NHibernate.Search现在是NHiberante Contrilb下面的一个还没有发布的项目,也是从Hibernate.Search移植而来,把NHibernate和Lucene.NET结合在一起,ORM持久化对象到数据库中,Lucene.NET提供索引及查询支持.
     下面在实际使用一下NHibernate.Search的使用:
     由于这个项目还没有发布,它的很多特性也是一直在变化,所以现在只是以我下载的版本为准,如果你想尝试此项目,请下载最下面的代码,里面包括自己编译生成的NHibernate.Search及最新的Lucene.net相关的dll.

一.配置
    1.修改你的NHibernate配置信息的地方,同样添加NHibernate.Search的配置信息.

<configSections>
<section name="hibernate-configuration" type="NHibernate.Cfg.ConfigurationSectionHandler, NHibernate"/>
<section name="nhs-configuration" type="NHibernate.Search.Cfg.ConfigurationSectionHandler, NHibernate.Search" requirePermission="false" />
<sectionGroup name="system.web.extensions" type="System.Web.Configuration.SystemWebExtensionsSectionGroup, System.Web.Extensions, Version=3.5.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35">
.....
</configSections>        需要注意的是,在NHibernate.Search之前的版本中,曾经NHibernate.Search的配置信息和NHIbernate的放在一起.接下来,我们来看下具体的配置块:

 <hibernate-configuration xmlns="urn:nhibernate-configuration-2.2">
        <bytecode-provider type="lcg"/>
        <reflection-optimizer use="true"/>
        <session-factory name="NHibernateSearch.Demo">
            <property name="connection.provider">NHibernate.Connection.DriverConnectionProvider, NHibernate</property>
            <property name="connection.connection_string">
                Data Source=|DataDirectory|Demo.db3;Version=3;Compress=False;synchronous=OFF
            </property>
            <property name="show_sql">true</property>
            <property name="dialect">NHibernate.Dialect.SQLiteDialect</property>
            <property name="connection.driver_class">NHibernate.Driver.SQLite20Driver</property>
            <property name="prepare_sql">true</property>
            <property name="cache.provider_class">NHibernate.Cache.HashtableCacheProvider, NHibernate</property>
            <property name="cache.use_query_cache">true</property>
            <mapping assembly="NHibernateSearch.Demo.Model"/>
        </session-factory>
    </hibernate-configuration>
 <nhs-configuration xmlns='urn:nhs-configuration-1.0'>
        <search-factory  sessionFactoryName="NHibernateSearch.Demo">
            <property name='hibernate.search.default.directory_provider'>NHibernate.Search.Store.
FSDirectoryProvider, NHibernate.Search</property>
            <property name='hibernate.search.default.indexBase'>~/Index</property>
            <property name='hibernate.search.default.indexBase.create'>true</property>
        </search-factory>
    </nhs-configuration>     上面的是NHibernate的配置信息,由于我在示例程序中使用的是SQLite数据库,所以这个Demo也是一个SQLite+NHibernate的案例,而且里注意SQLite的连接字符串Data Source=|DataDirectory|Demo.db3,这样的话,只要把数据文件放在App_Data下面就可以运行了,而不用再去填写数据库文件的绝对路径.
     下面是NHibernate.Search的配置,我们采用基于文件目录的全文检索,索引文件放在根目录下面的Index文件夹下面.
     另外,我们设置一下NHibernate的事件监听(如果不我们设置的话,我们要手动去调用,才能够使NHibernate在持久化对象时,同时处理全文索引),现在这个事件配置还不支持直接在NHibernate这样配置:

         <listener class='NHibernate.Search.Event.FullTextIndexEventListener, NHibernate.Search' type='post-insert'/>

         <listener class='NHibernate.Search.Event.FullTextIndexEventListener, NHibernate.Search' type='post-update'/>

        <listener class='NHibernate.Search.Event.FullTextIndexEventListener, NHibernate.Search' type='post-delete'/>
      现在我们只能在创建SessionFactory前,手动添加这个配置信息:

               Configuration configuration = new Configuration();
                configuration.SetListener(NHibernate.Event.ListenerType.PostUpdate, new FullTextIndexEventListener());
                configuration.SetListener(NHibernate.Event.ListenerType.PostInsert, new FullTextIndexEventListener());
                configuration.SetListener(NHibernate.Event.ListenerType.PostDelete, new FullTextIndexEventListener());
                configuration.Configure();
                sessionFactory=  configuration.BuildSessionFactory();      我们为更新,删除,添加都配置了全文索引的事件监听,这样就能够保证索引文件里的数据和实际数据库里的保持一致,不要担心,这的性能也有考虑,这里可以支持最大提交数量,而不一定非要每条操作都去更改索引文件.

二.使用
      首先我们要在NHibernate实体对象这里添加一些NHibernate.Search的一些关于全文索引的属性声明.不知道这里以后会不会支持xml的配置而不是修改原来的对象代码.

