input from used for initializing time2
		System.out.println("Enter Datetime for initializing the second LocaleDateTime object:");
		System.out.println("Enter year:");
		yr2 = sc.nextInt();
		System.out.println("Enter month:");
		month2 = sc.nextInt();
		System.out.println("Enter day:");
		day2 = sc.nextInt();
		System.out.println("Enter hours:");
		hour2 = sc.nextInt();
		System.out.println("Enter minutes:");
		min2 = sc.nextInt();
		System.out.println("Enter seconds:");
		sec2 = sc.nextInt();
		
		// close scanner class object
		sc.close();
		
		// initialize LocalTime object for date2
		date2 = LocalDateTime.of(yr2, month2, day2, hour2, min2, sec2);
		System.out.println("Date2: " + date2);
		
		// use compareTo() method to compare date1 and date2 objects
		int returnVal = date1.compareTo(date2);

		// print value return by 
		System.out.println("Value returned by comparTo() method:" + returnVal);
		
		// check whether the date1 object is greater, smaller or equal to date2
		if (returnVal > 0) {
			System.out.println("date1 is greater than date2.");
		}else if (returnVal == 0) {
			System.out.println("date1 is equal to date2.");
		}else {
			System.out.println("date1 is smaller than date2.");
		}
	}
}

Output: