What is the StringUtils.stripToNull method in Java?
Overview
In Java, stripToNull() is a static method of the StringUtils class that is used to strip all the leading and trailing whitespace from the given string. The method returns null if the resultant string is empty ("") after the strip.
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-langpackage, refer to the Maven Repository.
We can import the StringUtils class as follows:
import org.apache.commons.lang3.StringUtils;
Syntax
public static String stripToNull(final String str)
Parameters
This method takes the parameter, final String str, which is the string to be stripped.
Return value
This method returns a new string with all the leading and trailing whitespace removed from the input string.
<?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
There are four examples used in the code, explained one by one in this section.
Example 1
string - " 543234asfg "
The method returns 543234asfg with all the leading and trailing whitespaces removed from the input string.
Example 2
string - ""
The method returns null, as the input string is empty.
Example 3
string - null
The method returns null because the string points to a null reference.
Example 4
string - " "
The method returns null, as the resultant string after the strip is an empty string.
