What is the StringUtils.replaceIgnoreCase method in Java?

Overview

In Java, the replaceIgnoreCase() is a static method of the StringUtils class that is used to replace the search string with a replacement string. This method optionally accepts the first maximum number of matches of the search string to be replaced in the given text. The string matching here is case-insensitive in nature.

Note: Refer What is StringUtils.replace() in Java? for case-sensitive matching and replacement.

Import StringUtils

The definition of StringUtils can be found in the Apache Commons Lang package, which we can add to the Maven project by adding the following dependency to the pom.xml file.

<dependency>
            <groupId>org.apache.commons</groupId>
            <artifactId>commons-lang3</artifactId>
            <version>3.12.0</version>
</dependency>

Note: For other versions of the commons.lang package, refer to the Maven Repository.

We can import the StringUtils class as follows:

import org.apache.commons.lang3.StringUtils;

Syntax

public static String replaceIgnoreCase(final String text, final String searchString, final String replacement, final int max)

Parameters

• final String text: The text to search and replace in.
• final String searchString: The string to search for.
• final String replacement: The replacement string.
• final int max: The first maximum number of values to replace.

Return value

This method returns the text with the search string replaced with the replacement string.

Example

Explanation

The maven dependency for StringUtils is included in the pom.xml file:

Main.java

• Line 1: We import the StringUtils class.
• Line 6: We define a String, text.
• Line 7: We define the search string, searchString.
• Line 8: We define the replacement string, replacementString.
• Line 9: We define the maximum number of replacements, maxReplacements.
• Lines 10–12: We invoke the replaceIgnoreCase() method passing text, searchString, replacementString and maxReplacements as parameters. We print the output to the console.

Two observations to be made in the output:

1. The comparison and replacement are case-insensitive in nature.
2. Only the first maxReplacements occurrences of the searchString are replaced.