导入Lucene.NET 开发包
Lucene 是apache软件基金会一个开放源代码的全文检索引擎工具包，是一个全文检索引擎的架构，提供了完整的查询引擎和索引引擎，部分文本分析引擎。Lucene的目的是为软件开发人员提供一个简单易用的工具包，以方便的在目标系统中实现全文检索的功能，或者是以此为基础建立起完整的全文检索引擎。Lucene.Net 是 .NET 版的Lucene。
你可以在这里下载到最新的Lucene.NET
创建索引、更新索引、删除索引
搜索，根据索引查找
IndexHelper 添加、更新、删除索引
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using System;using Lucene.Net.Store;using Lucene.Net.Index;using Lucene.Net.Analysis.PanGu;using Lucene.Net.Documents;namespace BLL{ class IndexHelper { /// <summary> /// 日志小助手 /// </summary> static Common.LogHelper logger = new Common.LogHelper(typeof(SearchBLL)); /// <summary> /// 索引保存的位置，保存在配置文件中从配置文件读取 /// </summary> static string indexPath = Common.ConfigurationHelper.AppSettingMapPath("IndexPath"); /// <summary> /// 创建索引文件或更新索引文件 /// </summary> /// <param name="item">索引信息</param> public static void CreateIndex(Model.HelperModel.IndexFileHelper item) { try { //索引存储库 FSDirectory directory = FSDirectory.Open(new System.IO.DirectoryInfo(indexPath), new NativeFSLockFactory()); //判断索引是否存在 bool isUpdate = IndexReader.IndexExists(directory); if (isUpdate) { //如果索引目录被锁定（比如索引过程中程序异常退出），则首先解锁 if (IndexWriter.IsLocked(directory)) { //解锁索引库 IndexWriter.Unlock(directory); } } //创建IndexWriter对象，添加索引 IndexWriter writer = new IndexWriter(directory, new PanGuAnalyzer(), !isUpdate, Lucene.Net.Index.IndexWriter.MaxFieldLength.UNLIMITED); //获取新闻 title部分 string title = item.FileTitle; //获取新闻主内容 string body = item.FileContent; //为避免重复索引，所以先删除number=i的记录，再重新添加 //尤其是更新的话，更是必须要先删除之前的索引 writer.DeleteDocuments(new Term("id", item.FileName)); //创建索引文件 Document Document document = new Document(); //只有对需要全文检索的字段才ANALYZED //添加id字段 document.Add(new Field("id", item.FileName, Field.Store.YES, Field.Index.NOT_ANALYZED)); //添加title字段 document.Add(new Field("title", title, Field.Store.YES, Field.Index.NOT_ANALYZED)); //添加body字段 document.Add(new Field("body", body, Field.Store.YES, Field.Index.ANALYZED, Lucene.Net.Documents.Field.TermVector.WITH_POSITIONS_OFFSETS)); //添加url字段 document.Add(new Field("url", item.FilePath, Field.Store.YES, Field.Index.NOT_ANALYZED)); //写入索引库 writer.AddDocument(document); //关闭资源 writer.Close(); //不要忘了Close，否则索引结果搜不到 directory.Close(); //记录日志 logger.Debug(String.Format("索引{0}创建成功",item.FileName)); } catch (SystemException ex) { //记录错误日志 logger.Error(ex); throw; } catch (Exception ex) { //记录错误日志 logger.Error(ex); throw; } } /// <summary> /// 根据id删除相应索引 /// </summary> /// <param name="guid">要删除的索引id</param> public static void DeleteIndex(string guid) { try { ////索引存储库 FSDirectory directory = FSDirectory.Open(new System.IO.DirectoryInfo(indexPath), new NativeFSLockFactory()); //判断索引库是否存在索引 bool isUpdate = IndexReader.IndexExists(directory); if (isUpdate) { //如果索引目录被锁定（比如索引过程中程序异常退出），则首先解锁 if (IndexWriter.IsLocked(directory)) { IndexWriter.Unlock(directory); } } IndexWriter writer = new IndexWriter(directory, new PanGuAnalyzer(), !isUpdate, Lucene.Net.Index.IndexWriter.MaxFieldLength.UNLIMITED); //删除索引文件 writer.DeleteDocuments(new Term("id", guid)); writer.Close(); directory.Close();//不要忘了Close，否则索引结果搜不到 logger.Debug(String.Format("删除索引{0}成功", guid)); } catch (Exception ex) { //记录日志 logger.Error(ex); //抛出异常 throw; } } }} |
Search 通过查找索引实现搜索
