Java tutorial
package resource; /* * Licensed to the Apache Software Foundation (ASF) under one or more * contributor license agreements. See the NOTICE file distributed with * this work for additional information regarding copyright ownership. * The ASF licenses this file to You under the Apache License, Version 2.0 * (the "License"); you may not use this file except in compliance with * the License. You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ import org.apache.lucene.analysis.Analyzer; import org.apache.lucene.analysis.standard.StandardAnalyzer; import org.apache.lucene.document.Document; import org.apache.lucene.document.Field; import org.apache.lucene.document.LongField; import org.apache.lucene.document.StringField; import org.apache.lucene.document.TextField; import org.apache.lucene.index.DirectoryReader; import org.apache.lucene.index.IndexReader; import org.apache.lucene.index.IndexWriter; import org.apache.lucene.index.IndexWriterConfig.OpenMode; import org.apache.lucene.index.IndexWriterConfig; import org.apache.lucene.index.Term; import org.apache.lucene.search.spell.Dictionary; import org.apache.lucene.search.spell.LuceneDictionary; import org.apache.lucene.search.spell.SpellChecker; import org.apache.lucene.store.Directory; import org.apache.lucene.store.FSDirectory; import org.apache.lucene.util.Version; import org.apache.tika.exception.TikaException; import org.apache.tika.metadata.Metadata; import org.apache.tika.parser.ParseContext; import org.apache.tika.parser.html.HtmlParser; import org.apache.tika.sax.BodyContentHandler; import org.jsoup.Jsoup; import org.xml.sax.SAXException; import java.io.BufferedReader; import java.io.File; import java.io.FileInputStream; import java.io.FileNotFoundException; import java.io.IOException; import java.io.InputStreamReader; /** * Index all text files under a directory. * This is a command-line application demonstrating simple Lucene indexing. Run * it with no command-line arguments for usage information. */ public class IndexFiles { static final String INDEX_PATH = "C:\\Program Files\\Apache Software Foundation\\Tomcat 7.0\\webapps\\webapp\\lucene\\index\\"; static final String DICTIONARY_PATH = "C:\\Program Files\\Apache Software Foundation\\Tomcat 7.0\\webapps\\webapp\\lucene\\spellchecker\\"; static final String DOCS_PATH = "C:\\Program Files\\Apache Software Foundation\\Tomcat 7.0\\webapps\\webapp\\docs\\"; private IndexFiles() { } /** Index all text files under a directory. * @throws TikaException * @throws SAXException */ public static boolean createIndex() { String indexPath = INDEX_PATH; String docsPath = DOCS_PATH; boolean override = false; final File docDir = new File(docsPath); if (!docDir.exists() || !docDir.canRead()) { return false; } try { Directory dir = FSDirectory.open(new File(indexPath)); // :Post-Release-Update-Version.LUCENE_XY: Analyzer analyzer = new StandardAnalyzer(Version.LUCENE_47); IndexWriterConfig iwc = new IndexWriterConfig(Version.LUCENE_47, analyzer); if (override) { // Create a new index in the directory, removing any // previously indexed documents: iwc.setOpenMode(OpenMode.CREATE); } else { // Add new documents to an existing index: iwc.setOpenMode(OpenMode.CREATE_OR_APPEND); } IndexWriter writer = new IndexWriter(dir, iwc); indexDocs(writer, docDir); // NOTE: if you want to maximize search performance, // you can optionally call forceMerge here. This can be // a terribly costly operation, so generally it's only // worth it when your index is relatively static (ie // you're done adding documents to it): // // writer.forceMerge(1); writer.close(); createDictionary(analyzer); return true; } catch (IOException e) { return false; } } /** * Indexes the given file using the given writer, or if a directory is * given, recurses over files and directories found under the given * directory. * * NOTE: This method indexes one document per input file. This is slow. For * good throughput, put multiple documents into your input file(s). An * example of this is in the benchmark module, which can create "line doc" * files, one document per line, using the <a href= * "../../../../../contrib-benchmark/org/apache/lucene/benchmark/byTask/tasks/WriteLineDocTask.html" * >WriteLineDocTask</a>. * * @param writer * Writer to the index where the given file/dir info will be * stored * @param file * The file to index, or the directory to recurse into to find * files to index * @throws IOException * If there is a low-level I/O error * @throws TikaException * @throws SAXException */ static void indexDocs(IndexWriter writer, File file) throws IOException { // do not try to index files that cannot be read if (file.canRead()) { if (file.isDirectory()) { String[] files = file.list(); // an IO error could occur if (files != null) { for (int i = 0; i < files.length; i++) { indexDocs(writer, new File(file, files[i])); } } } else { FileInputStream fis; try { fis = new FileInputStream(file); } catch (FileNotFoundException fnfe) { // at least on windows, some temporary files raise this // exception with an "access denied" message // checking if the file can be read doesn't help return; } try { // make a new, empty document Document doc = new Document(); // Add the path of the file as a field named "path". Use a // field that is indexed (i.e. searchable), but don't // tokenize // the field into separate words and don't index term // frequency // or positional information: Field pathField = new StringField("path", file.getPath(), Field.Store.YES); doc.add(pathField); Field relativePathField = new StringField("shortPath", getRelativePath(file.getPath()), Field.Store.YES); doc.add(relativePathField); // Add the last modified date of the file a field named // "modified". // Use a LongField that is indexed (i.e. efficiently // filterable with // NumericRangeFilter). This indexes to milli-second // resolution, which // is often too fine. You could instead create a number // based on // year/month/day/hour/minutes/seconds, down the resolution // you require. // For example the long value 2011021714 would mean // February 17, 2011, 2-3 PM. doc.add(new LongField("modified", file.lastModified(), Field.Store.NO)); // Add the contents of the file to a field named "contents". // Specify a Reader, // so that the text of the file is tokenized and indexed, // but not stored. // Note that FileReader expects the file to be in UTF-8 // encoding. // If that's not the case searching for special characters // will fail. if (file.getName().endsWith(".txt")) doc.add(new TextField("contents", new BufferedReader(new InputStreamReader(fis, "UTF-8")))); if (file.getName().endsWith(".html")) { doc.add(new TextField("contents", html2String(fis), Field.Store.YES)); doc.add(new StringField("title", getHTMLTitle(file), Field.Store.YES)); } if (writer.getConfig().getOpenMode() == OpenMode.CREATE) { // New index, so we just add the document (no old // document can be there): System.out.println("adding " + file); writer.addDocument(doc); } else { // Existing index (an old copy of this document may have // been indexed) so // we use updateDocument instead to replace the old one // matching the exact // path, if present: System.out.println("updating " + file); try { writer.updateDocument(new Term("path", file.getPath()), doc); } catch (Exception e) { // TODO e.printStackTrace(); } } } finally { fis.close(); } } } } private static String getHTMLTitle(File file) throws IOException { return Jsoup.parse(file, "UTF-8", "").title(); } private static String getRelativePath(String path) { int startCut = path.indexOf("docs"); return path.substring(startCut); } private static String html2String(FileInputStream fis) { BodyContentHandler handler = new BodyContentHandler(); Metadata metadata = new Metadata(); try { new HtmlParser().parse(fis, handler, metadata, new ParseContext()); } catch (IOException | SAXException | TikaException e) { e.printStackTrace(); } return handler.toString(); } private static void createDictionary(Analyzer analyzer) throws IOException { Directory dictionaryDir = FSDirectory.open(new File(DICTIONARY_PATH)); Directory indexDir = FSDirectory.open(new File(INDEX_PATH)); IndexReader reader = DirectoryReader.open(indexDir); Dictionary dictionary = new LuceneDictionary(reader, "contents"); IndexWriterConfig iwc = new IndexWriterConfig(Version.LUCENE_47, analyzer); SpellChecker spellChecker = new SpellChecker(dictionaryDir); spellChecker.indexDictionary(dictionary, iwc, false); spellChecker.close(); } }