Java tutorial
package model; /* * 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 java.io.BufferedReader; import java.io.FileReader; import java.io.IOException; import java.io.InputStream; import java.nio.file.FileVisitResult; import java.nio.file.Files; import java.nio.file.Path; import java.nio.file.Paths; import java.nio.file.SimpleFileVisitor; import java.nio.file.attribute.BasicFileAttributes; import java.util.Arrays; import java.util.Date; import java.util.HashMap; import java.util.List; import java.util.regex.Matcher; import java.util.regex.Pattern; import org.jsoup.Jsoup; import org.apache.lucene.analysis.Analyzer; import org.apache.lucene.analysis.core.StopFilter; import org.apache.lucene.analysis.en.EnglishAnalyzer; import org.apache.lucene.analysis.standard.StandardAnalyzer; import org.apache.lucene.analysis.util.CharArraySet; 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.IndexWriter; import org.apache.lucene.index.IndexWriterConfig; import org.apache.lucene.index.IndexWriterConfig.OpenMode; import org.apache.lucene.index.Term; import org.apache.lucene.store.Directory; import org.apache.lucene.store.FSDirectory; import org.apache.lucene.util.Version; //import org.apache.lucene.StopAnalyzer.ENGLISH_STOP_WORDS_SET*; /** Index all text files under a directory. * <p> * This is a command-line application demonstrating simple Lucene indexing. * Run it with no command-line arguments for usage information. */ public class IndexFiles { public IndexFiles() { /** Index all text files under a directory. */ String indexPath = "index"; String docPath = "data"; boolean create = true; if (docPath == null) { System.exit(1); } final Path docDir = Paths.get(docPath); if (!Files.isReadable(docDir)) { System.out.println("Document directory '" + docDir.toAbsolutePath() + "' does not exist or is not readable, please check the path"); System.exit(1); } Date start = new Date(); try { System.out.println("Indexing to directory '" + indexPath + "'..."); Directory dir = FSDirectory.open(Paths.get(indexPath)); final List<String> stopWords = Arrays.asList("a", "an", "are", "as", "at", "be", "but", "by", "in", "into", "is", "it", "no", "on", "such", "that", "the", "their", "then", "there", "these", "they", "to", "was", "will", "with"); //final List<String> stopWords = Arrays.asList("for", "if"); final CharArraySet stopSet = new CharArraySet(stopWords, false); Analyzer analyzer = new StandardAnalyzer(stopSet); IndexWriterConfig iwc = new IndexWriterConfig(analyzer); if (create) { // 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); } // Optional: for better indexing performance, if you // are indexing many documents, increase the RAM // buffer. But if you do this, increase the max heap // size to the JVM (eg add -Xmx512m or -Xmx1g): // iwc.setRAMBufferSizeMB(256.0); 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(); Date end = new Date(); System.out.println(end.getTime() - start.getTime() + " total milliseconds"); } catch (IOException e) { System.out.println(" caught a " + e.getClass() + "\n with message: " + e.getMessage()); } } /** * 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 path 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 */ static void indexDocs(final IndexWriter writer, Path path) throws IOException { if (Files.isDirectory(path)) { Files.walkFileTree(path, new SimpleFileVisitor<Path>() { @Override public FileVisitResult visitFile(Path file, BasicFileAttributes attrs) throws IOException { try { String fileName = file.getFileName().toString(); if (fileName.endsWith("gif") || fileName.endsWith("jpg")) { throw new IOException(); } else { indexDoc(writer, file, attrs.lastModifiedTime().toMillis()); } } catch (IOException ignore) { // don't index files that can't be read. } return FileVisitResult.CONTINUE; } }); } else { indexDoc(writer, path, Files.getLastModifiedTime(path).toMillis()); } } /** Indexes a single document */ static void indexDoc(IndexWriter writer, Path file, long lastModified) throws IOException { HashMap<String, String> mappingPathToTitle = new HashMap<String, String>(); try (InputStream stream = Files.newInputStream(file)) { // make a new, empty document Document doc = new Document(); // strip tags in here as they're unrequired //doc.add(new TextField("fullContents", new BufferedReader(new InputStreamReader(stream, StandardCharsets.UTF_8)))); // 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.toString(), Field.Store.YES); //System.out.println(pathField); String path = file.toString(); String pathContents = readFileToString(path, path, mappingPathToTitle); Field pathContents1 = new TextField("contents", pathContents, Field.Store.YES); if (!mappingPathToTitle.isEmpty()) { Field title = new TextField("title", mappingPathToTitle.get(path), Field.Store.YES); doc.add(title); } doc.add(pathField); doc.add(pathContents1); // 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", 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 (writer.getConfig().getOpenMode() == OpenMode.CREATE) { // New index, so we just add the document (no old document can be there): 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); writer.updateDocument(new Term("path", file.toString()), doc); } } } public static String readFileToString(String filePath, String pathField, HashMap<String, String> mappingPathToTitle) throws java.io.IOException { StringBuffer fileData = new StringBuffer(1000); BufferedReader reader = new BufferedReader(new FileReader(filePath)); char[] buf = new char[1024]; int numRead = 0; while ((numRead = reader.read(buf)) != -1) { String readData = String.valueOf(buf, 0, numRead); fileData.append(readData); buf = new char[1024]; } reader.close(); String fileContents = fileData.toString(); fileContents = html2text(fileContents, pathField, mappingPathToTitle); return fileContents; } public static String html2text(String html, String pathField, HashMap<String, String> mappingPathToTitle) { Pattern pattern = Pattern.compile("<TITLE>(.+?)</TITLE>"); Matcher matcher = pattern.matcher(html.toUpperCase()); if (matcher.find()) { mappingPathToTitle.put(pathField, matcher.group(1)); } return Jsoup.parse(html).text(); } }