我试图从hdfs读取json文件到文件流，我得到了一个异常。
私有字符串readhadoopjasonfiles（）{//set variables string destfoldername=“/demo/ufo/in”；string destfilename=“admingroups\u metadata.json”；

//connect to hadoop cluster
        Uri myUri = new Uri("http://localhost:50070");
        string userName = "hadoop";
        string srcFilename = destFolderName + "/" + destFileName;
        //string srcFilename = @"C:\FilesForHadoopJason\admingroups_metadata.xml";
        WebHDFSClient myClient = new WebHDFSClient(Convert.ToString(myUri), userName);

        FileStream fs = new FileStream(srcFilename, FileMode.Open, FileAccess.Read);
        StreamReader sr = new StreamReader(fs);
        string json;
        try
        {
            json = sr.ReadToEnd();
            string repalcedjson = json.Replace("\"", "'");
            return repalcedjson;

        }
        catch (Exception)
        {
            return null;
        }
        finally
        {
            sr.Close();
            fs.Dispose();
        }
    }

异常：system.io.directorynotfoundexception未处理hresult=-2147024893 message=找不到路径“c:\user\projects\poc\challengeOpenUMP20140701160001\u admingroups.json”的一部分。source=mscorlib stacktrace:at system.io.\u error.winioerror（int32 errorcode，string maybefullpath）at system.io.filestream.init（string path，filemode mode，fileaccess access，int32 rights，boolean userights，fileshare，int32 buffersize，fileoptions options，secattrs，string msgpath，boolean bfromproxy，boolean uselongpath，boolean checkhost）在system.io.filestream..ctor（字符串路径，文件模式，c:\users\dxg8488\documents\visual studio 2012\projects\consoleapplication1\consoleapplication1\program.cs中consoleapplication1.hadoopjsontordbms.readhadoopjasonfiles（）的文件访问权限：c:\users\dxg8488\documents\visual studio中consoleapplication1.hadoopjsontordbms.jsontordbmscontroller（）的第111行2012\projects\consoleapplication1\consoleapplication1\program.cs:c:\users\dxg8488\documents\visual studio 2012\projects\consoleapplication1\consoleapplication1\program.cs中consoleapplication1.hadoopjsontordbms.main的第29行。\u nexecuteassembly（runtimeassembly，位于system.threading.threadhelper.threadstart\ U上下文（对象状态）的system.appdomain.executeassembly（string assemblyfile，evidence assemblysecurity，string[]args）的microsoft.visualstudio.hostingprocess.hostproc.runusersassembly（）的string[]args，在system.threading.executioncontext.run（executioncontext executioncontext，contextcallback callback，object state，boolean preservesyncctx）在system.threading.executioncontext.run（executioncontext executioncontext，contextcallback callback，object state，boolean preservesyncctx）处，对象状态），位于system.threading.threadhelper.threadstart（）innerexception: