lucene 使用示例

Lucene是一个开源的全文搜索引擎库，用于实现文本索引和搜索功能。下面是一个Lucene的使用示例:

1. 创建索引:

import org.apache.lucene.analysis.Analyzer;
import org.apache.lucene.analysis.standard.StandardAnalyzer;
import org.apache.lucene.document.Document;
import org.apache.lucene.document.Field;
import org.apache.lucene.index.IndexWriter;
import org.apache.lucene.index.IndexWriterConfig;
import org.apache.lucene.store.Directory;
import org.apache.lucene.store.FSDirectory;

// 创建索引
public class Indexer {
    public static void main(String[] args) {
        // 索引存储路径
        String indexPath = "path_to_index_directory";

        try {
            // 创建分词器
            Analyzer analyzer = new StandardAnalyzer();

            // 创建索引配置
            IndexWriterConfig config = new IndexWriterConfig(analyzer);

            // 创建索引目录
            Directory directory = FSDirectory.open(Paths.get(indexPath));

            // 创建索引写入器
            IndexWriter indexWriter = new IndexWriter(directory, config);

            // 创建文档
            Document document = new Document();
            document.add(new Field("content", "Hello world!", TextField.TYPE_STORED));

            // 将文档添加到索引中
            indexWriter.addDocument(document);

            // 提交索引
            indexWriter.commit();

            // 关闭索引写入器
            indexWriter.close();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

2. 搜索索引:

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.Directory;
import org.apache.lucene.store.FSDirectory;

// 搜索索引
public class Searcher {
    public static void main(String[] args) {
        // 索引目录路径
        String indexPath = "path_to_index_directory";

        try {
            // 创建分词器
            Analyzer analyzer = new StandardAnalyzer();

            // 创建索引目录
            Directory directory = FSDirectory.open(Paths.get(indexPath));

            // 创建索引读取器
            IndexReader indexReader = DirectoryReader.open(directory);

            // 创建索引搜索器
            IndexSearcher indexSearcher = new IndexSearcher(indexReader);

            // 创建查询解析器
            QueryParser parser = new QueryParser("content", analyzer);

            // 创建查询
            Query query = parser.parse("Hello");

            // 执行查询，获取前n个结果
            TopDocs topDocs = indexSearcher.search(query, 10);
            ScoreDoc[] scoreDocs = topDocs.scoreDocs;

            // 遍历结果
            for (ScoreDoc scoreDoc : scoreDocs) {
                int docId = scoreDoc.doc;
                Document document = indexSearcher.doc(docId);
                System.out.println("Content: " + document.get("content"));
            }

            // 关闭索引读取器
            indexReader.close();
        } catch (IOException | ParseException e) {
            e.printStackTrace();
        }
    }
}

以上示例演示了如何使用Lucene创建索引并进行搜索。在创建索引时，需要定义分词器、索引配置、文档字段等。在搜索索引时，需要创建查询解析器、执行查询并获取结果。你可以根据自己的需求进行更多的定制和优化。