Lucene : Search with partial words

Question

I am working on integrating Lucene in our application. Lucene is currently working, for example when I am searching "Upload" and there is some text called "Upload" in a document, then it works, but when I search "Uplo", then it doesn't work. Any ideas?

Code :

  Directory directory = FSDirectory.open(path);
                IndexReader indexReader = DirectoryReader.open(directory);
                IndexSearcher indexSearcher = new IndexSearcher(indexReader);

                QueryParser queryParser = new QueryParser("contents", new SimpleAnalyzer());
                Query query = queryParser.parse(text);
                TopDocs topDocs = indexSearcher.search(query, 50);
                for (ScoreDoc scoreDoc : topDocs.scoreDocs) {
                    org.apache.lucene.document.Document document = indexSearcher.doc(scoreDoc.doc);
                    objectIds.add(Integer.valueOf(document.get("id")));
                    System.out.println("");
                    System.out.println("id " + document.get("id"));
                    System.out.println("content " + document.get("contents"));
                }
                return objectIds;

Thank you.

Answer 1

'Upload' might be ONE Token in your Lucene index where a Token would be the smallest entity non splittable further. If you want to match partial words like 'Uplo' then it is better to go for Lucene NGram Indexing . Note that if you go for NGram indexing you will have higher space requirements for your inverted index.

Answer 2

You can use wildcard searches.

"?" symbol for single character wildcard search and "*" symbol for Multiple character wildcard searches (0 or more characters).

example - "Uplo*"

Answer 3

Change

Query query = queryParser.parse(text);

To

 Query query = queryParser.parse("*"+text+"*");

Lucene supports single and multiple character wildcard searches within single terms (not within phrase queries).

To perform a single character wildcard search use the "?" symbol.

To perform a multiple character wildcard search use the "*" symbol.

The single character wildcard search looks for terms that match that with the single character replaced. For example, to search for "text" or "test" you can use the search:

te?t

Multiple character wildcard searches looks for 0 or more characters. For example, to search for test, tests or tester, you can use the search:

test*

You can also use the wildcard searches in the middle of a term.

te*t

Note: You cannot use a * or ? symbol as the first character of a search.