If you want to use Slugify in your JSPs you need the JSTL Integration and the library itself. Here's the dependency information for Maven:
<dependency>
<groupId>com.github.slugify</groupId>
<artifactId>slugify-integration-jstl</artifactId>
<version>2.4</version>
</dependency>
Now you're able to use it:
<%@ taglib prefix="slg" uri="http://github.com/slugify" %>
<!-- Result: hello-world -->
${slg:slugify('Hello, world!')}
You can configure Slugify this way (JSTL):
<%@ taglib prefix="slg" uri="http://github.com/slugify" %>
<slg:init lowerCase="false" underscoreSeparator="true" />
<!-- Result: Hello_world -->
${slg:slugify('Hello, world!')}
Or this way (Java):
InitSlugifyTag.getSlugify().withLowerCase(false).withUnderscoreSeparator(true);