Generating Random Strings with Apache Commons Lang

Generating Random Strings with Apache Commons Lang | Generated by AI

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RandomStringUtils is a highly useful class from the Apache Commons Lang library that provides various static methods for generating random strings. This includes generating strings with specific lengths, containing only letters, only numbers, alphanumeric characters, or even from a custom set of characters.

Here’s how to use it and the necessary Maven dependency:

How to use `org.apache.commons.lang3.RandomStringUtils;`

First, you need to import the class in your Java file:

import org.apache.commons.lang3.RandomStringUtils;

Then you can use its static methods. Here are some common examples:

Generate a random alphanumeric string of a specific length:

String randomAlphaNumeric = RandomStringUtils.randomAlphanumeric(10);
System.out.println("Random alphanumeric: " + randomAlphaNumeric); // e.g., "aB5cY2x9Pq"

Generate a random alphabetic string of a specific length:

String randomAlphabetic = RandomStringUtils.randomAlphabetic(8);
System.out.println("Random alphabetic: " + randomAlphabetic); // e.g., "GhJkLmNo"

Generate a random numeric string of a specific length:

String randomNumeric = RandomStringUtils.randomNumeric(6);
System.out.println("Random numeric: " + randomNumeric); // e.g., "123456"

Generate a random string with a mix of letters and numbers, specifying flags:

String randomLettersAndNumbers = RandomStringUtils.random(12, true, true);
System.out.println("Random letters and numbers: " + randomLettersAndNumbers); // e.g., "abC123DeF456"

Generate a random string from a custom set of characters:

String chars = "abcdefg";
String randomFromCustomSet = RandomStringUtils.random(5, chars);
System.out.println("Random from custom set: " + randomFromCustomSet); // e.g., "gcfae"

What library to use in `pom.xml`

To use RandomStringUtils in a Maven project, you need to add the commons-lang3 dependency to your pom.xml file.

Here’s the dependency snippet:

<dependency>
    <groupId>org.apache.commons</groupId>
    <artifactId>commons-lang3</artifactId>
    <version>3.14.0</version> </dependency>

Important Notes:

Version: Always check Maven Central for the latest stable version of commons-lang3. As of my last update, 3.14.0 or higher is a good choice, but it’s always best to use the absolute latest stable version available.
Scope: The default scope for dependencies is compile, which is usually what you want for utility libraries like this. It means the JAR will be available during compilation, testing, and runtime. If you were only using it for testing, you might use <scope>test</scope>.
Deprecation: Note that some older methods like RandomStringUtils.randomAlphabetic(int count) are deprecated in newer versions of Apache Commons Lang 3. Instead, it’s recommended to use the secure(), secureStrong(), or insecure() methods, which provide more control over the randomness source. For example, RandomStringUtils.secure().nextAlphanumeric(10). However, the older methods still work for many use cases.

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