What is StringUtils.replaceChars in Java?

Overview

The replaceChars() is a static method of the StringUtils class that is used to replace all the occurrences of the search character with the replacement character.

A null search string returns null as output and an empty search string returns an empty string as output.

How to 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 replaceChars(final String str, final char searchChar, final char replaceChar)

Parameters

  • final String text: The text to search and replace.
  • final char searchChar: The character to search for.
  • final char replaceChar: The replacement character.

Return value

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

Code example

Let’s look at the code below:

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>org.example</groupId>
    <artifactId>test</artifactId>
    <version>1.0-SNAPSHOT</version>

    <properties>
        <maven.compiler.source>8</maven.compiler.source>
        <maven.compiler.target>8</maven.compiler.target>
    </properties>

    <dependencies>

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

    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-shade-plugin</artifactId>
                <version>2.1</version>
                <executions>
                    <execution>
                        <phase>package</phase>
                        <goals>
                            <goal>shade</goal>
                        </goals>
                        <configuration>
                            <transformers>
                                <transformer
                                        implementation="org.apache.maven.plugins.shade.resource.ManifestResourceTransformer">
                                    <mainClass>Main</mainClass>
                                </transformer>
                            </transformers>
                        </configuration>
                    </execution>
                </executions>
            </plugin>
        </plugins>
    </build>

</project>

Code explanation

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

Let’s get into a detailed explanation of the Main.java class:

  • Line 1: We import the StringUtils class.
  • Line 6: We define a String called text.
  • Line 7: We define the search character called searchChar.
  • Line 8: We define the replacement character called replacementChar.
  • Lines 8 to 10: We invoke the replaceChars() method, passing text, searchChar and replacementChar as parameters. The output is stored in paddedText. The output consists of the text where all the occurrences of searchChar are replaced by replacementChar.

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