完整版见 https://jadyer.github.io/2013/08/18/lucene-index/

package com.jadyer.lucene;

import java.io.File;
import java.io.IOException;
import java.text.SimpleDateFormat;
import java.util.Date;

import org.apache.lucene.analysis.standard.StandardAnalyzer;
import org.apache.lucene.document.Document;
import org.apache.lucene.document.Field;
import org.apache.lucene.document.NumericField;
import org.apache.lucene.index.IndexReader;
import org.apache.lucene.index.IndexWriter;
import org.apache.lucene.index.IndexWriterConfig;
import org.apache.lucene.index.Term;
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;

/**
 * 【Lucene3.6.2入门系列】第02节_针对索引文件的CRUD
 * @see =============================================================================================================
 * @see Lucene官网:http://lucene.apache.org
 * @see Lucene下载:http://archive.apache.org/dist/lucene/java/
 * @see Lucene文档:http://wiki.apache.org/lucene-java/
 * @see =============================================================================================================
 * @see 使用Luke查看分词信息(http://code.google.com/p/luke/)
 * @see 1)引言:每一个Lucene版本都会有一个相应的Luke文件
 * @see 2)打开:双击或java -jar lukeall-3.5.0.jar
 * @see 3)选择索引的存放目录后点击OK即可
 * @see 7)如果我们的索引有改变,可以点击右侧的Re-open按钮重新载入索引
 * @see 4)Luke界面右下角的Top ranking terms窗口中显示的就是分词信息。其中Rank列表示出现频率
 * @see 5)Luke菜单下的Documents选项卡中显示的就是文档信息,我们可以根据文档序号来浏览(点击向左和向右的方向箭头)
 * @see 6)Luke菜单下的Search选项卡中可以根据我们输入的表达式来查文档内容
 * @see   比如在Enter search expression here:输入content:my,再在右侧点击一个黑色粗体字的Search大按钮即可
 * @see =============================================================================================================
 * @create Jun 30, 2012 4:34:09 PM
 * @author 玄玉<http://blog.csdn.net/jadyer>
 */
public class HelloIndex {
	/*
	 * 定义一组数据,用来演示搜索(这里有一封邮件为例)
	 * 假设每一个变量代表一个Document,这里就定义了6个Document
	 */
	//邮件编号
	private String[] ids = {"1", "2", "3", "4", "5", "6"};
	//邮件主题
	private String[] names = {"Michael", "Scofield", "Tbag", "Jack", "Jade", "Jadyer"};
	//邮件地址
	private String[] emails = {"aa@jadyer.us", "bb@jadyer.cn", "cc@jadyer.cc", "dd@jadyer.tw", "ee@jadyer.hk", "ff@jadyer.me"};
	//邮件内容
	private String[] contents = {"my blog", "my website", "my name", "I am JavaDeveloper", "I am from Haerbin", "I like Lucene"};
	//邮件附件(为数字和日期加索引,与,字符串加索引的方式不同)
	private int[] attachs = {9,3,5,4,1,2};
	//邮件日期
	private Date[] dates = new Date[ids.length];
	//它的创建是比较耗时耗资源的,所以这里只让它创建一次,此时reader处于整个生命周期中,实际应用中也可能直接放到ApplicationContext里面
	private static IndexReader reader = null;
	private Directory directory = null;

	public HelloIndex(){
		SimpleDateFormat sdf = new SimpleDateFormat("yyyyMMdd");
		try {
			dates[0] = sdf.parse("20120601");
			dates[1] = sdf.parse("20120603");
			dates[2] = sdf.parse("20120605");
			dates[3] = sdf.parse("20120607");
			dates[4] = sdf.parse("20120609");
			dates[5] = sdf.parse("20120611");
			directory = FSDirectory.open(new File("myExample/02_index/"));
		} catch (Exception e) {
			e.printStackTrace();
		}
	}
	
	
	/**
	 * 获取IndexReader实例
	 */
	private IndexReader getIndexReader(){
		try {
			if(reader == null){
				reader = IndexReader.open(directory);
			}else{
				//if the index was changed since the provided reader was opened, open and return a new reader; else,return null
				//如果当前reader在打开期间index发生改变,则打开并返回一个新的IndexReader,否则返回null
				IndexReader ir = IndexReader.openIfChanged(reader);
				if(ir != null){
					reader.close(); //关闭原reader
					reader = ir;    //赋予新reader
				}
			}
			return reader;
		}catch(Exception e) {
			e.printStackTrace();
		}
		return null; //发生异常则返回null
	}
	
