利用Boost影响Lucene查询结果的排序

以下代码在Lucene2.1下通过，主要是通过设置Document的Boost来影响文档的权重，以达到控制查询结果顺序的目的(前提是不利用Sort排序的情况下):


private void btnSearch_Click(object sender, EventArgs e)






{


RAMDirectory ramDir = new RAMDirectory();


IndexWriter iw = new IndexWriter(ramDir,new StandardAnalyzer(),true);






string[] NameList =

{ "you are my friend", "you are my wife", "I love you" };




string[] FileList =

{ "1", "2", "3" };




for (int i = 0; i < NameList.Length; i++)






{


Document doc = new Document();


doc.Add(new Field("name", NameList[i], Field.Store.YES, Field.Index.TOKENIZED));


doc.Add(new Field("file", FileList[i], Field.Store.YES, Field.Index.TOKENIZED));






if (i == 2)

{ doc.SetBoost(2.0f); }//这里设置了第三个文档优先级最高，所以在搜索出来的结果中，该文档排在最前


iw.AddDocument(doc);


}


iw.Close();




IndexSearcher _searcher = new IndexSearcher(ramDir);


QueryParser _parser = new QueryParser("name",new StandardAnalyzer());


Query _query = _parser.Parse("you");


Hits hitDoc = _searcher.Search(_query);




lstResult.Items.Clear();//lstResult为一个ListBox




for (int i = 0; i < hitDoc.Length(); i++)






{


Document doc = hitDoc.Doc(i);


lstResult.Items.Add(doc.Get("file") + " " + doc.Get("name"));


}


_searcher.Close();


}
以下是运行结果