用dotLucene为数据库内容建立索引

//建立索引的类        
public class Indexer
         {
             private IndexWriter writer;
             Document doc = new Document();

             public Indexer(string Directory)
             {
                 InitializeIndex(Directory);
             }

             public void InitializeIndex(string Directory)
             {
                 writer = new IndexWriter(Directory, new StandardAnalyzer(), true);
                 writer.SetUseCompoundFile(true);
             }

             public void AddDocument(string DateAdded , string Description , string URL , string Title )
             {
                 doc.Add(Field.Keyword("date", DateAdded));
                 doc.Add(Field.Text("description", Description));
                 doc.Add(Field.Text("url", URL));            
                 doc.Add(Field.Text("title", Title));
                 doc.Add(Field.Keyword("sortdate", ReturnSortDate(DateTime.Parse(DateAdded)).ToString()));
                 writer.AddDocument(doc);
             }
                         

             private int ReturnSortDate(DateTime DateAdded)
             {
                 string thisMonth = DateAdded.Month.ToString();

                 if (thisMonth.Length == 1)
                 {
                     thisMonth = "0" + thisMonth;
                 }

                 string thisYear   = DateAdded.Year.ToString();
                 string thisDay = DateAdded.Day.ToString();

                 if( thisDay.Length == 1 )
                 {
                     thisDay = "0" + thisDay;
                 }

                 int time = int.Parse(thisYear+thisMonth +thisDay);
                

                 return time;
             }

             public void Close()
             {
                 writer.Optimize();
                 writer.Close();
             }
         }

//搜索的类
public class Searcher
         {
             private IndexSearcher searcher;

             public Searcher(string Directory)
             {
                 searcher = new IndexSearcher(Directory);
             }

             public DataTable Search(string Query, string SortBy)
             {
                 DataTable Results = new DataTable();
                 Results.Columns.Add("Title");
                 Results.Columns.Add("Description");
                 Results.Columns.Add("URL");
                 Results.Columns.Add("Published");
            
                 Query MyQuery   = QueryParser.Parse(Query, "description", new StandardAnalyzer());
                 Sort   sort = new Sort(SortBy, true);
                 Hits Hits = searcher.Search(MyQuery, sort);

                 int mTotalRecs = Hits.Length();
                 int iCount = 0;
                 while (iCount < mTotalRecs)
                 {
                     Document doc = Hits.Doc(iCount);
                     DataRow row = Results.NewRow();
                     row["url"] = doc.Get("url");
                     row["Title"] = doc.Get("title");
                     row["Description"] = doc.Get("description");
                     row["Published"] = doc.Get("date");
                     Results.Rows.Add(row);

                     iCount++;
                 }

                 searcher.Close();
                 return Results;
             }
         }