Lucene全文检索的【增、删、改、查】 实例

2022-06-07 12:38:37

　　创建索引

Lucene在进行创建索引时，根据前面一篇博客，已经讲完了大体的流程，这里再简单说下：

Directory directory = FSDirectory.open("/tmp/testindex");

IndexWriterConfig config = new IndexWriterConfig(Version.LUCENE_CURRENT, analyzer);

IndexWriter iwriter = new IndexWriter(directory, config);

Document doc = new Document();

String text = "This is the text to be indexed.";

doc.add(new Field("fieldname", text, TextField.TYPE_STORED)); iwriter.close();

　　1 创建Directory，获取索引目录

　　2 创建词法分析器，创建IndexWriter对象

　　3 创建document对象，存储数据

　　4 关闭IndexWriter，提交

/**

     * 建立索引

     *

     * @param args

     */

    public static void index() throws Exception {

        String text1 = "hello,man!";

        String text2 = "goodbye,man!";

        String text3 = "hello,woman!";

        String text4 = "goodbye,woman!";

        Date date1 = new Date();

        analyzer = new StandardAnalyzer(Version.LUCENE_CURRENT);

        directory = FSDirectory.open(new File(INDEX_DIR));

        IndexWriterConfig config = new IndexWriterConfig(

                Version.LUCENE_CURRENT, analyzer);

        indexWriter = new IndexWriter(directory, config);

        Document doc1 = new Document();

        doc1.add(new TextField("filename", "text1", Store.YES));

        doc1.add(new TextField("content", text1, Store.YES));

        indexWriter.addDocument(doc1);

        Document doc2 = new Document();

        doc2.add(new TextField("filename", "text2", Store.YES));

        doc2.add(new TextField("content", text2, Store.YES));

        indexWriter.addDocument(doc2);

        Document doc3 = new Document();

        doc3.add(new TextField("filename", "text3", Store.YES));

        doc3.add(new TextField("content", text3, Store.YES));

        indexWriter.addDocument(doc3);

        Document doc4 = new Document();

        doc4.add(new TextField("filename", "text4", Store.YES));

        doc4.add(new TextField("content", text4, Store.YES));

        indexWriter.addDocument(doc4);

        indexWriter.commit();

        indexWriter.close();

        Date date2 = new Date();

        System.out.println("创建索引耗时：" + (date2.getTime() - date1.getTime()) + "ms\n");

    }

　　增量添加索引

Lucene拥有增量添加索引的功能，在不会影响之前的索引情况下，添加索引，它会在何时的时机，自动合并索引文件。

/**

     * 增加索引

     *

     * @throws Exception

     */

    public static void insert() throws Exception {

        String text5 = "hello,goodbye,man,woman";

        Date date1 = new Date();

        analyzer = new StandardAnalyzer(Version.LUCENE_CURRENT);

        directory = FSDirectory.open(new File(INDEX_DIR));

        IndexWriterConfig config = new IndexWriterConfig(

                Version.LUCENE_CURRENT, analyzer);

        indexWriter = new IndexWriter(directory, config);

        Document doc1 = new Document();

        doc1.add(new TextField("filename", "text5", Store.YES));

        doc1.add(new TextField("content", text5, Store.YES));

        indexWriter.addDocument(doc1);

        indexWriter.commit();

        indexWriter.close();

        Date date2 = new Date();

        System.out.println("增加索引耗时：" + (date2.getTime() - date1.getTime()) + "ms\n");

    }

　　删除索引

Lucene也是通过IndexWriter调用它的delete方法，来删除索引。我们可以通过关键字，删除与这个关键字有关的所有内容。如果仅仅是想要删除一个文档，那么最好就顶一个唯一的ID域，通过这个ID域，来进行删除操作。

/**

     * 删除索引

     *

     * @param str 删除的关键字

     * @throws Exception

     */

    public static void delete(String str) throws Exception {

        Date date1 = new Date();

        analyzer = new StandardAnalyzer(Version.LUCENE_CURRENT);

        directory = FSDirectory.open(new File(INDEX_DIR));

        IndexWriterConfig config = new IndexWriterConfig(

                Version.LUCENE_CURRENT, analyzer);

        indexWriter = new IndexWriter(directory, config);

        indexWriter.deleteDocuments(new Term("filename",str));  

        indexWriter.close();

