In this post we will see different methods of generate random number and String in Java.
Generate Random Number in java
Logic 1- Using Random class
package demopkg; import java.util.Random; public class GenRandomNumber { public static void main(String[] args) { //Logic 1 - Using Random class Random rand = new Random(); int random_num=rand.nextInt(100); System.out.println(random_num); } }
Code Explanation:
Random is a class. nextInt () is a method by using we can generate random number.
Note: There are so many methods in Random class like – nextDouble(), nextFloat(), nextBoolean(), nextLong() etc. to generate the random number.
Logic 2 – Using Math class
package demopkg; import java.util.Random; public class genRandomNumber2 { public static void main(String[] args) { //Logic 2 - Using Math class System.out.println(Math.random()); } }
Code Explanation:
Math is a class. random() is a static method by using we can generate double format random number.
Logic 3 – Generate random alphanumeric string in java
package demopkg; import org.apache.commons.lang3.RandomStringUtils; public class GenRandomAlphbeticString { public static void main(String[] args) { // Logic 3- Apache commons API // Generate random numeric String randNum = RandomStringUtils.randomNumeric(4); System.out.println(randNum); // Generate random String String randStr = RandomStringUtils.randomAlphabetic(5); System.out.println(randStr); } }
Code Explanation:
First we need to download Apache commons lang API jars from here – Then import into your project.
There is a RandomStringUtils class which have different methods like randomNumeric(), randomeAlphabetic() etc.
How to Generate Random Characters in Java
Read this link – Generate Random Characters