Generate random numbers using Javafaker API – Java

We may require to generate random numbers in programming languages for multiple purposes like test data creation or numeric IDs for employees etc. We have multiple libraries available to generate random numbers in Java but I personally feel Javafaker APIs are easier to use compared to others.

We will learn to generate random whole numbers, decimal numbers, and also within a range in this post.

I have covered an introductory post on Javafaker API here.

I have used below Javafaker API dependency:-

  com.github.javafaker javafaker 1.0.2

Faker class in Javafaker library provides utility methods for generating fake strings, such as names, phone numbers, addresses. generate random strings with given patterns.

package FakerClassExamples;

import com.github.javafaker.Faker;

public class RandomNumberExample {
        
        public static void main(String[] args) {
                
                Faker faker = new Faker();
                // Generate random digit between 0 - 9 both inclusive
                System.out.println(faker.number().digit());
                System.out.println(faker.number().randomDigit());
                
                // Generate random digit between 1 - 9 both inclusive
                System.out.println(faker.number().randomDigitNotZero());
                
                // Generate digit of specific length
                System.out.println(faker.number().digits(3));
                System.out.println(faker.number().digits(5));
        }

}

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Generating a random number within a range is required at many times and I think Javafaker provides the easiest way to do so.

package FakerClassExamples;

import com.github.javafaker.Faker;

public class RandomNumberWithinRange {
        
        public static void main(String[] args) {
                
                Faker faker = new Faker();
                // Generate a number between 1(inclusive) to 999 (exclusive)
                System.out.println(faker.number().numberBetween(1, 999));
                
                // Generate a decimal random number within range
                System.out.println(faker.number().randomDouble(4, 10, 100));
        }

}

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There are many useful methods provided by the Javafaker library which you can explore and learn about.

You can clone above Git Repo from here.

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#HappyLearning