There are indeed a lot of string similarity measures out there:
- Levenshtein edit distance;
- Damerau-Levenshtein distance;
- Jaro-Winkler similarity;
- Longest Common Subsequence edit distance;
- Q-Gram (Ukkonen);
- n-Gram distance (Kondrak);
- Jaccard index;
- Sorensen-Dice coefficient;
- Cosine similarity;
- ...
You can find explanation and java implementation of these here:
https://github.com/tdebatty/java-string-similarity