Java tutorial
package org.bidtime.lucene.utils; /* * 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.File; import java.io.FileInputStream; import java.io.FileNotFoundException; import java.io.IOException; 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.index.IndexWriter; import org.apache.lucene.index.IndexWriterConfig.OpenMode; import org.apache.lucene.index.Term; /** * 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 { private IndexFiles() { } /** Index all text files under a directory. */ // public static void main(String[] args) { // String usage = "java org.apache.lucene.demo.IndexFiles" // + " [-index INDEX_PATH] [-docs DOCS_PATH] [-update]\n\n" // + "This indexes the documents in DOCS_PATH, creating a Lucene index" // + "in INDEX_PATH that can be searched with SearchFiles"; // boolean create = true; // String indexPath = "index"; // String docsPath = null; // for (int i = 0; i < args.length; i++) { // if ("-index".equals(args[i])) { // indexPath = args[i + 1]; // i++; // } else if ("-docs".equals(args[i])) { // docsPath = args[i + 1]; // i++; // } else if ("-update".equals(args[i])) { // create = false; // } // } // // if (docsPath == null) { // System.err.println("Usage: " + usage); // System.exit(1); // } // indexit(indexPath, docsPath, create); // } // public static void main(String[] args) { // boolean create = true; // String indexPath = "D:/DATA/index3"; // String docsPath = "D:/DATA/source3"; // indexit(indexPath, docsPath, create); // } // @SuppressWarnings("deprecation") // private static void indexit(String indexPath, String docsPath, boolean create) { // final File docDir = new File(docsPath); // if (!docDir.exists() || !docDir.canRead()) { // System.out // .println("Document directory '" // + docDir.getAbsolutePath() // + "' 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)); // // :Post-Release-Update-Version.LUCENE_XY: // Analyzer analyzer = new StandardAnalyzer(); // 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 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 */ 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.NO); doc.add(pathField); // 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. // doc.add(new TextField("contents", new BufferedReader( // new InputStreamReader(fis, StandardCharsets.UTF_8)))); 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); writer.updateDocument(new Term("path", file.getPath()), doc); } } finally { fis.close(); } } } } }