Lucene的基本应用

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import java.io.File;import java.io.IOException;import java.util.ArrayList;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.Field;import org.apache.lucene.document.Field.Index;import org.apache.lucene.document.Field.Store;import org.apache.lucene.index.IndexWriter;import org.apache.lucene.index.IndexWriter.MaxFieldLength;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.TopDocs;import org.apache.lucene.store.Directory;import org.apache.lucene.store.FSDirectory;import org.apache.lucene.util.Version;import org.junit.Test;import cn.itcast._domain.Article;public class HelloWorld { private static Directory directory; // 索引库目录 private static Analyzer analyzer; // 分词器 static { try { directory = FSDirectory.open(new File("./indexDir")); analyzer = new StandardAnalyzer(Version.LUCENE_30); } catch (IOException e) { throw new RuntimeException(e); } } // 建立索引 @Test public void testCreateIndex() throws Exception { // 准备数据 Article article = new Article(); article.setId(1); article.setTitle("准备Lucene的开发环境"); article.setContent("如果信息检索系统在用户发出了检索请求后再去互联网上找答案,根本无法在有限的时间内返回结果。"); // 放到索引库中 // 1, 把Article转为Document Document doc = new Document(); String idStr = article.getId().toString(); doc.add(new Field("id", idStr, Store.YES, Index.NOT_ANALYZED)); doc.add(new Field("title", article.getTitle(), Store.YES, Index.ANALYZED)); doc.add(new Field("content", article.getContent(), Store.NO, Index.ANALYZED)); // 2, 把Document放到索引库中 IndexWriter indexWriter = new IndexWriter(directory, analyzer, MaxFieldLength.UNLIMITED); indexWriter.addDocument(doc); indexWriter.close(); } // 搜索 @Test public void testSearch() throws Exception { // 准备查询条件 String queryString = "lucene"; // String queryString = "hibernate"; // 执行搜索 List<Article> list = new ArrayList<Article>(); // ========================================================================================== // 1,把查询字符串转为Query对象(默认只从title中查询) QueryParser queryParser = new QueryParser(Version.LUCENE_30, "title", analyzer); Query query = queryParser.parse(queryString); // 2,执行查询,得到中间结果 IndexSearcher indexSearcher = new IndexSearcher(directory); // 指定所用的索引库 TopDocs topDocs = indexSearcher.search(query, 100); // 最多返回前n条结果 int count = topDocs.totalHits; ScoreDoc[] scoreDocs = topDocs.scoreDocs; // 3,处理结果 for (int i = 0; i < scoreDocs.length; i++) { ScoreDoc scoreDoc = scoreDocs[i]; float score = scoreDoc.score; // 相关度得分 int docId = scoreDoc.doc; // Document的内部编号 // 根据编号拿到Document数据 Document doc = indexSearcher.doc(docId); // 把Document转为Article String idStr = doc.getField("id").toString(); //doc.get("id"); String title = doc.get("title"); String content = doc.get("content"); // 等价于 doc.getField("content").stringValue(); Article article = new Article(); article.setId(Integer.parseInt(idStr)); article.setTitle(title); article.setContent(content); list.add(article); } indexSearcher.close(); // ========================================================================================== // 显示结果 System.out.println("总结果数:" + list.size()); for (Article a : list) { System.out.println("------------------------------"); System.out.println("id = " + a.getId()); System.out.println("title = " + a.getTitle()); System.out.println("content = " + a.getContent()); } }}


public class Article { private Integer id; private String title; private String content; public Integer getId() { return id; } public void setId(Integer id) { this.id = id; } public String getTitle() { return title; } public void setTitle(String title) { this.title = title; } public String getContent() { return content; } public void setContent(String content) { this.content = content; }}





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