Java tutorial
package com.sg.business.vault.index.demo; /* * 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 java.util.Date; import org.apache.lucene.analysis.Analyzer; import org.apache.lucene.analysis.cn.smart.SmartChineseAnalyzer; import org.apache.lucene.document.Document; import org.apache.lucene.document.Field; 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 com.mobnut.commons.util.file.FileUtil; /** 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" //$NON-NLS-1$ + " [-index INDEX_PATH] [-docs DOCS_PATH] [-update]\n\n" //$NON-NLS-1$ + "This indexes the documents in DOCS_PATH, creating a Lucene index" //$NON-NLS-1$ + "in INDEX_PATH that can be searched with SearchFiles"; //$NON-NLS-1$ String indexPath = "index"; //$NON-NLS-1$ String docsPath = null; boolean create = true; for (int i = 0; i < args.length; i++) { if ("-index".equals(args[i])) { //$NON-NLS-1$ indexPath = args[i + 1]; i++; } else if ("-docs".equals(args[i])) { //$NON-NLS-1$ docsPath = args[i + 1]; i++; } else if ("-update".equals(args[i])) { //$NON-NLS-1$ create = false; } } if (docsPath == null) { System.err.println("Usage: " + usage); //$NON-NLS-1$ System.exit(1); } final File docDir = new File(docsPath); if (!docDir.exists() || !docDir.canRead()) { System.out.println("Document directory '" + docDir.getAbsolutePath() //$NON-NLS-1$ + "' does not exist or is not readable, please check the path"); //$NON-NLS-1$ System.exit(1); } Date start = new Date(); try { System.out.println("Indexing to directory '" + indexPath + "'..."); //$NON-NLS-1$ //$NON-NLS-2$ Directory dir = FSDirectory.open(new File(indexPath)); Analyzer analyzer = new SmartChineseAnalyzer(Version.LUCENE_44); IndexWriterConfig iwc = new IndexWriterConfig(Version.LUCENE_44, 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"); //$NON-NLS-1$ } catch (IOException e) { System.out.println(" caught a " + e.getClass() + //$NON-NLS-1$ "\n with message: " + e.getMessage()); //$NON-NLS-1$ } } /** * 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.YES); //$NON-NLS-1$ 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, "UTF-8")))); try { doc.add(new TextField("contents", FileUtil.getContent(file.getName(), fis), //$NON-NLS-1$ Field.Store.NO)); } catch (Exception e) { e.printStackTrace(); } 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); //$NON-NLS-1$ 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); //$NON-NLS-1$ writer.updateDocument(new Term("path", file.getPath()), doc); //$NON-NLS-1$ } } finally { fis.close(); } } } } }