DotLucene搜索引擎Demo之:搜索索引
在上篇文章我们说了怎么建立索引,现在说的是怎么搜索这个索引,最主要的我们是要理解startAt的含义,理解了他什么问题都解决了。还有这个例子的分页很经典,我发现google和baidu用的都是这个分页方法。主要就两个方法,一个search()方法,主要是显示当前页的搜索记录
注:本文转自http://www.cnblogs.com/pwqzc/archive/2006/03/16/351167.html
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protected void search()
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{
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DateTime start = DateTime.Now;//搜索的开始时间
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//得到索引所在的目录,我们在上个console程序里把索引放到了index目录下
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string indexDirectory = Server.MapPath("index");
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//创建个索引搜索器
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IndexSearcher searcher = new IndexSearcher(indexDirectory);
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//分词并解析索引的text字段以便搜索
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Query thisQuery = QueryParser.Parse(this.Query,"text",new StandardAnalyzer());
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//为要绑定输出到页面的results建立几列
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this.Results.Columns.Add("path",typeof(string));
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this.Results.Columns.Add("sample",typeof(string));
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this.Results.Columns.Add("title",typeof(string));
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//开始搜索
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Hits hits = searcher.Search(thisQuery);
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//得到搜索返回的记录总数
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this.total = hits.Length();
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//创建一个高亮
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QueryHighlightExtractor highlighter = new QueryHighlightExtractor(thisQuery, new StandardAnalyzer(), "<B>", "</B>");
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//初始化startAt,以便得到要显示的结果集
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this.startAt = initStartAt();
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//得到当前页要显示的记录数量,包括以前所有页的记录数,这样把他与this.startAt结合就能够很好的知道当前页要显示的记录数了
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int resultsCount = smallOf(this.total,this.startAt+this.maxResults);
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//开始循环得到当前页要显示的记录
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for (int i = this.startAt; i < resultsCount; i++)
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{
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//得到每一行Hits的Document,因为Hits的没一行都是个Document对象
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Document doc = hits.Doc(i);
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//得到doc里面的列path的值
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string path = doc.Get("path");
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//再得到这个路径在web程序的路径,我们原来把文档放到了web根目录的documents目录下的
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string location = Server.MapPath(@"documents\"+path);
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//用StreamReader读取文档,因为我们不能够直接从索引中得到text字段的值,因为我们建立索引的时候没有存储他的
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string plainText;
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using (StreamReader sr = new StreamReader(location, System.Text.Encoding.Default))
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{
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plainText = ParseHtml(sr.ReadToEnd());
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}
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//为结果集DataTable,Results添加个新行
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DataRow dr = this.Results.NewRow();
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dr["title"] = doc.Get("title");
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dr["path"] = @"documents/" + path;
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dr["sample"] = highlighter.GetBestFragment(plainText,80);
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//把行添加进DataTable
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this.Results.Rows.Add(dr);
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}
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//循环完毕,关闭搜索
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searcher.Close();
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//搜索花费多少时间
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this.duration = DateTime.Now - start;
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//给fromItem赋值,他总是startAt+1
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this.fromItem = this.startAt + 1;
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//给toItem赋值
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this.toItem = smallOf(this.total,this.startAt+this.maxResults);
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}
还有就是一个Paging属性,他的作用就是分页,输出分页的html这个属性很经典
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/// <summary>
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/// 开始分页
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/// </summary>
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/// <returns></returns>
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protected DataTable Paging
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{
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get
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{
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//知道了startAt,分页也很容易了,现在根据startAt得到当前是第几页,注意,现在这里的页数也是暂时从0开始的
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int pageNumber = (this.startAt + this.maxResults - 1) / this.maxResults;
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DataTable dt = new DataTable();
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dt.Columns.Add("html");
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DataRow dr = dt.NewRow();
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//暂时得到当前页的html连接,注意这里当真正显示页数的时候要+1
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dr["html"] = pagingNumberHtml(startAt,pageNumber+1,false);
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dt.Rows.Add(dr);
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//前面显示10页,如果有的话
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int previousPagesCount = 10;
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//循环把前面页的html连接插到前面去
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for (int i = pageNumber - 1; i >= 0 && i >= pageNumber - previousPagesCount; i--)
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{
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DataRow r = dt.NewRow();
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r["html"] = pagingNumberHtml(i*this.maxResults,i+1,true);
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dt.Rows.InsertAt(r,0);;
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}
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//后面也显示10页,如果有的话
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int nextPagesCount = 10;
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for (int i = pageNumber + 1; i <= this.pageCount && i <= pageNumber + nextPagesCount; i++)
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{
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DataRow r = dt.NewRow();
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r["html"] = pagingNumberHtml(i*this.maxResults,i+1,true);
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dt.Rows.Add(r);
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}
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//添加下一页的超级连接
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DataRow lastRow = dt.NewRow();
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lastRow["html"] = "<a href='Search.aspx?q="+this.Query+"&start="+(pageNumber+1)*this.maxResults+"'>下一页</a>";
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dt.Rows.Add(lastRow);
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return dt;
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}
点这里开始下载这两篇文章的源代码
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注:本文转自http://www.cnblogs.com/pwqzc/archive/2006/03/16/351167.html
本文来自博客园,作者:古道轻风,转载请注明原文链接:https://www.cnblogs.com/88223100/archive/2008/08/18/1270652.html
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