盘古搜索--实例解析

1.引用

PanGu.dll

Lucene.Net.dll

PanGu.Lucene.Analyzer.dll

PanGu.HighLight.dll--高亮使用

 

2.Dict文件夹

文件夹名称一定要为Dict,并且设置“如果较新则复制”

 

3.创建索引部分。

思路：把添加的消息放在redis队列中，从队列中读取消息，并且添加索引。

利用线程读队列然后一条一条写入索引。

写入索引的部分通常是单独项目中，因为写入索引会非常耗内存

public class MessageIndex
    {
        Thread thread;
        public bool IsRunning { get; set; }
        public void Start()
        {
            IsRunning = true;
            thread = new Thread(RunScan);//线程开始就不断的从队列中取出消息,，先取消息再写入索引
            thread.IsBackground = false;//后台线程，关闭程序就退出
            thread.Start();
        }
        public void RunScan()
        {
            while (IsRunning)
            {
                using (var client = RedisManager.ClientManager.GetClient())
                {
                    StartIndex(client);//读出消息后取出写入索引
                }
            }
        }
        public void StartIndex(IRedisClient client)
        {
            FSDirectory directory = null;
            IndexWriter writer = null;
            try
            {
                string indexPath = @"F:	mpindex2";//注意和磁盘上文件夹的大小写一致，否则会报错。索引保存位置
                directory = FSDirectory.Open(new DirectoryInfo(indexPath), new NativeFSLockFactory());
                bool isExists = IndexReader.IndexExists(directory);
                if (isExists)
                {
                    //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
                    //Lucene.Net在写索引库之前会自动加锁，在close的时候会自动解锁
                    //不能多线程执行，只能处理意外被永远锁定的情况
                    if (IndexWriter.IsLocked(directory))
                    {
                        IndexWriter.Unlock(directory);//强制解锁
                    }
                }
                writer = new IndexWriter(directory, new PanGuAnalyzer(), !isExists, Lucene.Net.Index.IndexWriter.MaxFieldLength.UNLIMITED);
                //从redis队列中取出数据
                while (true)
                {
                    string json = client.DequeueItemFromList("QiuShiBaiKe.Message");
                    //取出可能为null
                    if (string.IsNullOrEmpty(json))
                    {
                        Thread.Sleep(3000);//
                        return;//没有消息可读就return
                    }
                    else
                    {
                        //反序列化
                        Message message = new JavaScriptSerializer().Deserialize<Message>(json);
                        WriteIndex(message, writer);
                        
                    }
                  
                }
            }
            catch (Exception)
            {
                throw new Exception("写入索引出错");
            }
            finally
            {
                writer.Close();
                directory.Close();//不要忘了Close，否则索引结果搜不到
            }
        }
        /// <summary>
        /// 写入索引
        /// </summary>
        /// <param name="message"></param>
        private void WriteIndex(Message message, IndexWriter writer)
        {
            //将重复的字段删掉
            writer.DeleteDocuments(new Term("id", message.Id.ToString()));
            //添加记录
            Document document = new Document();//一条Document相当于一条记录
            document.Add(new Field("id", message.Id.ToString(), Field.Store.YES, Field.Index.NOT_ANALYZED));//每个Document可以有自己的属性（字段），所有字段名都是自定义的，值都是string类型
            document.Add(new Field("message", message.Msg, Field.Store.YES, Field.Index.ANALYZED, Lucene.Net.Documents.Field.TermVector.WITH_POSITIONS_OFFSETS));
            writer.AddDocument(document);//insert into...插入一条记录，有两个字段：number和body
            Console.WriteLine("id="+message.Id.ToString()+"msg="+message.Msg);
        }
    }

在索引的主程序中，调用

MessageIndex messageIndex = new MessageIndex();
 messageIndex.Start();