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using Lucene.Net.Analysis;using Lucene.Net.Analysis.PanGu;using Lucene.Net.Documents;using Lucene.Net.Index;using Lucene.Net.Search;using Lucene.Net.Store;using Model.HelperModel;using System;using System.Collections.Generic;namespace BLL{ public static class SearchBLL { //一个类中可能会有多处输出到日志，多处需要记录日志，常将logger做成static 静态变量 /// <summary> /// 日志助手 /// </summary> static Common.LogHelper logger = new Common.LogHelper(typeof(SearchBLL)); /// <summary> /// 索引保存位置 /// </summary> static string indexPath = Common.ConfigurationHelper.AppSettingMapPath("IndexPath"); /// <summary> /// 搜索 /// </summary> /// <param name="keywords">用户搜索的关键词</param> /// <returns>返回搜索的结果</returns> public static List<SearchResult> Search(string keywords) { try { //索引存储库 FSDirectory directory = FSDirectory.Open(new System.IO.DirectoryInfo(indexPath), new NoLockFactory()); //创建IndexReader对象 IndexReader reader = IndexReader.Open(directory, true); //创建IndexSearcher对象 IndexSearcher searcher = new IndexSearcher(reader); //新建PhraseQuery 查询对象 PhraseQuery query = new PhraseQuery(); //把用户输入的关键词进行拆词 foreach (string word in SplitWord(keywords)) { //添加搜索关键词 query.Add(new Term("body", word)); } //设置分词间距为100字之内 query.SetSlop(100); TopScoreDocCollector collector = TopScoreDocCollector.create(1000, true); //根据查询条件查询结果 searcher.Search(query, null, collector); //搜索到的ScoreDoc结果 ScoreDoc[] docs = collector.TopDocs(0, collector.GetTotalHits()).scoreDocs; //保存搜索结果的list List<SearchResult> listResult = new List<SearchResult>(); for (int i = 0; i < docs.Length; i++) { //取到文档的编号（主键，这个是Lucene .net分配的） //检索结果中只有文档的id，如果要取Document，则需要Doc再去取 //降低内容占用 int docId = docs[i].doc; //根据id找Document Document doc = searcher.Doc(docId); string number = doc.Get("id"); string title = doc.Get("title"); string body = doc.Get("body"); string url = doc.Get("url"); //建立一个搜索结果对象 SearchResult result = new SearchResult(); result.Number = number; result.Title = title; result.BodyPreview = Preview(body, keywords); result.Url = url; //添加到结果列表 listResult.Add(result); } if (listResult.Count == 0) { return null; } else { return listResult; } } catch (SystemException ex) { logger.Error(ex); return null; } catch (Exception ex) { logger.Error(ex); return null; } } /// <summary> /// 获取内容预览 /// </summary> /// <param name="body">内容</param> /// <param name="keyword">关键词</param> /// <returns></returns> private static string Preview(string body, string keyword) { //创建HTMLFormatter,参数为高亮单词的前后缀 PanGu.HighLight.SimpleHTMLFormatter simpleHTMLFormatter = new PanGu.HighLight.SimpleHTMLFormatter("<font color=\"red\">", "</font>"); //创建 Highlighter ，输入HTMLFormatter 和 盘古分词对象Semgent PanGu.HighLight.Highlighter highlighter = new PanGu.HighLight.Highlighter(simpleHTMLFormatter, new PanGu.Segment()); //设置每个摘要段的字符数 highlighter.FragmentSize = 100; //获取最匹配的摘要段 string bodyPreview = highlighter.GetBestFragment(keyword, body); return bodyPreview; } /// <summary> /// 盘古分词，对用户输入的搜索关键词进行分词 /// </summary> /// <param name="str">用户输入的关键词</param> /// <returns>分词之后的结果组成的数组</returns> private static string[] SplitWord(string str) { List<string> list = new List<string>(); Analyzer analyzer = new PanGuAnalyzer(); TokenStream tokenStream = analyzer.TokenStream("", new System.IO.StringReader(str)); Lucene.Net.Analysis.Token token = null; while ((token = tokenStream.Next()) != null) { list.Add(token.TermText()); } return list.ToArray(); } }} |
SearchResult 模型
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namespace Model.HelperModel{ public class SearchResult { public string Number { get; set; } public string Title { get; set; } public string BodyPreview { get; set; } public string Url { get; set; } }} |
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