Lucene.net 实现全文搜索

Lucene.net 实现全文搜索(2)     {
        /**/////索引写入器
        private IndexWriter writer;

        //要写入索引的文件的根目录
        private string docRootDirectory;

        //要匹配的文件格式
        private string[] pattern;

        /**//// <summary>
        /// 初始化一个索引写入器writer，directory为创建索引的目录，true代表如果不存在索引文件将重新创建索引文件，如果已经存在索引文件将覆写索引文件
        /// </summary>
        /// <param name="directory">传入的要创建索引的目录，注意是字符串值，如果目录不存在，他将会被自动创建</param>
        public IntranetIndexer(string directory)
        {
            writer = new IndexWriter(directory, new StandardAnalyzer(), true);
            writer.SetUseCompoundFile(true);
        }
       
        public void AddDirectory(DirectoryInfo directory, string [] pattern)
        {
            this.docRootDirectory = directory.FullName;
            this.pattern = pattern;
            addSubDirectory(directory);
        }
       
        private void addSubDirectory(DirectoryInfo directory)
        {