lucene.net 如何新增文档？

上一篇讲了如何在lucene.net 中建索引目录，建立索引，以及文档。本次是主要是提供一个新增doc的方法public void makeNewsSearchDocument(object sender, System.EventArgs e)  {   Analyzer analyzer = new StandardAnalyzer();   Directory directory = FSDirectory.GetDirectory(@"c:/tmp/testindex",false);// 对同一索引目录这里参数必须是false   IndexWriter iwriter = new IndexWriter(directory, analyzer,false);//索引的写入同样也是false   Document doc = new Document();   doc.Add(Field.Keyword("nid","3"));   doc.Add(Field.Text("title","我是一个人2"));    doc.Add(Field.UnStored("content","请输入你是一个好人的理由2"));    doc.Add(Field.Keyword("addtime",mydate));   doc.Add(Field.UnStored("other", "nothing2"));    String newsUrl = "/news/viewhtml/test2.htm";    doc.Add(Field.UnIndexed("visiturl", newsUrl));   iwriter.AddDocument(doc);   iwriter.Close();  }