最近由于工作原因，一直忙于公司的各种项目（大部份都是基于spring cloud的微服务项目），故有一段时间没有与大家分享总结最近的技术研究成果的，其实最近我一直在不断的深入研究学习Spring、Spring Boot、Spring Cloud的各种框架原理，同时也随时关注着.NET CORE的发展情况及最新技术点，也在极客时间上订阅相关的专栏，只要下班有空我都会去认真阅读观看，纸质书箱也买了一些，总之近一年都是在通过：微信技术公众号（.NET、JAVA、算法、前端等技术方向）、极客时间、技术书箱 不断的吸取、借鉴他人之精华，从而不断的充实提高自己的技术水平，所谓：学如逆水行舟，不进则退，工作中学习，学习后工作中运用，当然写文章分享是一种总结，同时也是“温故而知新”的最佳应用。
前面废话说得有点多了，就直奔本文的主题内容，编写一个基于Lucene.Net的搜索引擎查询通用工具类：SearchEngineUtil，Lucene是什么，见百度百科 ,重点是:Lucene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，Lucene.NET是C#及.NET运行时下的另一种语言的实现，官网地址： ，具体用法就不多说了，官网以及网上都有很多，但由于Lucene.Net的原生SDK中的API比较复杂，用起来不太方便，故我进行了适当的封装，把常用的增、删、改、查（分页查）在保证灵活度的情况下进行了封装，使得操作Lucene.Net变得相对简单一些，代码本身也不复杂，贴出完整的SearchEngineUtil代码如下：
using Lucene.Net.Analysis.PanGu; using Lucene.Net.Documents; using Lucene.Net.Index; using Lucene.Net.QueryParsers; using Lucene.Net.Search; using Lucene.Net.Store; using NLog; using PanGu; using PanGu.HighLight; using System; using System.Collections.Generic; using System.IO; using System.Linq; using System.Reflection; using System.Text; namespace CN.Zuowenjun.Blog.Common { /// <summary> /// Lucene 搜索引擎实用工具类 /// Author:zuowenjun /// </summary> public class SearchEngineUtil { /// <summary> /// 创建并添加索引记录 /// </summary> /// <typeparam></typeparam> /// <param></param> /// <param></param> /// <param></param> public static void AddIndex<TIndex>(string indexDir, TIndex indexData, Action<Document, TIndex> setDocFiledsAction) { //创建索引目录 if (!System.IO.Directory.Exists(indexDir)) { System.IO.Directory.CreateDirectory(indexDir); } FSDirectory directory = FSDirectory.Open(new DirectoryInfo(indexDir), new NativeFSLockFactory()); 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); } } using (IndexWriter writer = new IndexWriter(directory, new PanGuAnalyzer(), !isUpdate, IndexWriter.MaxFieldLength.UNLIMITED)) { Document document = new Document(); setDocFiledsAction(document, indexData); writer.AddDocument(document); writer.Optimize();//优化索引 } } /// <summary> /// 删除索引记录 /// </summary> /// <param></param> /// <param></param> /// <param></param> public static void DeleteIndex(string indexDir, string keyFiledName, object keyFileValue) { FSDirectory directory = FSDirectory.Open(new DirectoryInfo(indexDir), new NativeFSLockFactory()); if (!IndexReader.IndexExists(directory)) { return; } using (IndexWriter iw = new IndexWriter(directory, new PanGuAnalyzer(), IndexWriter.MaxFieldLength.UNLIMITED)) { iw.DeleteDocuments(new Term(keyFiledName, keyFileValue.ToString())); iw.Optimize();//删除文件后并非从磁盘中移除，而是生成一个.del的文件，需要调用Optimize方法来清除。在清除文件前可以使用UndeleteAll方法恢复 } } /// <summary> /// 更新索引记录 /// </summary> /// <param></param> /// <param></param> /// <param></param> /// <param></param> public static void UpdateIndex(string indexDir, string keyFiledName, object keyFileValue, Document doc) { FSDirectory directory = FSDirectory.Open(new DirectoryInfo(indexDir), new NativeFSLockFactory()); if (!IndexReader.IndexExists(directory)) { return; } using (IndexWriter iw = new IndexWriter(directory, new PanGuAnalyzer(), IndexWriter.MaxFieldLength.UNLIMITED)) { iw.UpdateDocument(new Term(keyFiledName, keyFileValue.ToString()), doc); iw.Optimize(); } } /// <summary> /// 是否存在指定的索引文档 /// </summary> /// <param></param> /// <param></param> /// <param></param> /// <returns></returns> public