What is the StringUtils.replace() method in Java?

Overview

In Java, replace() is a static method of the StringUtils class which is used to replace the search string with a replacement string. The 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-sensitive in nature.

Note: Refer What is StringUtils.replaceIgnoreCase in Java? for case-insensitive matching and replacement.

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 replace(final String text, final String searchString, final String replacement, final int max)

Parameters

  • final String text: 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.

Overloaded methods:

  • public static String replace(final String text, final String searchString, final String replacement)

Code

<?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>

Explanation

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

Main.java

  • Line 1: We import the StringUtils.
  • Line 6: We define a string called text.
  • Line 7: We define the search string called searchString.
  • Line 8 - We define the replacement string called replacementString.
  • Line 9: We define the maximum number of replacements called maxReplacements.
  • Lines 10-12 - We invoke the replace() method by passing text, searchString, replacementString, and maxReplacements as parameters. The output is printed on to console.

There are two observations to be made in the output:

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

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