搭建lucene的步骤这里就不详细介绍了,无外乎就是下载相关jar包,在eclipse中新建java工程,引入相关的jar包即可

本文主要在没有剖析lucene的源码之前实战一下,通过实战来促进研究

建立索引

下面的程序展示了indexer的使用

package com.wuyudong.mylucene;

import org.apache.lucene.index.IndexWriter;
import org.apache.lucene.analysis.standard.StandardAnalyzer;
import org.apache.lucene.document.Document;
import org.apache.lucene.document.Field;
import org.apache.lucene.store.FSDirectory;
import org.apache.lucene.store.Directory;
import org.apache.lucene.util.Version; import java.io.File;
import java.io.FileFilter;
import java.io.IOException;
import java.io.FileReader; public class IndexerTest { public static void main(String[] args) throws Exception {
if (args.length != 2) {
throw new IllegalArgumentException("Usage: java " + IndexerTest.class.getName()
+ " <index dir> <data dir>");
}
String indexDir = args[0]; //1 指定目录创建索引
String dataDir = args[1]; //2 对指定目录中的*.txt文件进行索引 long start = System.currentTimeMillis();
IndexerTest indexer = new IndexerTest(indexDir);
int numIndexed;
try {
numIndexed = indexer.index(dataDir, new TextFilesFilter());
} finally {
indexer.close();
}
long end = System.currentTimeMillis(); System.out.println("Indexing " + numIndexed + " files took "
+ (end - start) + " milliseconds");
} private IndexWriter writer; public IndexerTest(String indexDir) throws IOException {
Directory dir = FSDirectory.open(new File(indexDir));
writer = new IndexWriter(dir, //3 创建IndexWriter
new StandardAnalyzer( //
Version.LUCENE_30),//
true, //
IndexWriter.MaxFieldLength.UNLIMITED); //
} public void close() throws IOException {
writer.close(); //4 关闭IndexWriter
} public int index(String dataDir, FileFilter filter)
throws Exception { File[] files = new File(dataDir).listFiles(); for (File f: files) {
if (!f.isDirectory() &&
!f.isHidden() &&
f.exists() &&
f.canRead() &&
(filter == null || filter.accept(f))) {
indexFile(f);
}
} return writer.numDocs(); //5 返回被索引的文档数
} private static class TextFilesFilter implements FileFilter {
public boolean accept(File path) {
return path.getName().toLowerCase() //6 只索引*.txt文件,采用FileFilter
.endsWith(".txt"); //
}
} protected Document getDocument(File f) throws Exception {
Document doc = new Document();
doc.add(new Field("contents", new FileReader(f))); //7 索引文件内容
doc.add(new Field("filename", f.getName(), //8 索引文件名
Field.Store.YES, Field.Index.NOT_ANALYZED));//
doc.add(new Field("fullpath", f.getCanonicalPath(), //9 索引文件完整路径
Field.Store.YES, Field.Index.NOT_ANALYZED));//
return doc;
} private void indexFile(File f) throws Exception {
System.out.println("Indexing " + f.getCanonicalPath());
Document doc = getDocument(f);
writer.addDocument(doc); //10 向Lucene索引中添加文档
}
}

在eclipse中配置好参数:

E:\luceneinaction\index E:\luceneinaction\lia2e\src\lia\meetlucene\data

运行结果如下:

