lucene3 学习日志

 

近来项目需要使用Lucene，工作之余上网学习了下相关内容，做个笔记
1.创建索引
  步骤：创建IndexWriter

IndexWriter writer = new IndexWriter(
				new NIOFSDirectory(new File(path)), new StandardAnalyzer(
						Version.LUCENE_30), MaxFieldLength.LIMITED);

        创建Document
        创建Field 包含 field名和field值
        将Field通过Document的add方法添加到Document中

Document doc = new Document();

		doc.add(new Field("text", "It is a text area", Store.YES,
				Index.ANALYZED_NO_NORMS));
		doc.add(new Field("info", "It is a Infomation  area", Store.YES,
				Index.ANALYZED_NO_NORMS));

        将Document通过IndexWriter的addDocument方法添加到IndexWriter中
        关闭IndexWriter

writer.addDocument(doc);writer.close();

2从索引中根据关键字查询
        创建IndexSearcher

IndexSearcher searcher = new IndexSearcher(new NIOFSDirectory(new File(
				path)));

        创建Query

Query query = new QueryParser(Version.LUCENE_30, field,
				new StandardAnalyzer(Version.LUCENE_30)).parse(keyword);

        通过IndexSearcher的search方法查找关键字，使用TopDocs封装结果集

TopDocs docs = searcher.search(query, 10);

全部代码：(包换了合并内存索引到硬盘索引中)

import java.io.File;

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.IndexReader;
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.NIOFSDirectory;
import org.apache.lucene.store.RAMDirectory;
import org.apache.lucene.util.Version;

public class TestLucen {

	public static final String path = "E:\\workspaces\\lucene\\index";

	public static void main(String[] args) throws Exception {
		writeIndex();
		readIndex("text", "area");
	}

	public static void writeIndex() throws Exception {
		// 硬盘索引
		IndexWriter writer = new IndexWriter(
				new NIOFSDirectory(new File(path)), new StandardAnalyzer(
						Version.LUCENE_30), MaxFieldLength.LIMITED);
		// Ram索引
		RAMDirectory ram = new RAMDirectory();
		IndexWriter ramwriter = new IndexWriter(ram, new StandardAnalyzer(
				Version.LUCENE_30), MaxFieldLength.LIMITED);
		Document doc = new Document();
		Document doc1 = new Document();

		doc.add(new Field("text", "It is a text area", Store.YES,
				Index.ANALYZED_NO_NORMS));
		doc.add(new Field("info", "It is a Infomation  area", Store.YES,
				Index.ANALYZED_NO_NORMS));
		writer.addDocument(doc);

		doc1.add(new Field("text", "it is another area", Store.YES,
				Index.ANALYZED));
		ramwriter.addDocument(doc1);
		ramwriter.optimize();
		ramwriter.close();
		// 将Ram索引合并到硬盘索引上，必须先调用ram的close方法
		writer.addIndexes(IndexReader.open(ram));
		writer.optimize();
		writer.close();
	}

	public static void readIndex(String field, String keyword) throws Exception {
		IndexSearcher searcher = new IndexSearcher(new NIOFSDirectory(new File(
				path)));
		Query query = new QueryParser(Version.LUCENE_30, field,
				new StandardAnalyzer(Version.LUCENE_30)).parse(keyword);
		TopDocs docs = searcher.search(query, 10);
		System.out.println("查找到" + docs.totalHits + "个\n对应的text为：");
		ScoreDoc[] doc = docs.scoreDocs;
		for (ScoreDoc d : doc) {
			Document docu = searcher.doc(d.doc);
			System.out.println(docu.get(field));
		}
	}
}

 执行结果：

 

查找到2个

对应的text为：

It is a text area

it is another area