static bool ExistsDocument(string indexDir, string keyFiledName, object keyFileValue) { FSDirectory directory = FSDirectory.Open(new DirectoryInfo(indexDir), new NativeFSLockFactory()); if (!IndexReader.IndexExists(directory)) { return false; } var reader = IndexReader.Open(directory, true); return reader.DocFreq(new Term(keyFiledName, keyFileValue.ToString())) > 0; } /// <summary> /// 查询索引匹配到的记录 /// </summary> /// <typeparam></typeparam> /// <param></param> /// <param></param> /// <param></param> /// <param></param> /// <param></param> /// <param></param> /// <returns></returns> public static List<TResult> SearchIndex<TResult>(string indexDir, Func<BooleanQuery, IDictionary<string, string>> buildQueryAction, Func<IEnumerable<SortField>> getSortFieldsFunc, Func<Document, TResult> buildResultFunc, bool needHighlight = true, int topCount = 0) { FSDirectory directory = FSDirectory.Open(new DirectoryInfo(indexDir), new NoLockFactory()); if (!IndexReader.IndexExists(directory)) { return new List<TResult>(); } IndexReader reader = IndexReader.Open(directory, true); IndexSearcher searcher = new IndexSearcher(reader); BooleanQuery bQuery = new BooleanQuery(); var keyWords = buildQueryAction(bQuery); Sort sort = null; var sortFields = getSortFieldsFunc(); if (sortFields != null) { sort = new Sort(); sort.SetSort(sortFields.ToArray()); } topCount = topCount > 0 ? topCount : int.MaxValue;//当未指定TOP值，则设置最大值以表示获取全部 TopDocs resultDocs = null; if (sort != null) { resultDocs = searcher.Search(bQuery, null, topCount, sort); } else { resultDocs = searcher.Search(bQuery, null, topCount); } if (topCount > resultDocs.TotalHits) { topCount = resultDocs.TotalHits; } Dictionary<string, PropertyInfo> highlightProps = null; List<TResult> results = new List<TResult>(); if (resultDocs != null) { for (int i = 0; i < topCount; i++) { Document doc = searcher.Doc(resultDocs.ScoreDocs[i].Doc); var model = buildResultFunc(doc); if (needHighlight) { model = SetHighlighter(keyWords, model, ref highlightProps); } results.Add(model); } } return results; } /// <summary> /// 分页查询索引匹配到的记录 /// </summary> /// <typeparam></typeparam> /// <param></param> /// <param></param> /// <param></param> /// <param></param> /// <param></param> /// <param></param> /// <param></param> /// <param></param> /// <returns></returns> public static List<TResult> SearchIndexByPage<TResult>(string indexDir, Func<BooleanQuery, IDictionary<string, string>> buildQueryAction, Func<IEnumerable<SortField>> getSortFieldsFunc, Func<Document, TResult> buildResultFunc, int pageSize, int page, out int totalCount, bool needHighlight = true) { FSDirectory directory = FSDirectory.Open(new DirectoryInfo(indexDir), new NoLockFactory()); if (!IndexReader.IndexExists(directory)) { totalCount = 0; return new List<TResult>(); } IndexReader reader = IndexReader.Open(directory, true); IndexSearcher searcher = new IndexSearcher(reader); BooleanQuery bQuery = new BooleanQuery(); var keyWords = buildQueryAction(bQuery); Sort sort = null; var sortFields = getSortFieldsFunc(); if (sortFields != null) { sort = new Sort(); sort.SetSort(sortFields.ToArray()); } TopScoreDocCollector docCollector = TopScoreDocCollector.Create(1, true); searcher.Search(bQuery, docCollector); totalCount = docCollector.TotalHits; if (totalCount <= 0) return null; TopDocs resultDocs = searcher.Search(bQuery, null, pageSize * page, sort); Dictionary<string, PropertyInfo> highlightProps = null; List<TResult> results = new List<TResult>(); int indexStart = (page - 1) * pageSize; int indexEnd = indexStart + pageSize; if (totalCount < indexEnd) indexEnd = totalCount; if (resultDocs != null) { for (int i = indexStart; i < indexEnd; i++) { Document doc = searcher.Doc(resultDocs.ScoreDocs[i].Doc); var model = buildResultFunc(doc); if (needHighlight) { model = SetHighlighter(keyWords, model, ref highlightProps); } results.Add(model); } } return results; } /// <summary> /// 设置结果高亮 /// </summary> /// <typeparam></typeparam> /// <param></param> /// <param></param> /// <param></param> /// <returns></returns> private static T SetHighlighter<T>(IDictionary<string, string> dicKeywords, T model, ref Dictionary<string, PropertyInfo> props) { SimpleHTMLFormatter simpleHTMLFormatter = new SimpleHTMLFormatter("<font color=\"red\">", "</font>"); Highlighter highlighter = new Highlighter(simpleHTMLFormatter, new Segment()); highlighter.FragmentSize = 250; Type modelType = typeof(T); foreach (var item in dicKeywords) { if (!string.IsNullOrWhiteSpace(item.Value)) { if (props == null) { props = new Dictionary<string, PropertyInfo>(); } if (!props.ContainsKey(item.Key)) { props[item.Key] = modelType.GetProperty(item.Key, BindingFlags.IgnoreCase | BindingFlags.Public | BindingFlags.Instance); } var modelProp = props[item.Key]; if (modelProp.PropertyType == typeof(string)) { string newValue = highlighter.GetBestFragment(item.Value, modelProp.GetValue(model).ToString()); if (!string.IsNullOrEmpty(newValue)) { modelProp.SetValue(model, newValue); } } } } return model; } /// <summary> /// 拆分关键词 /// </summary> /// <param></param> /// <returns></returns> public static string GetKeyWordsSplitBySpace(string keyword) { PanGuTokenizer ktTokenizer = new PanGuTokenizer(); StringBuilder result = new StringBuilder(); ICollection<WordInfo> words = ktTokenizer.SegmentToWordInfos(keyword); foreach (WordInfo word in words) { if (word == null) { continue; } result.AppendFormat("{0}^{1}.0 ", word.Word, (int)Math.Pow(3, word.Rank)); } return result.ToString().Trim(); } /// <summary> /// 【辅助方法】创建盘古查询对象 /// </summary> /// <param></param> /// <param></param> /// <returns></returns> public static Query CreatePanGuQuery(string field, string keyword, bool needSplit = true) { if (needSplit) { keyword = GetKeyWordsSplitBySpace(keyword); } QueryParser parse = new QueryParser(Lucene.Net.Util.Version.LUCENE_30, field, new PanGuAnalyzer()); parse.DefaultOperator = QueryParser.Operator.OR; Query query = parse.Parse(keyword); return query; } /// <summary> /// 【辅助方法】创建盘古多字段查询对象 /// </summary> /// <param></param> /// <param></param> /// <returns></returns> public static Query CreatePanGuMultiFieldQuery(string keyword, bool needSplit, params string[] fields) { if (needSplit) { keyword = GetKeyWordsSplitBySpace(keyword); } QueryParser parse = new MultiFieldQueryParser(Lucene.Net.Util.Version.LUCENE_30, fields, new PanGuAnalyzer()); parse.DefaultOperator = QueryParser.Operator.OR; Query query = parse.Parse(keyword); return query; } } }