	
	/**
	 * 通过IndexReader获取文档数量
	 */
	public void getDocsCount(){
		System.out.println("maxDocs:" + this.getIndexReader().maxDoc());
		System.out.println("numDocs:" + this.getIndexReader().numDocs());
		System.out.println("deletedDocs:" + this.getIndexReader().numDeletedDocs());
	}
	
	
	/**
	 * 创建索引
	 */
	public void createIndex(){
		IndexWriter writer = null;
		Document doc = null;
		try{
			writer = new IndexWriter(directory, new IndexWriterConfig(Version.LUCENE_36, new StandardAnalyzer(Version.LUCENE_36)));
			writer.deleteAll();              //创建索引之前,先把文档清空掉
			for(int i=0; i<ids.length; i++){ //遍历ID来创建文档
				doc = new Document();
				doc.add(new Field("id", ids[i], Field.Store.YES, Field.Index.NOT_ANALYZED_NO_NORMS));
				doc.add(new Field("name", names[i], Field.Store.YES, Field.Index.NOT_ANALYZED_NO_NORMS));
				doc.add(new Field("email", emails[i], Field.Store.YES, Field.Index.NOT_ANALYZED));
				doc.add(new Field("content", contents[i], Field.Store.NO, Field.Index.ANALYZED));
				doc.add(new NumericField("attach", Field.Store.YES, true).setIntValue(attachs[i]));        //为数字加索引(第三个参数指定是否索引)
				doc.add(new NumericField("date", Field.Store.YES, true).setLongValue(dates[i].getTime())); //为日期加索引
				/*
				 * 建立索引时加权
				 * 定义排名规则,即加权,这里是为指定邮件名结尾的emails加权
				 */
				if(emails[i].endsWith("jadyer.cn")){
					doc.setBoost(2.0f);
				}else if(emails[i].endsWith("jadyer.me")){
					doc.setBoost(1.5f); //为文档加权....默认为1.0,权值越高则排名越高,显示得就越靠前
				}else{
					doc.setBoost(0.5f); //注意它的参数类型是Float
				}
				writer.addDocument(doc);
			}
		}catch(Exception e) {
			e.printStackTrace();
		}finally{
			if(null != writer){
				try {
					writer.close();
				} catch (IOException ce) {
					ce.printStackTrace();
				}
			}
		}
	}
	
	
	/**
	 * 搜索文件
	 */
	public void searchFile(){
		IndexSearcher searcher = new IndexSearcher(this.getIndexReader());
		Query query = new TermQuery(new Term("content", "my")); //精确搜索:搜索"content"中包含"my"的文档
		try{
			TopDocs tds = searcher.search(query, 10);
			for(ScoreDoc sd : tds.scoreDocs){
				Document doc = searcher.doc(sd.doc); //sd.doc得到的是文档的序号
				//doc.getBoost()得到的权值与创建索引时设置的权值之间是不相搭的,创建索引时的权值的查看需要使用Luke工具
				//              之所以这样,是因为这里的Document对象(是获取到的)与创建索引时的Document对象,不是同一个对象
				//sd.score得到的是该文档的评分,该评分规则的公式是比较复杂的,它主要与文档的权值和出现次数成正比
				System.out.print("(" + sd.doc + "|" + doc.getBoost() + "|" + sd.score + ")" + doc.get("name") + "[" + doc.get("email") + "]-->");
				System.out.println(doc.get("id") + "," + doc.get("attach") + "," + new SimpleDateFormat("yyyyMMdd").format(new Date(Long.parseLong(doc.get("date")))));
			}
		}catch(Exception e){
			e.printStackTrace();
		}finally{
			if(null != searcher){
				try {
					searcher.close();
				} catch (IOException e) {
					e.printStackTrace();
				}
			}
		}
	}
	
