惠州如何搜索Lucene索引的文件？_北大青鸟IT学校

如何搜索Lucene索引的文件？相信这是每个学习Java的同学都会遇到的问题，下面我们一起来看看惠州北大青鸟老师是怎么回答的。

实例

以下代码显示如何搜索Lucene索引的文件。

/*
* 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.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStreamReader;
import java.nio.charset.StandardCharsets;
import java.util.Date;

import org.apache.lucene.analysis.Analyzer;
import org.apache.lucene.analysis.standard.StandardAnalyzer;
import org.apache.lucene.document.Document;
import org.apache.lucene.index.DirectoryReader;
import org.apache.lucene.index.IndexReader;
import org.apache.lucene.queryparser.classic.QueryParser;
import org.apache.lucene.search.IndexSearcher;
import org.apache.lucene.search.Query;
import org.apache.lucene.search.ScoreDoc;
import org.apache.lucene.search.TopDocs;
import org.apache.lucene.store.FSDirectory;
import org.apache.lucene.util.Version;

/** Simple command-line based search demo. */public class Main {  private Main() {}
 /** Simple command-line based search demo. */  public static void main(String[] args) throws Exception {
   String usage =      "Usage:\tjava SearchFiles [-index dir] [-field f] [-repeat n] [-queries file] [-query string] [-raw] [-paging hitsPerPage]\n\nSee http://lucene.apache.org/core/4_1_0/demo/ for details.";    if (args.length > 0 && ("-h".equals(args[0]) || "-help".equals(args[0]))) {
     System.out.println(usage);
     System.exit(0);
   }

   String index = "index";
   String field = "contents";
   String queries = null;
   int repeat = 0;
   boolean raw = false;
   String queryString = null;
   int hitsPerPage = 10;    
   for(int i = 0;i < args.length;i++) {      if ("-index".equals(args[i])) {
       index = args[i+1];
       i++;
     } else if ("-field".equals(args[i])) {
       field = args[i+1];
       i++;
     } else if ("-queries".equals(args[i])) {
       queries = args[i+1];
       i++;
     } else if ("-query".equals(args[i])) {
       queryString = args[i+1];
       i++;
     } else if ("-repeat".equals(args[i])) {
       repeat = Integer.parseInt(args[i+1]);
       i++;
     } else if ("-raw".equals(args[i])) {
       raw = true;
     } else if ("-paging".equals(args[i])) {
       hitsPerPage = Integer.parseInt(args[i+1]);        if (hitsPerPage <= 0) {
         System.err.println("There must be at least 1 hit per page.");
         System.exit(1);
       }
       i++;
     }
   }
   
   IndexReader reader = DirectoryReader.open(FSDirectory.open(new File(index)));
   IndexSearcher searcher = new IndexSearcher(reader);
   // :Post-Release-Update-Version.LUCENE_XY:
   Analyzer analyzer = new StandardAnalyzer(Version.LUCENE_4_10_0);

   BufferedReader in = null;    if (queries != null) {
     in = new BufferedReader(new InputStreamReader(new FileInputStream(queries), StandardCharsets.UTF_8));
   } else {
     in = new BufferedReader(new InputStreamReader(System.in, StandardCharsets.UTF_8));
   }
   // :Post-Release-Update-Version.LUCENE_XY:
   QueryParser parser = new QueryParser(Version.LUCENE_4_10_0, field, analyzer);    while (true) {      if (queries == null && queryString == null) {                        // prompt the user
       System.out.println("Enter query: ");
     }

     String line = queryString != null ? queryString : in.readLine();      if (line == null || line.length() == -1) {        break;
     }

     line = line.trim();      if (line.length() == 0) {        break;
     }
     
     Query query = parser.parse(line);
     System.out.println("Searching for: " + query.toString(field));            
     if (repeat > 0) {                           // repeat & time as benchmark
       Date start = new Date();        for (int i = 0; i < repeat; i++) {
         searcher.search(query, null, 100);
       }
       Date end = new Date();
       System.out.println("Time: "+(end.getTime()-start.getTime())+"ms");
     }

     doPagingSearch(in, searcher, query, hitsPerPage, raw, queries == null && queryString == null);      if (queryString != null) {        break;
     }
   }
   reader.close();
 }

 /**
  * This demonstrates a typical paging search scenario, where the search engine presents
  * pages of size n to the user. The user can then go to the next page if interested in
  * the next hits.
  *
  * When the query is executed for the first time, then only enough results are collected
  * to fill 5 result pages. If the user wants to page beyond this limit, then the query
  * is executed another time and all hits are collected.
  *
  */  public static void doPagingSearch(BufferedReader in, IndexSearcher searcher, Query query,
                                    int hitsPerPage, boolean raw, boolean interactive) throws IOException {

   // Collect enough docs to show 5 pages
   TopDocs results = searcher.search(query, 5 * hitsPerPage);
   ScoreDoc[] hits = results.scoreDocs;
   
   int numTotalHits = results.totalHits;
   System.out.println(numTotalHits + " total matching documents");

   int start = 0;
   int end = Math.min(numTotalHits, hitsPerPage);        
   while (true) {      if (end > hits.length) {
       System.out.println("Only results 1 - " + hits.length +" of " + numTotalHits + " total matching documents collected.");
       System.out.println("Collect more (y/n) ?");
       String line = in.readLine();        if (line.length() == 0 || line.charAt(0) == "n") {          break;
       }

       hits = searcher.search(query, numTotalHits).scoreDocs;
     }
     
     end = Math.min(hits.length, start + hitsPerPage);      
     for (int i = start; i < end; i++) {        if (raw) {                              // output raw format
         System.out.println("doc="+hits[i].doc+" score="+hits[i].score);          continue;
       }

       Document doc = searcher.doc(hits[i].doc);
       String path = doc.get("path");        if (path != null) {
         System.out.println((i+1) + ". " + path);
         String title = doc.get("title");          if (title != null) {
           System.out.println("   Title: " + doc.get("title"));
         }
       } else {
         System.out.println((i+1) + ". " + "No path for this document");
       }
                 
     }      if (!interactive || end == 0) {        break;
     }      if (numTotalHits >= end) {
       boolean quit = false;        while (true) {
         System.out.print("Press ");          if (start - hitsPerPage >= 0) {
           System.out.print("(p)revious page, ");  
         }          if (start + hitsPerPage < numTotalHits) {
           System.out.print("(n)ext page, ");
         }
         System.out.println("(q)uit or enter number to jump to a page.");
         
         String line = in.readLine();          if (line.length() == 0 || line.charAt(0)=="q") {
           quit = true;            break;
         }          if (line.charAt(0) == "p") {
           start = Math.max(0, start - hitsPerPage);            break;
         } else if (line.charAt(0) == "n") {            if (start + hitsPerPage < numTotalHits) {
             start+=hitsPerPage;
           }            break;
         } else {
           int page = Integer.parseInt(line);            if ((page - 1) * hitsPerPage < numTotalHits) {
             start = (page - 1) * hitsPerPage;              break;
           } else {
             System.out.println("No such page");
           }
         }
       }        if (quit) break;
       end = Math.min(numTotalHits, start + hitsPerPage);
     }
   }
 }
}

想了解更多关于Java的资讯吗？可以来惠州北大青鸟新方舟校区了解一下。

Java

标签：惠州计算机JAVA软件开发惠州计算机Java软件开发惠州计算机JAVA培训惠州计算机JAVA软件开发学校惠州计算机Java软件开发培训JAVAJava软件开发北大青鸟IT计算机学校北大青鸟IT软件学校北大青鸟IT学校