第一章：初识lucene

朱雀 2022-08-06 11:19 214阅读 0赞

lucene实战程序示例：

## 建立索引（使用Indexer索引文本文件） ##

package lucene;
    
    import java.io.File;
    import java.io.FileFilter;
    import java.io.FileReader;
    import java.io.IOException;
    
    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;
    import org.apache.lucene.util.Version;
    
    public class Indexer {
    	public static String indexDir = "h:/lucene"; // 创建索引目录
    	public static String dataDir = "h:/listFile";// 对指定目录中的（txt）文件进行索引
    	private IndexWriter writer;//索引类
    
    	/**
    	 * 初始化writer
    	 * 
    	 * @param indexDir
    	 *            索引存放目录
    	 * @throws IOException
    	 */
    	public Indexer(String indexDir) throws IOException {
    		Directory dir = FSDirectory.open(new File(indexDir));
    		IndexWriterConfig config = new IndexWriterConfig(Version.LUCENE_35,
    				new StandardAnalyzer(Version.LUCENE_35));
    		writer = new IndexWriter(dir, config);
    	}
    
    	/**
    	 * 关闭writer
    	 * 
    	 * @throws Exception
    	 */
    	public void close() throws Exception {
    		writer.close();
    	}
    
    	/**
    	 * 过滤文件（只索引txt文件）
    	 * 
    	 * @param dir
    	 *            要被索引的文件目录
    	 * @param filter
    	 *            过滤器
    	 * @return 返回被索引的文档数
    	 * @throws Exception
    	 */
    	public int index(String dir, FileFilter filter) throws Exception {
    		File[] files = new File(dir).listFiles();
    		for (File f : files) {
    			if (!f.isDirectory() && !f.isHidden() && f.exists() && f.canRead()
    					&& (filter == null || filter.accept(f))) {
    				indexFile(f);
    			}
    		}
    		return writer.numDocs();
    	}
    
    	/**
    	 * 添加索引文件
    	 * 
    	 * @param f
    	 *            符合条件的索引文件
    	 * @throws Exception
    	 */
    	private void indexFile(File f) throws Exception {
    		System.out.print("Indexing " + f.getCanonicalPath());
    		Document doc = getDocument(f);
    		writer.addDocument(doc);
    	}
    
    	/**
    	 * 向文档中添加索引字段
    	 * 
    	 * @param f
    	 *            索引文件
    	 * @return 文档doc
    	 * @throws Exception
    	 */
    	public Document getDocument(File f) throws Exception {
    		Document doc = new Document();
    		doc.add(new Field("contents", new FileReader(f)));
    		doc.add(new Field("filename", f.getName(), Field.Store.YES,
    				Field.Index.NOT_ANALYZED));
    		doc.add(new Field("fullpath", f.getCanonicalPath(), Field.Store.YES,
    				Field.Index.NOT_ANALYZED));
    		return doc;
    	}
    
    	public static void main(String[] args) {
    		long start = System.currentTimeMillis();
    		Indexer indexer = null;
    		int numIndexed = 0;
    		try {
    			indexer = new Indexer(indexDir);
    			numIndexed = indexer.index(dataDir, new TextFilesFilter());
    		} catch (IOException e) {
    			// TODO Auto-generated catch block
    			e.printStackTrace();
    		} catch (Exception e) {
    			// TODO Auto-generated catch block
    			e.printStackTrace();
    		}finally{
    			try {
    				//IndexerWriter写索引操作关闭，提交写索引（如没关闭会造成索引无法完整创建，查询时出错）
    				indexer.close();
    			} catch (Exception e) {
    				// TODO Auto-generated catch block
    				e.printStackTrace();
    			}
    		}
    		long end = System.currentTimeMillis();
    		System.out.println("\n Indexing " + numIndexed + " files took "
    				+ (end - start) + "milliseconds");
    
    	}
    
    	static class TextFilesFilter implements FileFilter {
    
    		@Override
    		public boolean accept(File pathname) {
    			return pathname.getName().toLowerCase().endsWith(".txt");
    		}
    
    	}
    }

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##     ##

## 搜索索引（Searcher） ##

package 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.IndexReader;
    import org.apache.lucene.index.Term;
    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.TermQuery;
    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 {
    	public static String indexDir = "h:/lucene";
    	public static void search(String indexDir, String q) throws IOException,
    			ParseException {
    		Directory dir = FSDirectory.open(new File(indexDir));
    		IndexReader reader = IndexReader.open(dir);
    		IndexSearcher searcher = new IndexSearcher(reader);
    //		QueryParser parser = new QueryParser(Version.LUCENE_35, "contents",
    //				new StandardAnalyzer(Version.LUCENE_35));
    //		Query query = parser.parse(q);
    		Query query = new TermQuery(new Term("contents",q));
    		long start = System.currentTimeMillis();
    		TopDocs hits = searcher.search(query, 10);
    		long end = System.currentTimeMillis();
    
    		System.err.println("Found " + hits.totalHits + " document(s) (in "
    				+ (end - start) + "milliseconds) that matched query'" + q
    				+ "':");
    
    		for (ScoreDoc scoreDoc : hits.scoreDocs) {
    			Document doc = searcher.doc(scoreDoc.doc);
    			System.out.println(doc.get("fullpath"));
    		}
    		searcher.close();
    	}
    
    	public static void main(String[] args) {
    		try {
    			search(indexDir, "apache");
    		} catch (IOException e) {
    			// TODO Auto-generated catch block
    			e.printStackTrace();
    		} catch (ParseException e) {
    			// TODO Auto-generated catch block
    			e.printStackTrace();
    		}
    	}
    }

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[Center]: /images/20220806/2fa41b9be27a4006b27f8f06a6718d29.png
[Center 1]: /images/20220806/18da2b2e3f5940f595b1f8ffdb3ea6c3.png