	
	/**
	 * 更新索引
	 * @see Lucene其实并未提供更新索引的方法,这里的更新操作内部是先删除再添加的方式
	 * @see 因为Lucene认为更新索引的代价,与删除后重建索引的代价,二者是差不多的
	 */
	public void updateIndex(){
		IndexWriter writer = null;
		Document doc = new Document();
		try{
			writer = new IndexWriter(directory, new IndexWriterConfig(Version.LUCENE_36, new StandardAnalyzer(Version.LUCENE_36)));
			doc.add(new Field("id", "1111", Field.Store.YES, Field.Index.NOT_ANALYZED_NO_NORMS));
			doc.add(new Field("name", names[0], Field.Store.YES, Field.Index.NOT_ANALYZED_NO_NORMS));
			doc.add(new Field("email", emails[0], Field.Store.YES, Field.Index.NOT_ANALYZED));
			doc.add(new Field("content", contents[0], Field.Store.NO, Field.Index.ANALYZED));
			doc.add(new NumericField("attach", Field.Store.YES, true).setIntValue(attachs[0]));
			doc.add(new NumericField("date", Field.Store.YES, true).setLongValue(dates[0].getTime()));
			//其实它会先删除索引文档中id为1的文档,然后再将这里的doc对象重新索引,所以即便这里的1!=1111,但它并不会报错
			//所以在执行完该方法后:maxDocs=7,numDocs=6,deletedDocs=1,就是因为Lucene会先删除再添加
			writer.updateDocument(new Term("id","1"), doc);
		}catch(Exception e) {
			e.printStackTrace();
		}finally{
			if(null != writer){
				try {
					writer.close();
				} catch (IOException ce) {
					ce.printStackTrace();
				}
			}
		}
	}
	
	
	/**
	 * 删除索引
	 * @see -----------------------------------------------------------------------------------------------------
	 * @see 在执行完该方法后,再执行本类的searchFile()方法,得知numDocs=5,maxDocs=6,deletedDocs=1
	 * @see 这说明此时删除的文档并没有被完全删除,而是存储在一个回收站中,它是可以恢复的
	 * @see -----------------------------------------------------------------------------------------------------
	 * @see 从回收站中清空索引IndexWriter
	 * @see 对于清空索引,Lucene3.5之前叫做优化,调用的是IndexWriter.optimize()方法,但该方法已被禁用
	 * @see 因为optimize时它会全部更新索引,这一过程所涉及到的负载是很大的,于是弃用了该方法,使用forceMerge代替
	 * @see 使用IndexWriter.forceMergeDeletes()方法可以强制清空回收站中的内容
	 * @see 另外IndexWriter.forceMerge(3)方法会将索引合并为3段,这3段中的被删除的数据也会被清空
	 * @see 但其在Lucene3.5之后不建议使用,因为其会消耗大量的开销,而Lucene会根据情况自动处理的
	 * @see -----------------------------------------------------------------------------------------------------
	 */
	public void deleteIndex(){
		IndexWriter writer = null;
		try{
			writer = new IndexWriter(directory, new IndexWriterConfig(Version.LUCENE_36, new StandardAnalyzer(Version.LUCENE_36)));
			//其参数可以传Query或Term....Query指的是可以查询出一系列的结果并将其全部删掉,而Term属于精确查找
			writer.deleteDocuments(new Term("id", "1")); //删除索引文档中id为1的文档
		}catch(Exception e) {
			e.printStackTrace();
		}finally{
			if(null != writer){
				try {
					writer.close();
				} catch (IOException ce) {
					ce.printStackTrace();
				}
			}
		}
	}
	
	
	/**
	 * 恢复索引
	 * @see 建议弃用
	 */
	@Deprecated
	public void unDeleteIndex(){
		IndexReader reader = null;
		try {
			//IndexReader.open(directory)此时该IndexReader默认的readOnly=true,而在恢复索引时应该指定其为非只读的
			reader = IndexReader.open(directory, false);
			//Deprecated. Write support will be removed in Lucene 4.0. There will be no replacement for this method.
			reader.undeleteAll();
		} catch (Exception e) {
			e.printStackTrace();
		}finally{
			if(null != reader){
				try {
					reader.close();
				} catch (IOException e) {
					e.printStackTrace();
				}
			}
		}
	}
}

下面是用JUnit4.x写的一个小测试

package com.jadyer.test;

import org.junit.After;
import org.junit.Before;
import org.junit.Test;

import com.jadyer.lucene.HelloIndex;

public class HelloIndexTest {
	private HelloIndex hello;
	
	@Before
	public void init(){
		hello = new HelloIndex();
	}
	
	@After
	public void destroy(){
		hello.getDocsCount();
	}
	
	
	@Test
	public void createIndex(){
		hello.createIndex();
	}
	
	
	@Test
	public void searchFile(){
		hello.searchFile();
	}
	
	
	@Test
	public void updateIndex(){
		hello.updateIndex();
	}
	
	
	@Test
	public void deleteIndex(){
		hello.deleteIndex();
	}
	
	
	@Test
	@SuppressWarnings("deprecation")
	public void unDeleteIndex(){
		hello.unDeleteIndex();
	}
}