xuyan5971

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");//索引止錄。建在當(dāng)前目錄的/index下
 
  /** Index all text files under a directory. */
  public static void main(String[] args) {//args[0] 文件路徑.  main 方法：對args[0]指定的文件路徑下的所有文件建立索引。
  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);
   //IndexWriter負責(zé)創(chuàng)建和維護索引
   //IndexWriter(String path, Analyzer a, boolean create, IndexWriter.MaxFieldLength mfl)
   //path:路徑 Analyzer:文本分析器  create:是否創(chuàng)建新索引  mfl 最大field數(shù)量
   System.out.println("Indexing to directory '" + INDEX_DIR + "'...");
   indexDocs(writer, docDir);
   System.out.println("Optimizing...");
   writer.optimize();//優(yōu)化索引
   writer.close();//關(guān)閉
   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) {
     ;
    }
   }
  }
 }
}