Lucene 简明教程

Lucene - Sorting

在本章中，我们将了解 Lucene 在默认情况下提供的或者可以根据需要进行处理的搜索结果的排序顺序。

Sorting by Relevance

这是 Lucene 使用的默认排序模式。Lucene 根据最相关的点击结果提供结果。

private void sortUsingRelevance(String searchQuery)
   throws IOException, ParseException {
   searcher = new Searcher(indexDir);
   long startTime = System.currentTimeMillis();

   //create a term to search file name
   Term term = new Term(LuceneConstants.FILE_NAME, searchQuery);
   //create the term query object
   Query query = new FuzzyQuery(term);
   searcher.setDefaultFieldSortScoring(true, false);
   //do the search
   TopDocs hits = searcher.search(query,Sort.RELEVANCE);
   long endTime = System.currentTimeMillis();

   System.out.println(hits.totalHits +
      " documents found. Time :" + (endTime - startTime) + "ms");
   for(ScoreDoc scoreDoc : hits.scoreDocs) {
      Document doc = searcher.getDocument(scoreDoc);
      System.out.print("Score: "+ scoreDoc.score + " ");
      System.out.println("File: "+ doc.get(LuceneConstants.FILE_PATH));
   }
   searcher.close();
}

Sorting by IndexOrder

Lucene 使用该排序模式。在此处，将首先在搜索结果中显示首次编入索引的文档。

private void sortUsingIndex(String searchQuery)
   throws IOException, ParseException {
   searcher = new Searcher(indexDir);
   long startTime = System.currentTimeMillis();

   //create a term to search file name
   Term term = new Term(LuceneConstants.FILE_NAME, searchQuery);
   //create the term query object
   Query query = new FuzzyQuery(term);
   searcher.setDefaultFieldSortScoring(true, false);
   //do the search
   TopDocs hits = searcher.search(query,Sort.INDEXORDER);
   long endTime = System.currentTimeMillis();

   System.out.println(hits.totalHits +
      " documents found. Time :" + (endTime - startTime) + "ms");
   for(ScoreDoc scoreDoc : hits.scoreDocs) {
      Document doc = searcher.getDocument(scoreDoc);
      System.out.print("Score: "+ scoreDoc.score + " ");
      System.out.println("File: "+ doc.get(LuceneConstants.FILE_PATH));
   }
   searcher.close();
}

Example Application

让我们创建一个测试 Lucene 应用程序来测试排序过程。

Step	Description
1	在包 com.tutorialspoint.lucene 下使用名称 LuceneFirstApplication 创建一个项目，如 Lucene - 第一个应用程序章节中所述。您还可以在此章节中使用如该章节中创建的项目，以便理解搜索过程。
2	创建 LuceneConstants.java 和 Searcher.java，如 Lucene - 第一章应用程序中所述。保持其余文件不变。
3	如下所示创建 LuceneTester.java。
4	清理并构建应用程序以确保业务逻辑按照要求正常工作。

LuceneConstants.java

此类用于提供将在整个示例应用程序中使用的各种常量。

package com.tutorialspoint.lucene;

public class LuceneConstants {
   public static final String CONTENTS = "contents";
   public static final String FILE_NAME = "filename";
   public static final String FILE_PATH = "filepath";
   public static final int MAX_SEARCH = 10;
}

Searcher.java

此类用于读取原始数据上创建的索引并使用 Lucene 库搜索数据。

package com.tutorialspoint.lucene;

import java.io.File;
import java.io.IOException;

import org.apache.lucene.analysis.standard.StandardAnalyzer;
import org.apache.lucene.document.Document;
import org.apache.lucene.index.CorruptIndexException;
import org.apache.lucene.queryParser.ParseException;
import org.apache.lucene.queryParser.QueryParser;
import org.apache.lucene.search.IndexSearcher;
import org.apache.lucene.search.Query;
import org.apache.lucene.search.ScoreDoc;
import org.apache.lucene.search.Sort;
import org.apache.lucene.search.TopDocs;
import org.apache.lucene.store.Directory;
import org.apache.lucene.store.FSDirectory;
import org.apache.lucene.util.Version;

public class Searcher {

IndexSearcher indexSearcher;
   QueryParser queryParser;
   Query query;

   public Searcher(String indexDirectoryPath) throws IOException {
      Directory indexDirectory
         = FSDirectory.open(new File(indexDirectoryPath));
      indexSearcher = new IndexSearcher(indexDirectory);
      queryParser = new QueryParser(Version.LUCENE_36,
         LuceneConstants.CONTENTS,
         new StandardAnalyzer(Version.LUCENE_36));
   }

   public TopDocs search( String searchQuery)
      throws IOException, ParseException {
      query = queryParser.parse(searchQuery);
      return indexSearcher.search(query, LuceneConstants.MAX_SEARCH);
   }

   public TopDocs search(Query query)
      throws IOException, ParseException {
      return indexSearcher.search(query, LuceneConstants.MAX_SEARCH);
   }

   public TopDocs search(Query query,Sort sort)
      throws IOException, ParseException {
      return indexSearcher.search(query,
         LuceneConstants.MAX_SEARCH,sort);
   }

   public void setDefaultFieldSortScoring(boolean doTrackScores,
      boolean doMaxScores) {
      indexSearcher.setDefaultFieldSortScoring(
         doTrackScores,doMaxScores);
   }

   public Document getDocument(ScoreDoc scoreDoc)
      throws CorruptIndexException, IOException {
      return indexSearcher.doc(scoreDoc.doc);
   }

   public void close() throws IOException {
      indexSearcher.close();
   }
}

LuceneTester.java

此类用于测试 Lucene 库的搜索功能。

package com.tutorialspoint.lucene;

import java.io.IOException;

import org.apache.lucene.document.Document;
import org.apache.lucene.index.Term;
import org.apache.lucene.queryParser.ParseException;
import org.apache.lucene.search.FuzzyQuery;
import org.apache.lucene.search.Query;
import org.apache.lucene.search.ScoreDoc;
import org.apache.lucene.search.Sort;
import org.apache.lucene.search.TopDocs;

public class LuceneTester {

   String indexDir = "E:\\Lucene\\Index";
   String dataDir = "E:\\Lucene\\Data";
   Indexer indexer;
   Searcher searcher;

   public static void main(String[] args) {
      LuceneTester tester;
      try {
          tester = new LuceneTester();
          tester.sortUsingRelevance("cord3.txt");
          tester.sortUsingIndex("cord3.txt");
      } catch (IOException e) {
          e.printStackTrace();
      } catch (ParseException e) {
          e.printStackTrace();
      }
   }

   private void sortUsingRelevance(String searchQuery)
      throws IOException, ParseException {
      searcher = new Searcher(indexDir);
      long startTime = System.currentTimeMillis();

      //create a term to search file name
      Term term = new Term(LuceneConstants.FILE_NAME, searchQuery);
      //create the term query object
      Query query = new FuzzyQuery(term);
      searcher.setDefaultFieldSortScoring(true, false);
      //do the search
      TopDocs hits = searcher.search(query,Sort.RELEVANCE);
      long endTime = System.currentTimeMillis();

      System.out.println(hits.totalHits +
         " documents found. Time :" + (endTime - startTime) + "ms");
      for(ScoreDoc scoreDoc : hits.scoreDocs) {
         Document doc = searcher.getDocument(scoreDoc);
         System.out.print("Score: "+ scoreDoc.score + " ");
         System.out.println("File: "+ doc.get(LuceneConstants.FILE_PATH));
      }
      searcher.close();
   }

   private void sortUsingIndex(String searchQuery)
      throws IOException, ParseException {
      searcher = new Searcher(indexDir);
      long startTime = System.currentTimeMillis();
      //create a term to search file name
      Term term = new Term(LuceneConstants.FILE_NAME, searchQuery);
      //create the term query object
      Query query = new FuzzyQuery(term);
      searcher.setDefaultFieldSortScoring(true, false);
      //do the search
      TopDocs hits = searcher.search(query,Sort.INDEXORDER);
      long endTime = System.currentTimeMillis();

      System.out.println(hits.totalHits +
      " documents found. Time :" + (endTime - startTime) + "ms");
      for(ScoreDoc scoreDoc : hits.scoreDocs) {
         Document doc = searcher.getDocument(scoreDoc);
         System.out.print("Score: "+ scoreDoc.score + " ");
         System.out.println("File: "+ doc.get(LuceneConstants.FILE_PATH));
      }
      searcher.close();
   }
}

Data & Index Directory Creation

我们已使用 10 个文本文件（record1.txt 到 record10.txt），其中包含学生姓名和其他详细信息，并将它们放在 E:\Lucene\Data. Test Data 目录中。应将索引目录路径创建为 E:\Lucene\Index。在本章的 Lucene - Indexing Process 中运行索引程序后，您可以在该文件夹中看到创建的索引文件列表。

Running the Program

创建完源代码、原始数据、数据目录、索引目录和索引后，您可以编译并运行程序。为此，保持 LuceneTester.Java 文件选项卡处于活动状态，然后使用 Eclipse IDE 中的“运行”选项，或使用 Ctrl + F11 编译并运行 LuceneTester 应用程序。如果您的应用程序运行成功，它将在 Eclipse IDE 的控制台中打印以下消息：

10 documents found. Time :31ms
Score: 1.3179655 File: E:\Lucene\Data\record3.txt
Score: 0.790779 File: E:\Lucene\Data\record1.txt
Score: 0.790779 File: E:\Lucene\Data\record2.txt
Score: 0.790779 File: E:\Lucene\Data\record4.txt
Score: 0.790779 File: E:\Lucene\Data\record5.txt
Score: 0.790779 File: E:\Lucene\Data\record6.txt
Score: 0.790779 File: E:\Lucene\Data\record7.txt
Score: 0.790779 File: E:\Lucene\Data\record8.txt
Score: 0.790779 File: E:\Lucene\Data\record9.txt
Score: 0.2635932 File: E:\Lucene\Data\record10.txt
10 documents found. Time :0ms
Score: 0.790779 File: E:\Lucene\Data\record1.txt
Score: 0.2635932 File: E:\Lucene\Data\record10.txt
Score: 0.790779 File: E:\Lucene\Data\record2.txt
Score: 1.3179655 File: E:\Lucene\Data\record3.txt
Score: 0.790779 File: E:\Lucene\Data\record4.txt
Score: 0.790779 File: E:\Lucene\Data\record5.txt
Score: 0.790779 File: E:\Lucene\Data\record6.txt
Score: 0.790779 File: E:\Lucene\Data\record7.txt
Score: 0.790779 File: E:\Lucene\Data\record8.txt
Score: 0.790779 File: E:\Lucene\Data\record9.txt