        Date date2 = new Date();

        System.out.println("删除索引耗时：" + (date2.getTime() - date1.getTime()) + "ms\n");

    }

　　更新索引

Lucene没有真正的更新操作，通过某个fieldname，可以更新这个域对应的索引，但是实质上，它是先删除索引，再重新建立的。

/**

     * 更新索引

     *

     * @throws Exception

     */

    public static void update() throws Exception {

        String text1 = "update,hello,man!";

        Date date1 = new Date();

         analyzer = new StandardAnalyzer(Version.LUCENE_CURRENT);

         directory = FSDirectory.open(new File(INDEX_DIR));

         IndexWriterConfig config = new IndexWriterConfig(

                 Version.LUCENE_CURRENT, analyzer);

         indexWriter = new IndexWriter(directory, config);

         Document doc1 = new Document();

        doc1.add(new TextField("filename", "text1", Store.YES));

        doc1.add(new TextField("content", text1, Store.YES));

        indexWriter.updateDocument(new Term("filename","text1"), doc1);

         indexWriter.close();

         Date date2 = new Date();

         System.out.println("更新索引耗时：" + (date2.getTime() - date1.getTime()) + "ms\n");

    }

　　通过索引查询关键字

Lucene的查询方式有很多种，这里就不做详细介绍了。它会返回一个ScoreDoc的集合，类似ResultSet的集合，我们可以通过域名获取想要获取的内容。

/**

     * 关键字查询

     *

     * @param str

     * @throws Exception

     */

    public static void search(String str) throws Exception {

        directory = FSDirectory.open(new File(INDEX_DIR));

        analyzer = new StandardAnalyzer(Version.LUCENE_CURRENT);

        DirectoryReader ireader = DirectoryReader.open(directory);

        IndexSearcher isearcher = new IndexSearcher(ireader);

        QueryParser parser = new QueryParser(Version.LUCENE_CURRENT, "content",analyzer);

        Query query = parser.parse(str);

        ScoreDoc[] hits = isearcher.search(query, null, 1000).scoreDocs;

        for (int i = 0; i < hits.length; i++) {

            Document hitDoc = isearcher.doc(hits[i].doc);

            System.out.println(hitDoc.get("filename"));

            System.out.println(hitDoc.get("content"));

        }

        ireader.close();

        directory.close();

    }

　　全部代码

package test;

import java.io.File;

import java.util.Date;

import java.util.List;

import org.apache.lucene.analysis.Analyzer;

import org.apache.lucene.analysis.standard.StandardAnalyzer;

import org.apache.lucene.document.Document;

import org.apache.lucene.document.LongField;

import org.apache.lucene.document.TextField;

import org.apache.lucene.document.Field.Store;

import org.apache.lucene.index.DirectoryReader;

import org.apache.lucene.index.IndexWriter;

import org.apache.lucene.index.IndexWriterConfig;

import org.apache.lucene.index.Term;

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.store.Directory;

import org.apache.lucene.store.FSDirectory;

import org.apache.lucene.util.Version;

public class TestLucene {

    // 保存路径

    private static String INDEX_DIR = "D:\\luceneIndex";

    private static Analyzer analyzer = null;

    private static Directory directory = null;

    private static IndexWriter indexWriter = null;

    public static void main(String[] args) {

        try {

//            index();

            search("man");

//            insert();

//            delete("text5");

//            update();

        } catch (Exception e) {

            e.printStackTrace();

        }

    }

    /**

     * 更新索引

     *

     * @throws Exception

     */

    public static void update() throws Exception {

        String text1 = "update,hello,man!";

        Date date1 = new Date();

         analyzer = new StandardAnalyzer(Version.LUCENE_CURRENT);

         directory = FSDirectory.open(new File(INDEX_DIR));

         IndexWriterConfig config = new IndexWriterConfig(

                 Version.LUCENE_CURRENT, analyzer);

         indexWriter = new IndexWriter(directory, config);

         Document doc1 = new Document();

        doc1.add(new TextField("filename", "text1", Store.YES));

        doc1.add(new TextField("content", text1, Store.YES));

        indexWriter.updateDocument(new Term("filename","text1"), doc1);

         indexWriter.close();

         Date date2 = new Date();

         System.out.println("更新索引耗时：" + (date2.getTime() - date1.getTime()) + "ms\n");

    }

    /**

     * 删除索引

     *

     * @param str 删除的关键字

     * @throws Exception

     */

    public static void delete(String str) throws Exception {

        Date date1 = new Date();

        analyzer = new StandardAnalyzer(Version.LUCENE_CURRENT);

        directory = FSDirectory.open(new File(INDEX_DIR));

        IndexWriterConfig config = new IndexWriterConfig(

                Version.LUCENE_CURRENT, analyzer);

        indexWriter = new IndexWriter(directory, config);

        indexWriter.deleteDocuments(new Term("filename",str));  

        indexWriter.close();

        Date date2 = new Date();

        System.out.println("删除索引耗时：" + (date2.getTime() - date1.getTime()) + "ms\n");

    }

    /**

     * 增加索引

     *

     * @throws Exception

     */

    public static void insert() throws Exception {

        String text5 = "hello,goodbye,man,woman";

        Date date1 = new Date();

        analyzer = new StandardAnalyzer(Version.LUCENE_CURRENT);

        directory = FSDirectory.open(new File(INDEX_DIR));

        IndexWriterConfig config = new IndexWriterConfig(

                Version.LUCENE_CURRENT, analyzer);

        indexWriter = new IndexWriter(directory, config);

        Document doc1 = new Document();

        doc1.add(new TextField("filename", "text5", Store.YES));

        doc1.add(new TextField("content", text5, Store.YES));

        indexWriter.addDocument(doc1);

        indexWriter.commit();

        indexWriter.close();

        Date date2 = new Date();

        System.out.println("增加索引耗时：" + (date2.getTime() - date1.getTime()) + "ms\n");

    }

    /**

     * 建立索引

     *

     * @param args

     */

    public static void index() throws Exception {

        String text1 = "hello,man!";

        String text2 = "goodbye,man!";

        String text3 = "hello,woman!";

        String text4 = "goodbye,woman!";

        Date date1 = new Date();

        analyzer = new StandardAnalyzer(Version.LUCENE_CURRENT);

        directory = FSDirectory.open(new File(INDEX_DIR));

        IndexWriterConfig config = new IndexWriterConfig(

                Version.LUCENE_CURRENT, analyzer);

        indexWriter = new IndexWriter(directory, config);

        Document doc1 = new Document();

        doc1.add(new TextField("filename", "text1", Store.YES));

        doc1.add(new TextField("content", text1, Store.YES));

        indexWriter.addDocument(doc1);

        Document doc2 = new Document();

        doc2.add(new TextField("filename", "text2", Store.YES));

        doc2.add(new TextField("content", text2, Store.YES));

        indexWriter.addDocument(doc2);

        Document doc3 = new Document();

        doc3.add(new TextField("filename", "text3", Store.YES));

        doc3.add(new TextField("content", text3, Store.YES));

        indexWriter.addDocument(doc3);

        Document doc4 = new Document();

        doc4.add(new TextField("filename", "text4", Store.YES));

        doc4.add(new TextField("content", text4, Store.YES));

        indexWriter.addDocument(doc4);

        indexWriter.commit();

        indexWriter.close();

        Date date2 = new Date();

        System.out.println("创建索引耗时：" + (date2.getTime() - date1.getTime()) + "ms\n");

    }

    /**

     * 关键字查询

     *

     * @param str

     * @throws Exception

     */

    public static void search(String str) throws Exception {

        directory = FSDirectory.open(new File(INDEX_DIR));

        analyzer = new StandardAnalyzer(Version.LUCENE_CURRENT);

        DirectoryReader ireader = DirectoryReader.open(directory);

        IndexSearcher isearcher = new IndexSearcher(ireader);

        QueryParser parser = new QueryParser(Version.LUCENE_CURRENT, "content",analyzer);

        Query query = parser.parse(str);

        ScoreDoc[] hits = isearcher.search(query, null, 1000).scoreDocs;

        for (int i = 0; i < hits.length; i++) {

            Document hitDoc = isearcher.doc(hits[i].doc);

            System.out.println(hitDoc.get("filename"));

            System.out.println(hitDoc.get("content"));

        }

        ireader.close();

        directory.close();

    }

}
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