lucene排序、设置权重、优化、分布式搜索

1、1. 基本应用 using System;using System.Collect ion s.Ge neric;using System.Text;using Luce ne.Net;using Luce ne.Net.A nalysis;using Luce ne.Net.A nalysis.Sta ndard;using Luce ne.Net.Docume nts;using Luce ne.Net.l ndex;using Luce ne.Net.QueryParsers;using Luce ne.Net.Search;using Luce ne.Net.Store;using L

2、uce ne.Net.Util;n amespace Con soleApplicati on 1.Luce nepublic class Luce neTestprivate const stri ng FieldName =a?name ;private const string FieldValue =value ;private Directory directory = new RAMDirectory();private An alyzer an alyzer = new Stan dardA nalyzer();public Luce neTest()private void I

3、n dex()In dexWriter writer = new In dexWriter(directory, an alyzer, true);writer.maxFieldLe ngth = 1000;for (int i = 1; i <= 100; i+)Docume nt docume nt = new Docume nt();document.Add(new Field(FieldName,name ” + i, Field.Store.YES,Field.I ndex.UN_TOKENIZED);docume nt.Add( new Field(FieldValue,He

4、llo, World! ”，Field.Store.YES,Field .In dex.TOKENIZED);writer.AddDocume nt(docume nt);writer.Optimize();writer.Close();private void Search()Query query = QueryParser.Parse( name* ”，FieldName, analyzer);In dexSearcher searcher = new In dexSearcher(directory);Hits hits = searcher.Search(query);Console

5、.WriteLine(符合条件记录：0;索引库记录总数：1 ”, hits.Length(),searcher.Reader.NumDocs();for (int i = 0; i < hits.Le ngth(); i+)int docId = hits .I d(i);string name = hits.Doc(i).Get(FieldName);stri ng value = hits.Doc(i).Get(FieldValue);float score = hits.Score(i);Co nsole.WriteL in e(0: DocId:1; Name:2; Value:

6、3; Score:4 ”，i + 1, docId, n ame, value, score);searcher.Close();除了 RAMDirectory ,还可以使用 FSDirectory。(注意 FSDirectory .GetDirectory 的 create 参数，为true时将删除已有索引库文件， 可以通过IndexReader.IndexExists() 方法判断。) 从指定目录打开已有索引库。private Directory directory = FSDirectory.GetDirectory(c：index ”，false);将索引库载入内存，以提高搜索速度。p

7、rivate Directory directory = new RAMDirectory(FSDirectory.GetDirectory("c:index ”，false);/或/private Directory directory = new RAMDirectory(c:in dex");2. 多字段搜索使用MultiFieldQueryParser可以指定多个搜索字段。Query query = MultiFieldQueryParser.Parse( name* ”new string FieldName,FieldValue , an alyzer);In

8、dexReader reader = In dexReader.Ope n( directory);In dexSearcher searcher = new In dexSearcher(reader);Hits hits = searcher.Search(query);3. 多条件搜索除了使用QueryParser.Parse分解复杂的搜索语法外，还可以通过组合多个Query来达到目的。hame1 "); /词语搜索name*"); / 通配符name1 "); /字段搜索Query query1 = new TermQuery (new Term(Fiel

9、dValue,Query query2 = new WildcardQuery (new Term(FieldName,/Query query3 = new PrefixQuery (new Term(FieldName, Field:Keyword，自动在结尾添加* /Query query4 = new Ran geQuery (new Term(FieldNumber,NumberTools.LongT oString(1 1L), new Term(FieldNumber,NumberTools.LongT oString(13L), true); / 范围搜索/Query quer

10、y5 = new FilteredQuery(query, filter); /带过滤条件的搜索Boolea nQuery query = new Boolea nQuery();query.Add(query1, Boolea nClause.Occur.MUST);query.Add(query2, Boolea nClause.Occur.MUST);In dexSearcher searcher = new In dexSearcher(reader);Hits hits = searcher.Search(query);4. 设置权重可以给Document和Field增加权重(Boo

11、st)，使其在搜索结果排名更加靠前。缺省情况下，搜索结果以Document.Score作为排序依据，该数值越大排名越靠前。Boost缺省值为1。Score = Score * Boost通过上面的公式，我们就可以设置不同的权重来影响排名。如下面的例子中根据VIP级别设定不同的权重。Docume nt docume nt = new Docume nt();switch (vip)case VIP .Gold: document.SetBoost(2F); break;case VIP .Argentine: document.SetBoost(1.5F); break;只要Boost足够大，那

