Introduction

In Java, converting a string to lower case can be done using different methods depending on your requirements. In this tutorial, we will explore three common approaches to achieve this.

1. Using the toLowerCase() Method

The toLowerCase() method is a built-in string method in Java that converts all the characters in a string to lower case. Here’s an example:

String str = ""Hello World"";
String lowerCaseStr = str.toLowerCase();

System.out.println(lowerCaseStr); // Output: hello world

In the code above, we create a string str with the value ""Hello World"". We then use the toLowerCase() method to convert the string to lower case and store the result in lowerCaseStr.

2. Using the toLowerCase(Locale) Method

The toLowerCase(Locale) method is similar to toLowerCase(), but it allows you to specify a specific Locale for the conversion. This is useful when dealing with languages that have specific casing rules. Here’s an example:

String str = ""HÉLLÓ WÖRLD"";
String lowerCaseStr = str.toLowerCase(Locale.ROOT);

System.out.println(lowerCaseStr); // Output: hélló wörld

In the code above, we convert a string str with the value ""HÉLLÓ WÖRLD"" to lower case using the toLowerCase(Locale.ROOT) method. The Locale.ROOT is a constant representing the root locale, which is a neutral, platform-independent locale.

3. Using the Apache Commons Text Library

If you are using the Apache Commons Text library, you can use the StringUtils class to convert a string to lower case. First, you need to add the library as a dependency in your project. Then, you can use the StringUtils.lowerCase() method as shown in the example below:

import org.apache.commons.text.*;

String str = ""Hello World"";
String lowerCaseStr = StringUtils.lowerCase(str);

System.out.println(lowerCaseStr); // Output: hello world

In the code above, we import the StringUtils class from the Apache Commons Text library and use its lowerCase() method to convert the string to lower case.

These are three common approaches to convert a string to lower case in Java. Choose the method that best suits your needs based on the requirements of your project. Happy coding!

I hope you found this tutorial helpful!