indexfiles.java

lucene实现全文检索的实际小例子,可以实现对文本文件的检索,和对内容的查询.! lucene实现全文检索的实际小例子,可以实现对文本文件的检索,和对内容的查询.!

package org.apache.lucene.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 org.apache.lucene.analysis.standard.StandardAnalyzer;
import org.apache.lucene.index.IndexWriter;

import java.io.File;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.util.Date;

/** Index all text files under a directory. */
public class IndexFiles {
  
  private IndexFiles() {}

  static final File INDEX_DIR = new File("index");
  
  /** Index all text files under a directory. */
  public static void main(String[] args) {
    String usage = "java org.apache.lucene.demo.IndexFiles <root_directory>";
    if (args.length == 0) {
      System.err.println("Usage: " + usage);
      System.exit(1);
    }

    if (INDEX_DIR.exists()) {
      System.out.println("Cannot save index to '" +INDEX_DIR+ "' directory, please delete it first");
      System.exit(1);
    }
    
    final File docDir = new File(args[0]);
    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 {
      IndexWriter writer = new IndexWriter(INDEX_DIR, new StandardAnalyzer(), true, IndexWriter.MaxFieldLength.LIMITED);
      System.out.println("Indexing to directory '" +INDEX_DIR+ "'...");
      indexDocs(writer, docDir);
      System.out.println("Optimizing...");
      writer.optimize();
      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());
    }
  }

  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 {
        System.out.println("adding " + file);
        try {
          writer.addDocument(FileDocument.Document(file));
        }
        // 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
        catch (FileNotFoundException fnfe) {
          ;
        }
      }
    }
  }
  
}