導入Lucene.NET 開發(fā)包
Lucene 是apache軟件基金會一個開放源代碼的全文檢索引擎工具包，是一個全文檢索引擎的架構，提供了完整的查詢引擎和索引引擎，部分文本分析引擎。Lucene的目的是為軟件開發(fā)人員提供一個簡單易用的工具包，以方便的在目標系統(tǒng)中實現(xiàn)全文檢索的功能，或者是以此為基礎建立起完整的全文檢索引擎。Lucene.Net 是 .NET 版的Lucene。
你可以在這里下載到最新的Lucene.NET
創(chuàng)建索引、更新索引、刪除索引
搜索，根據(jù)索引查找
IndexHelper 添加、更新、刪除索引
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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，保存在配置文件中從配置文件讀取 /// </summary> static string indexPath = Common.ConfigurationHelper.AppSettingMapPath("IndexPath"); /// <summary> /// 創(chuàng)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 { //索引存儲庫 FSDirectory directory = FSDirectory.Open(new System.IO.DirectoryInfo(indexPath), new NativeFSLockFactory()); //判斷索引是否存在 bool isUpdate = IndexReader.IndexExists(directory); if (isUpdate) { //如果索引目錄被鎖定（比如索引過程中程序異常退出），則首先解鎖 if (IndexWriter.IsLocked(directory)) { //解鎖索引庫 IndexWriter.Unlock(directory); } } //創(chuàng)建IndexWriter對象，添加索引 IndexWriter writer = new IndexWriter(directory, new PanGuAnalyzer(), !isUpdate, Lucene.Net.Index.IndexWriter.MaxFieldLength.UNLIMITED); //獲取新聞 title部分 string title = item.FileTitle; //獲取新聞主內容 string body = item.FileContent; //為避免重復索引，所以先刪除number=i的記錄，再重新添加 //尤其是更新的話，更是必須要先刪除之前的索引 writer.DeleteDocuments(new Term("id", item.FileName)); //創(chuàng)建索引文件 Document Document document = new Document(); //只有對需要全文檢索的字段才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)); //寫入索引庫 writer.AddDocument(document); //關閉資源 writer.Close(); //不要忘了Close，否則索引結果搜不到 directory.Close(); //記錄日志 logger.Debug(String.Format("索引{0}創(chuàng)建成功",item.FileName)); } catch (SystemException ex) { //記錄錯誤日志 logger.Error(ex); throw; } catch (Exception ex) { //記錄錯誤日志 logger.Error(ex); throw; } } /// <summary> /// 根據(jù)id刪除相應索引 /// </summary> /// <param name="guid">要刪除的索引id</param> public static void DeleteIndex(string guid) { try { ////索引存儲庫 FSDirectory directory = FSDirectory.Open(new System.IO.DirectoryInfo(indexPath), new NativeFSLockFactory()); //判斷索引庫是否存在索引 bool isUpdate = IndexReader.IndexExists(directory); if (isUpdate) { //如果索引目錄被鎖定（比如索引過程中程序異常退出），則首先解鎖 if (IndexWriter.IsLocked(directory)) { IndexWriter.Unlock(directory); } } IndexWriter writer = new IndexWriter(directory, new PanGuAnalyzer(), !isUpdate, Lucene.Net.Index.IndexWriter.MaxFieldLength.UNLIMITED); //刪除索引文件 writer.DeleteDocuments(new Term("id", guid)); writer.Close(); directory.Close();//不要忘了Close，否則索引結果搜不到 logger.Debug(String.Format("刪除索引{0}成功", guid)); } catch (Exception ex) { //記錄日志 logger.Error(ex); //拋出異常 throw; } } }} |
Search 通過查找索引實現(xiàn)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 { //一個類中可能會有多處輸出到日志，多處需要記錄日志，常將logger做成static 靜態(tài)變量 /// <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">用戶搜索的關鍵詞</param> /// <returns>返回搜索的結果</returns> public static List<SearchResult> Search(string keywords) { try { //索引存儲庫 FSDirectory directory = FSDirectory.Open(new System.IO.DirectoryInfo(indexPath), new NoLockFactory()); //創(chuàng)建IndexReader對象 IndexReader reader = IndexReader.Open(directory, true); //創(chuàng)建IndexSearcher對象 IndexSearcher searcher = new IndexSearcher(reader); //新建PhraseQuery 查詢對象 PhraseQuery query = new PhraseQuery(); //把用戶輸入的關鍵詞進行拆詞 foreach (string word in SplitWord(keywords)) { //添加搜索關鍵詞 query.Add(new Term("body", word)); } //設置分詞間距為100字之內 query.SetSlop(100); TopScoreDocCollector collector = TopScoreDocCollector.create(1000, true); //根據(jù)查詢條件查詢結果 searcher.Search(query, null, collector); //搜索到的ScoreDoc結果 ScoreDoc[] docs = collector.TopDocs(0, collector.GetTotalHits()).scoreDocs; //保存搜索結果的list List<SearchResult> listResult = new List<SearchResult>(); for (int i = 0; i < docs.Length; i++) { //取到文檔的編號（主鍵，這個是Lucene .net分配的） //檢索結果中只有文檔的id，如果要取Document，則需要Doc再去取 //降低內容占用 int docId = docs[i].doc; //根據(jù)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"); //建立一個搜索結果對象 SearchResult result = new SearchResult(); result.Number = number; result.Title = title; result.BodyPreview = Preview(body, keywords); result.Url = url; //添加到結果列表 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> /// 獲取內容預覽 /// </summary> /// <param name="body">內容</param> /// <param name="keyword">關鍵詞</param> /// <returns></returns> private static string Preview(string body, string keyword) { //創(chuàng)建HTMLFormatter,參數(shù)為高亮單詞的前后綴 PanGu.HighLight.SimpleHTMLFormatter simpleHTMLFormatter = new PanGu.HighLight.SimpleHTMLFormatter("<font color=\"red\">", "</font>"); //創(chuàng)建 Highlighter ，輸入HTMLFormatter 和 盤古分詞對象Semgent PanGu.HighLight.Highlighter highlighter = new PanGu.HighLight.Highlighter(simpleHTMLFormatter, new PanGu.Segment()); //設置每個摘要段的字符數(shù) highlighter.FragmentSize = 100; //獲取最匹配的摘要段 string bodyPreview = highlighter.GetBestFragment(keyword, body); return bodyPreview; } /// <summary> /// 盤古分詞，對用戶輸入的搜索關鍵詞進行分詞 /// </summary> /// <param name="str">用戶輸入的關鍵詞</param> /// <returns>分詞之后的結果組成的數(shù)組</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; } }} |
以上所述就是本文的全部內容了，希望大家能夠喜歡。
