java 37 lines · 8 steps

Building a URL slugifier in Java

Turn arbitrary titles into clean, hyphenated URL slugs by normalizing Unicode and scrubbing with precompiled regexes.

Explained by highlit
Intermediate regex unicode-normalization string-processing utility-class
1public final class Slugifier {
2 
3 private static final Pattern NON_LATIN = Pattern.compile("[^\\w-]");
4 private static final Pattern WHITESPACE = Pattern.compile("[\\s]+");
5 private static final Pattern EDGE_DASHES = Pattern.compile("(^-+)|(-+$)");
6 private static final Pattern MULTI_DASH = Pattern.compile("-{2,}");
7 
8 private Slugifier() {
9 }
10 
11 public static String slugify(String title) {
12 if (title == null || title.isBlank()) {
13 return "";
14 }
15 
16 String normalized = Normalizer.normalize(title, Normalizer.Form.NFD)
17 .replaceAll("\\p{InCombiningDiacriticalMarks}+", "");
18 
19 String slug = WHITESPACE.matcher(normalized.trim()).replaceAll("-");
20 slug = slug.toLowerCase(Locale.ENGLISH);
21 slug = NON_LATIN.matcher(slug).replaceAll("");
22 slug = MULTI_DASH.matcher(slug).replaceAll("-");
23 slug = EDGE_DASHES.matcher(slug).replaceAll("");
24 
25 return slug;
26 }
27 
28 public static String slugify(String title, int maxLength) {
29 String slug = slugify(title);
30 if (slug.length() <= maxLength) {
31 return slug;
32 }
33 String truncated = slug.substring(0, maxLength);
34 int lastDash = truncated.lastIndexOf('-');
35 return lastDash > 0 ? truncated.substring(0, lastDash) : truncated;
36 }
37}
01 / 01
STEP 01

Walkthrough

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Three takeaways
  1. 1Precompiling patterns as constants avoids recompiling regexes on every call.
  2. 2Unicode NFD decomposition lets you strip diacritics by removing combining marks.
  3. 3Order matters when chaining string transforms — each step assumes the previous one's output shape.

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