Indexing E:\luceneinaction\lia2e\src\lia\meetlucene\data\apache1.0.txt
Indexing E:\luceneinaction\lia2e\src\lia\meetlucene\data\apache1.1.txt
Indexing E:\luceneinaction\lia2e\src\lia\meetlucene\data\apache2.0.txt
Indexing E:\luceneinaction\lia2e\src\lia\meetlucene\data\cpl1.0.txt
Indexing E:\luceneinaction\lia2e\src\lia\meetlucene\data\epl1.0.txt
Indexing E:\luceneinaction\lia2e\src\lia\meetlucene\data\freebsd.txt
Indexing E:\luceneinaction\lia2e\src\lia\meetlucene\data\gpl1.0.txt
Indexing E:\luceneinaction\lia2e\src\lia\meetlucene\data\gpl2.0.txt
Indexing E:\luceneinaction\lia2e\src\lia\meetlucene\data\gpl3.0.txt
Indexing E:\luceneinaction\lia2e\src\lia\meetlucene\data\lgpl2.1.txt
Indexing E:\luceneinaction\lia2e\src\lia\meetlucene\data\lgpl3.txt
Indexing E:\luceneinaction\lia2e\src\lia\meetlucene\data\lpgl2.0.txt
Indexing E:\luceneinaction\lia2e\src\lia\meetlucene\data\mit.txt
Indexing E:\luceneinaction\lia2e\src\lia\meetlucene\data\mozilla1.1.txt
Indexing E:\luceneinaction\lia2e\src\lia\meetlucene\data\mozilla_eula_firefox3.txt
Indexing E:\luceneinaction\lia2e\src\lia\meetlucene\data\mozilla_eula_thunderbird2.txt
Indexing 16 files took 888 milliseconds

在index文件内会产生索引文件:

Lucene实战构建索引-LMLPHP

由于被索引的文件都很小,数量也不大(如下图),但是会花费888ms,还是很让人不安

Lucene实战构建索引-LMLPHP

总体说来,搜索索引比建立索引重要,因为搜索很多次,而索引只是建立一次

搜索索引

接下来将创建一个程序 来对上面创建的索引进行搜索:

import org.apache.lucene.document.Document;
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.FSDirectory;
import org.apache.lucene.store.Directory;
import org.apache.lucene.queryParser.QueryParser;
import org.apache.lucene.queryParser.ParseException;
import org.apache.lucene.analysis.standard.StandardAnalyzer;
import org.apache.lucene.util.Version; import java.io.File;
import java.io.IOException; public class SearcherTest { public static void main(String[] args) throws IllegalArgumentException,
IOException, ParseException {
if (args.length != 2) {
throw new IllegalArgumentException("Usage: java " + SearcherTest.class.getName()
+ " <index dir> <query>");
} String indexDir = args[0]; //1 解析输入的索引路径
String q = args[1]; //2 解析输入的查询字符串 search(indexDir, q);
} public static void search(String indexDir, String q)
throws IOException, ParseException { Directory dir = FSDirectory.open(new File(indexDir)); //3 打开索引文件
IndexSearcher is = new IndexSearcher(dir); //3 QueryParser parser = new QueryParser(Version.LUCENE_30, // 4 解析查询字符串
"contents", //
new StandardAnalyzer( //
Version.LUCENE_30)); //
Query query = parser.parse(q); //4
long start = System.currentTimeMillis();
TopDocs hits = is.search(query, 10); //5 搜索索引
long end = System.currentTimeMillis(); System.err.println("Found " + hits.totalHits + //6 记录索引状态
" document(s) (in " + (end - start) + //
" milliseconds) that matched query '" + //
q + "':"); // for(ScoreDoc scoreDoc : hits.scoreDocs) {
Document doc = is.doc(scoreDoc.doc); //7 返回匹配文本
System.out.println(doc.get("fullpath")); //8 显示匹配文件名
} is.close(); //9 关闭IndexSearcher
}
}

设置好参数:E:\luceneinaction\index patent

运行结果如下:

Found 8 document(s) (in 12 milliseconds) that matched query 'patent':
E:\luceneinaction\lia2e\src\lia\meetlucene\data\cpl1.0.txt
E:\luceneinaction\lia2e\src\lia\meetlucene\data\mozilla1.1.txt
E:\luceneinaction\lia2e\src\lia\meetlucene\data\epl1.0.txt
E:\luceneinaction\lia2e\src\lia\meetlucene\data\gpl3.0.txt
E:\luceneinaction\lia2e\src\lia\meetlucene\data\apache2.0.txt
E:\luceneinaction\lia2e\src\lia\meetlucene\data\gpl2.0.txt
E:\luceneinaction\lia2e\src\lia\meetlucene\data\lpgl2.0.txt
E:\luceneinaction\lia2e\src\lia\meetlucene\data\lgpl2.1.txt

可以看到速度很快(12ms),打印的是文件的绝对路径,这是因为indexer存储的是文件的绝对路径

05-11 10:49