Prait my Blog

Useful links to start with Lucene:
http://www.lucenetutorial.com/lucene-in-5-minutes.html
http://stackoverflow.com/questions/468405/how-to-incorporate-multiple-fields-in-queryparser
Here an example how to index and search text:

package ch.prait.lucene;

import java.io.File;
import java.util.ArrayList;
import java.util.List;

import org.apache.lucene.analysis.KeywordAnalyzer;
import org.apache.lucene.analysis.standard.StandardAnalyzer;
import org.apache.lucene.document.Document;
import org.apache.lucene.document.Field;
import org.apache.lucene.index.IndexReader;
import org.apache.lucene.index.IndexWriter;
import org.apache.lucene.index.IndexWriterConfig;
import org.apache.lucene.queryParser.QueryParser;
import org.apache.lucene.search.IndexSearcher;
import org.apache.lucene.search.Query;
import org.apache.lucene.search.ScoreDoc;
import org.apache.lucene.search.TopScoreDocCollector;
import org.apache.lucene.store.Directory;
import org.apache.lucene.store.SimpleFSDirectory;
import org.apache.lucene.util.Version;

public class PrettyLucene {

	public void index(Directory index, List<String> stringsToIndex, String teller) throws Exception {
		// create an analyzer
		StandardAnalyzer analyzer = new StandardAnalyzer(Version.LUCENE_36);

		// Create the index writer
		IndexWriterConfig config = new IndexWriterConfig(Version.LUCENE_36, analyzer);
		IndexWriter w = new IndexWriter(index, config);

		int idCounter = 0;
		for (String stringToIndex : stringsToIndex) {

			// create a document and add three fields to it whereas 2 are analyzed and one is just
			// information stored
			Document myDocument = new Document();
			myDocument.add(new Field("myString", stringToIndex, Field.Store.YES, Field.Index.ANALYZED));
			myDocument.add(new Field("id", String.valueOf(idCounter), Field.Store.YES, Field.Index.ANALYZED));
			myDocument.add(new Field("teller", teller, Field.Store.YES, Field.Index.NO));
			w.addDocument(myDocument);
		}
		// close all handles
		w.close();
	}

	public void searchIndex(Directory index, String searchTerm) throws Exception {
		// create an analyzer
		KeywordAnalyzer analyzer = new KeywordAnalyzer();

		// create a topScore Collection and display the results
		int hitsPerPage = 10;
		IndexReader reader = IndexReader.open(index);

		IndexSearcher searcher = new IndexSearcher(reader);
		TopScoreDocCollector collector = TopScoreDocCollector.create(hitsPerPage, true);
		QueryParser parser = new QueryParser(Version.LUCENE_36, "myString", analyzer);
		Query q = parser.parse(searchTerm);
		searcher.search(q, collector);
		ScoreDoc[] hits = collector.topDocs().scoreDocs;

		System.out.println("Found " + hits.length + " hits.");
		for (int i = 0; i < hits.length; ++i) {
			int docId = hits[i].doc;
			Document d = searcher.doc(docId);
			System.out.println((i + 1) + ". " + "Line " + d.get("id") + " told by " + d.get("teller") + ": "
					+ d.get("myString"));
		}
		reader.close();
	}

	public static void main(String[] args) {

		PrettyLucene prettyLucene = new PrettyLucene();
		try {
			// makes a directory luceneIndex where you start the program. In this folder
			// lucene will put the index files
			Directory index = new SimpleFSDirectory(new File("luceneIndex"));

			List<String> marcellus = new ArrayList<String>();
			marcellus.add("Horatio says 'tis but our fantasy,");
			marcellus.add("And will not let belief take hold of him");
			marcellus.add("Touching this dreaded sight, twice seen of us:");
			marcellus.add("Therefore I have entreated him along");
			marcellus.add("With us to watch the minutes of this night;");
			marcellus.add("That if again this apparition come,");
			marcellus.add("He may approve our eyes and speak to it.");
			prettyLucene.index(index, marcellus, "Marcellus");

			List<String> horatio = new ArrayList<String>();
			horatio.add("What art thou that usurp'st this time of night,");
			horatio.add("Together with that fair and warlike form");
			horatio.add("In which the majesty of buried Denmark");
			horatio.add("Did sometimes march? by heaven I charge thee, speak!");
			prettyLucene.index(index, horatio, "Horatio");

			prettyLucene.searchIndex(index, "speak*");

			index.close();

		} catch (Exception e) {
			e.printStackTrace();
		}

	}
}