如何实现在结果中搜索 二次搜索实现
Lucene是可以做到的，利用lucene的Filter，具体可以查看lucene的api中的org.apache.lucene.search.CachingWrapperFilter，它可以缓存上次的搜索结果，从而实现在结果中的搜索。
测试实例：
package com.wsjava;
import?java.io.IOException;
import org.apache.lucene.analysis.SimpleAnalyzer;
import org.apache.lucene.document.Document;
import org.apache.lucene.document.Field;
import org.apache.lucene.index.IndexWriter;
import org.apache.lucene.queryParser.ParseException;
import org.apache.lucene.queryParser.QueryParser;
import org.apache.lucene.search.CachingWrapperFilter;
import org.apache.lucene.search.Filter;
import org.apache.lucene.search.Hits;
import org.apache.lucene.search.IndexSearcher;
import org.apache.lucene.search.Query;
import org.apache.lucene.search.QueryFilter;
public class IndexTest {
?????????
?????????public static void main(String[] args) throws IOException, ParseException {
?????????????????index();
?????????????????search("day"); //简单搜索
?????????????????searchInResult("day", "you"); //在结果集中搜索
?????????}
????????
?????????public static void index() throws IOException {
?????????????????IndexWriter writer = new IndexWriter("d:/tesindex",new SimpleAnalyzer(), true);
?????????????????writer.setMaxMergeDocs(1000);
?????????????????writer.setMergeFactor(100);
?????????????????for (int i = 0; i < 10; i++) {
?????????????????????????Document doc = new Document();
?????????????????????????String content = "How do you do?";
?????????????????????????if (i >= 5) {
?????????????????????????????????content = "What's a good day. ";
?????????????????????????}
?????????????????????????if (i >= 7) {
?????????????????????????????????content = "Nice day. Thanks you!";
?????????????????????????}
?????????????????????????doc.add(new Field("content", content, Field.Store.YES,Field.Index.TOKENIZED));
?????????????????????????writer.addDocument(doc);
?????????????????}
?????????}
????????
?????????//简单实现对qw的搜索.
?????????public static void?search(String qw) throws IOException, ParseException {
?????????????????QueryParser queryParser = new QueryParser("content",new SimpleAnalyzer());
?????????????????Query query = queryParser.parse(qw.trim());
?????????????????QueryFilter filter = new QueryFilter(query);
???????????????
?????????????????search(query, filter);
?????????}
????????
?????????//在搜索oldqw的结果集中搜索qw.
?????????public static void searchInResult(String qw, String oldqw) throws ParseException, IOException {???????????????
????????????????QueryParser queryParser = new QueryParser("content",new SimpleAnalyzer());
?????????????????Query query = queryParser.parse(qw.trim());
?????????????????Query oldQuery = queryParser.parse(oldqw.trim());
?????????????????QueryFilter oldFilter = new QueryFilter(oldQuery);
?????????????????CachingWrapperFilter filter = new CachingWrapperFilter(oldFilter);
???????????????
?????????????????search(query, filter);
?????????}
????????
?????????private static void search(Query query, Filter filter) throws IOException, ParseException {
?????????????????IndexSearcher ins = new IndexSearcher("d:/tesindex");
????????????????Hits hits = ins.search(query, filter);
?????????????????for (int i = 0; i < hits.length(); i++) {
?????????????????????????Document doc = hits.doc(i);
?????????????????????????System.out.println(doc.get("content"));
?????????????????}
?????????????????System.out.println();
?????????}
}
Lucene.net的搜索结果的百分比相关度值是如何实现的？
答：
????Hits result = searcher.Search(q);
????float score = result.Score(n) ;//n为查询结果文挡序号，返回的是一个<=1f的float的值，表示为百分比字符串：score.ToString("0%") ;
问：如何通过编程的方式改变Lucene.net的锁文件存放的位置？
答：
????Lucene.net的锁文件默认是存放系统临时文件夹,可以通过下面的语句来修改
????System.Configuration.ConfigurationSettings.AppSettings.Add("Lucene.Net.lockDir", "your new lockDir") ;
????通过FSDirectory.LOCK_DIR可以获得锁文件存放的位置(文件夹)
???
问：如何判断某个索引库被锁定,如何强制解除锁定？
答：
???具体实现，可以参看Lucene.Net.Store.FSDirectory的Obtain()(判断是否锁定)方法和Release()方法(解除锁定)??
???备注：还有一个IsLocked方法也可以参考下。
??
问：如何实现多个索引的联合搜索？
答：
???IndexSearcher[] searchers = new IndexSearcher[2];
???searchers[0] = new IndexSearcher(dir1) ;
???searchers[1] = new IndexSearcher(dir2) ;
??
???MultiSearcher searcher = new MultiSearcher(searchers) ;//或ParallelMultiSearcher searcher = new ParallelMultiSearcher(searchers) ;
???searcher.Search(query) ;
??
???ParallelMultiSearcher与MultiSearcher的区别，前者为每一个索引单独开一个线程,以多线程的方式同步搜索；后者是逐个依次搜索，然后合并；
???所以ParallelMultiSearcher的搜索总用时是最慢的哪个索引的搜索用时，MultiSearcher则是搜索总用时等于所有索引搜索用时之和；
??
问：如何实现在结果中搜索？
答：
????*方法一，使用CachingWrapperFilter。不能实现无限级的“在结果中搜索”:
????QueryParser parser = new QueryParser("content", analyzer);
???
????Query currentQuery = parser.Parse(currentKeyword) ;
?Query oldQuery = parser.Parse(oldKeyword) ;
?QueryFilter oldFilter = new QueryFilter(oldQuery) ;
?CachingWrapperFilter filter = new CachingWrapperFilter(oldFilter) ;
?
?IndexSearcher searcher = new IndexSearcher(indexDir);
?
?Hits result = searcher.Search(currentQuery, filter) ;
?
?*方法二，将多个查询关键词做AND的BooleanQuery或者直接构造查询Sytax传给QueryParser，都可以实现无限级的“在结果中搜索“。
?
问：BooleanQuery.maxClauseCount的含义？
答：
????添加到BooleanQuery的最多的Query数，默认是1024。超过该值会抛出TooManyClauses异常，可以通过BooleanQuery.SetMaxClauseCount(int)设置新的值。
????备注：含义解释未明确。
问：如何判断一个索引库是否存在？
答：
???string indexPath = "your indexPath" ; //索引所在目录
???if (System.IO.Directory.Exists(indexPath) && System.IO.File.Exists(Path.Combine(indexPath,"segments")
??????//存在
???else
??????//不存在
??
???当然有更直接的方法
???if (Lucene.Net.Index.IndexReader.IndexExists(indexPath))
?????//存在
???else
?????//不存在
????
???Lucene.Net.Index.IndexReader.IndexExists方法内部的实现方式和上面的类似，当然直接用Lucene.Net.Index.IndexReader.IndexExists更可靠些。
?
????Lucene.Net.Store.Directory directory1 = FSDirectory.GetDirectory("e:\\Index1", false);
????Lucene.Net.Store.Directory directory2 = FSDirectory.GetDirectory("e:\\Index2", false);
????IndexWriter writer = new IndexWriter(directory1, new ChineseAnalyzer(), false);
????writer.AddIndexes(new Lucene.Net.Store.Directory[] { directory2 });
????Console.WriteLine("正在合并索引"+writer.DocCount().ToString());
????writer.Close();