12、么就可以让某个命中结果永远排第一位，这就是百度等网站的”收费排名”业务。明显有失公平，鄙视一把。5. 排序通过SortField的构造参数，我们可以设置排序字段，排序条件，以及倒排。Sort sort = new Sort( new SortField(FieldName, SortField.DOC, false);In dexSearcher searcher = new In dexSearcher(reader);Hits hits = searcher.Search(query, sort);排序对搜索速度影响还是很大的，尽可能不要使用多个排序条件。6. 过滤使用Filter对搜索结

13、果进行过滤，可以获得更小范围内更精确的结果。举个例子，我们搜索上架时间在2005-10-1至U 2005-10-30 之间的商品。对于日期时间，我们需要转换一下才能添加到索引库，同时还必须是索引字段。/indexdocument.Add(FieldDate, DateField.DateToString(date), Field.Store.YES,Field.I ndex.UN_TOKENIZED);/ searchFilter filter = new DateFilter(FieldDate, DateTime.Parse(2005-10-1 ”)，DateTime.Parse( 200

14、5-10-30 )；Hits hits = searcher.Search(query, filter);除了日期时间，还可以使用整数。比如搜索价格在100 200 之间的商品。Luce ne.Net NumberTools对于数字进行了补位处理，如果需要使用浮点数可以自己参考源码进行。/indexdocument.Add(new Field(FieldNumber, NumberTools.LongToString(long)price), Field.Store.YES, Fieldn dex.UN_TOKENIZED);/ searchFilter filter = new Ra nge

15、Filter(FieldNumber, NumberTools.Lo ngToStri ng(100L),NumberTools.LongT oString(200L), true, true);Hits hits = searcher.Search(query, filter);使用Query作为过滤条件。QueryFilter filter = new QueryFilter(QueryParser.Parse(name2 ",FieldValue, analyzer);我们还可以使用FilteredQuery进行多条件过滤。Filter filter = new DateFil

16、ter(FieldDate, DateTime.Parse(2005-10-10 ”)，DateTime.Parse( 2005-10-15 )；Filter filter2 = new Ran geFilter(FieldNumber, NumberTools.L on gToStri ng(11L),NumberTools.LongT oString(13L), true, true);Query query = QueryParser.Parse(name* ”，FieldName, analyzer);query = new FilteredQuery(query, filter);q

17、uery = new FilteredQuery(query, filter2);In dexSearcher searcher = new In dexSearcher(reader);Hits hits = searcher.Search(query);7. 分布搜索我们可以使用 MultiReader 或MultiSearcher 搜索多个索引库。MultiReader reader = new MultiReader( new In dexReader IndexReader.Open("c:index "),1 ndexReader.Open("serv

18、erindex ");In dexSearcher searcher = new In dexSearcher(reader);Hits hits = searcher.Search(query);或In dexSearcher searcher1 = new In dexSearcher(reader1);In dexSearcher searcher2 = new In dexSearcher(reader2);MultiSearcher searcher = new MultiSearcher( new Searchable searcher1, searcher2 );Hit

19、s hits = searcher.Search(query);还可以使用 ParallelMultiSearcher进行多线程并行搜索。8. 合并索引库将 directory1 合并到 directory2 中。Directory directory1 = FSDirectory.GetDirectory(ihdex1 ",false);Directory directory2 = FSDirectory.GetDirectory(ihdex2 ",false);IndexWriter writer = new IndexWriter(directory2, analyz

20、er, false);writer.Add In dexes (new Directory directory );Co nsole.WriteL in e(writer.DocCou nt();writer.Close();9. 显示搜索语法字符串我们组合了很多种搜索条件，或许想看看与其对等的搜索语法串是什么样的。Boolea nQuery query = new Boolea nQuery();query.Add(query1, true, false);query.Add(query2, true, false);/Console.WriteLine(Syntax: 0 ”，query.ToString();输出：Sy ntax: +(name:n ame* value: name*) +nu mber:0000000000000000b TO0000000000000000d呵呵，就这么简单。10. 操作索引库删除(软删除，仅添加了删除标记。调用IndexWriter.Optimize()后真正删除。)In dexReader reader = In dexReader.Ope n( directory);/删除指定序号(DocId)的 Document 。reader.Delete(123);II删除包含指定 Te