4.搜索部分--使用MVC框架

1）分词方法：

//分词
        static public string GetKeyWordsSplitBySpace(string keywords, PanGuTokenizer ktTokenizer)
        {
            StringBuilder result = new StringBuilder();
            ICollection<WordInfo> words = ktTokenizer.SegmentToWordInfos(keywords);
            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();
        } 
2）搜索并且对结果高亮显示
 //搜索
        public static List<SearchResult> SearchResult(String indexDir, String q, int pageLen, int pageNo, out int recCount)
        {
            string keywords = q;
            IndexSearcher search = new IndexSearcher(indexDir);
            q = GetKeyWordsSplitBySpace(q, new PanGuTokenizer());
            QueryParser queryParser = new QueryParser("message", new PanGuAnalyzer(true));
            Query query = queryParser.Parse(q);//在message中搜索keyword
            //当然这里可以添加多个搜索条件
            //QueryParser titleQueryParser = new QueryParser("title", new PanGuAnalyzer(true));
            //Query titleQuery = titleQueryParser.Parse(q);
            BooleanQuery bq = new BooleanQuery();
            bq.Add(query, BooleanClause.Occur.SHOULD);
            //bq.Add(titleQuery, BooleanClause.Occur.SHOULD);
            Hits hits = search.Search(bq);
            List<SearchResult> results = new List<SearchResult>();
            recCount = hits.Length();//搜索结果的总条数
            int i = (pageNo - 1) * pageLen;
            while (i < recCount && results.Count < pageLen)//这里是一个分页处理
            {
                SearchResult result = null;
                try
                {
                    result = new SearchResult();
                    result.Message = hits.Doc(i).Get("message");
                    result.MessageUrl = "/Message/PreviewMessage/" + hits.Doc(i).Get("id");
                    //news.Url = hits.Doc(i).Get("url");
                    //String strTime = hits.Doc(i).Get("time");
                    //news.Time = DateTime.ParseExact(strTime, "yyyyMMdd", null);
                    PanGu.HighLight.SimpleHTMLFormatter simpleHTMLFormatter =
                        new PanGu.HighLight.SimpleHTMLFormatter("<font color="red">",
"</font>");
                    PanGu.HighLight.Highlighter highlighter =
                        new PanGu.HighLight.Highlighter(simpleHTMLFormatter,
                        new Segment());
                    highlighter.FragmentSize = 50;
                    result.MessageHightLigther = highlighter.GetBestFragment(keywords, result.Message);//高亮显示的消息
                    //news.TitleHighLighter = highlighter.GetBestFragment(keywords, news.Title);
                    if (string.IsNullOrEmpty(result.MessageHightLigther))
                    {
                        result.MessageHightLigther = result.Message;
                    }
                }
                catch (Exception e)
                {
                    Console.WriteLine(e.Message);
                }
                finally
                {
                    results.Add(result);
                    i++;
                }
            }
            search.Close();
            return results;
        } 

3）搜索结果的类

 public class SearchResult
    {
        public string Message { get;set;}//消息
        public string MessageUrl { get; set; }//消息详细页链接
        public string MessageHightLigther { get; set; }//高亮显示的消息
    }

4）在Controller中的主代码

public ActionResult Search(string keyword, int? pageIndex)
        {
            if (pageIndex==null)
            {
                pageIndex = 1;
            }
            if (pageIndex<=0)
            {
               return View("Error", (object)"pageIndex必须大于0");
            }
            int totalCount;
          List<SearchResult>results=  SearchResult(@"F:	mpindex2", keyword, 3, (int)pageIndex, out totalCount);
            ViewBag.KeyWord = keyword;
            ViewBag.SearchResults = results;
            ViewBag.TotalCount = totalCount;//总结果条数
            ViewBag.PageIndex = pageIndex;
            ViewBag.PageSize = 3;
            return View();
        }

5）Search View中的代码

@{
    ViewBag.Title = "搜索" + ViewBag.KeyWord;
    Layout = "~/Views/DefaultLayout.cshtml";
}
@{
    foreach (var result in ViewBag.SearchResults)
    {
    <div >
        <a href="@result.MessageUrl" target="_blank">@(new HtmlString(result.MessageHightLigther))</a>
    </div>
    
    }
}
@QiuShiBaiKe.Web.WebHelper.Pager("/Message/Search/{pageIndex}/"+ViewBag.KeyWord, ViewBag.TotalCount, ViewBag.PageIndex, ViewBag.PageSize)

6）搜索的路由配置

//搜索路由
            routes.MapRoute(
              name: "search",
              url: "{controller}/{action}/{pageIndex}/{keyword}",
              defaults: new { controller = "Message", action = "Search", pageIndex = UrlParameter.Optional, keyword=UrlParameter.Optional }
          );