    [Indexed(Index = "Book")]
    public class Book
    {
        [DocumentId]
        public  virtual string BookID
        {
            get;
            set;
        }
        [Field(Index.Tokenized, Store = Store.Yes)]
        public virtual string Title
        {
            get;
            set;
        }
        [Field(Index.Tokenized, Store = Store.Yes)]
        public virtual string Authors
        {
            get;
            set;
        }
        [Field(Index.Tokenized, Store = Store.Yes)]
        public virtual string Publisher
        {
            get;
            set;
        }
        [Field(Index.Tokenized, Store = Store.Yes)]
        public virtual string Summary
        {
            get;
            set;
        }
    }     用过Lucene.Net的朋友们可能会发现,其实这些标识,原来在不使用NHibernate时是直接针对字段的.而现在只是针对一个业务对象的属性.这样的话,但数据添加或者更改时,就会自动的进行索引,但数据进行删除时,也自动更新索引,而可以不进行人为的干预.
    上面是一个对象Book,其中包含名称,作者,出版社,简介.我们要想实现对这几个属性进行全文检索的话,以前只能够同时拼几个LiKE,如果针对数据库,数据库数据的话肯定性能不会好,但是如果针对索引文件就不一样了.首先我们看一下怎么来实现搜索:
    

public   static IList<BookSearchResult>  FindBooks(string query)
        {
            IList<BookSearchResult> results = new List<BookSearchResult>();
            Analyzer analyzer = new Lucene.Net.Analysis.Standard.StandardAnalyzer();
   MultiFieldQueryParser parser = new MultiFieldQueryParser(new string[] { "Title", "Summary", "Authors", "Publisher"    },         analyzer);
            Query queryObj;
            try
            {
                queryObj = parser.Parse(query);
            }
            catch (ParseException)
            {
                return results;
            }
            IFullTextSession session = Search.CreateFullTextSession(NHibernateHelper.GetCurrentSession());
                        ///1
            System.Type targetType = typeof(Book);
            IQuery nhQuery = session.CreateFullTextQuery(queryObj, new Type[] { targetType });
            IList<Book> books = nhQuery.List<Book>();

            NHibernate.Cfg.Configuration  cf =  new Configuration().Configure();
            SearchFactoryImpl searchFactory   = SearchFactoryImpl.GetSearchFactory(cf);
            IDirectoryProvider provider = searchFactory.GetDirectoryProviders(targetType)[0];

            Workspace workspace = new Workspace(searchFactory);
            IndexReader indexReader = workspace.GetIndexReader(provider, targetType);
            Query simplifiedQuery = queryObj.Rewrite(indexReader);
            SimpleHTMLFormatter formatter = new SimpleHTMLFormatter("<b class='term'>", "</b>");

            Highlighter hTitle = GetHighlighter(simplifiedQuery, formatter, "Title", 100);
            Highlighter hSummary = GetHighlighter(simplifiedQuery, formatter, "Summary", 200);
            Highlighter hAuthors = GetHighlighter(simplifiedQuery, formatter, "Authors", 100);
            Highlighter hPublisher = GetHighlighter(simplifiedQuery, formatter, "Publisher", 100);

            foreach (Book book in books)
            {
                BookSearchResult result = new BookSearchResult(book);

                TokenStream tsTitle = analyzer.TokenStream("Title", new System.IO.StringReader(book.Title ?? string.Empty));
                result.HighlightedTitle = hTitle.GetBestFragment(tsTitle, book.Title);

TokenStream tsAuthors = analyzer.TokenStream("Authors", new System.IO.StringReader(book.Authors ?? string.Empty));
                result.HighlightedAuthors = hAuthors.GetBestFragment(tsAuthors, book.Authors);

 TokenStream tsPublisher = analyzer.TokenStream("Publisher", new System.IO.StringReader(book.Publisher ??                string.Empty));
                result.HighlightedPublisher = hPublisher.GetBestFragment(tsPublisher, book.Publisher);

TokenStream tsSummary = analyzer.TokenStream("Summary", new System.IO.StringReader(book.Summary ?? string.Empty));
result.HighlightedSummary = hSummary.GetBestFragments(tsSummary, book.Summary, 3, " ... <br /><br /> ... ");

                results.Add(result);
            }
            return results;
        }      相信使用过Lucene.Net的朋友对上面的代码并不难理解,所有使用IFullTextSession的操作,都会进行全文索引的处理.另外这里还有多字段解析和分词的技术,就不详细介绍了.上面还使用了对查询关键字进行高亮显示,其中的BookSearchResult实体也只是对Book进行了包装,进行了显示的一些处理.具体请查看源代码.
      你可以在上面注释的///1处,添加对Book的一些操作,就可以显示的查看索引文件是否也同时进行了更新了.

二.结果
     下载直接运行整个项目,输入”程序”关键字,你会发现,在很短时间内,列出来了符合的记录,并黑色显示匹配的字(至于与不进行索引的搜索性能对比,留给以后再做吧):