FTP上傳 - 內存泄漏問題

Question

我正在使用FTP協議上傳和下載大文件的個人項目。除了我最近注意到的內存泄漏外，它工作正常。我不清楚問題是什麼。這可能是內存泄漏或編程不當。此應用程序使用的內存量在上傳時每秒增加。這裏是代碼：

Action action; 
    int bufferSize = 16384; 
    EventLogger elog = new EventLogger(); 
    string error = ""; 
    string filename = ""; 

    public Uploader(Action action) 
    { 
     this.action = action; 
     filename = action.directory.Substring(action.directory.LastIndexOf('\\') + 1, 
      action.directory.Length - action.directory.LastIndexOf('\\') - 1); 
    } 

    public bool startUpload() 
    { 
     try 
     { 
      FtpWebRequest request = (FtpWebRequest)WebRequest.Create("ftp://*******"); 
      request.Method = WebRequestMethods.Ftp.ListDirectory; 
      request.Credentials = new NetworkCredential("***", "***"); 

      FtpWebResponse response = (FtpWebResponse)request.GetResponse(); 

      Stream responseStream = response.GetResponseStream(); 
      StreamReader reader = new StreamReader(responseStream); 
      List<string> files = new List<string>(); 
      string[] filesArr = reader.ReadToEnd().Split('\n'); 
      reader.Close(); 
      response.Close(); 
      foreach (string file in filesArr) 
       files.Add(file.Replace("\r", "")); 
      if (files.IndexOf(filename) != -1) 
      { 
       request = (FtpWebRequest)WebRequest.Create("ftp://***/"+filename); 
       request.Method = WebRequestMethods.Ftp.DeleteFile; 
       request.Credentials = new NetworkCredential("***", "***"); 
       response = (FtpWebResponse)request.GetResponse(); 
       reader.Close(); 
       response.Close(); 
       if (response.StatusCode != FtpStatusCode.FileActionOK) 
       { 
        return false; 
       } 
      } 

      request = (FtpWebRequest)WebRequest.Create("ftp://***/"+filename); 
      request.Method = WebRequestMethods.Ftp.UploadFile; 
      request.KeepAlive = false; 
      request.UseBinary = true; 

      FileStream stream = File.OpenRead(action.directory); 
      byte[] buffer = new byte[bufferSize]; 
      Stream reqStream = request.GetRequestStream(); 

      SqlCommand cmd = new SqlCommand(); 
      cmd.CommandText = "update DIRECT_UPLOAD set COMPLETED = @com, PROGRESS = @prog, SPEED = @speed where ID = @id"; 
      cmd.Parameters.AddWithValue("@id", action.id); 
      cmd.Parameters.AddWithValue("@com", 0); 
      cmd.Parameters.AddWithValue("@prog", 0); 
      cmd.Parameters.AddWithValue("@speed", 0); 


      long i = 0; 
      int readed = 0; 
      int total = 0; 
      int speed = 0; 
      DateTime last = DateTime.Now; 
      int lastTotal = 0; 
      while ((readed = stream.Read(buffer, 0, bufferSize)) > 0) 
      { 
       reqStream.Write(buffer, 0, readed); 
       total += readed; 
       if (i % 100 == 0) 
       { 
        cmd.Parameters["@com"].Value = total; 
        cmd.Parameters["@prog"].Value = (int)(((double)total/action.size) * 100); 
        int tot = 0; 
        tot = total - lastTotal; 
        int time = Convert.ToInt32((DateTime.Now - last).TotalMilliseconds); 
        speed = (int)(((double)1000.0/time) * tot); 
        cmd.Parameters["@speed"].Value = speed; 
        if ((error = SqlProcess.sqlNonQuery(cmd)) != "") 
         throw new Exception(error); 
        last = DateTime.Now; 
        lastTotal = total; 
       } 

       Application.DoEvents(); 
       i++; 
      } 

      cmd.Parameters["@com"].Value = total; 
      cmd.Parameters["@prog"].Value = 100; 
      cmd.Parameters["@speed"].Value = 0; 
      if ((error = SqlProcess.sqlNonQuery(cmd)) != "") 
       throw new Exception(error); 

      reqStream.Close(); 
      stream.Close(); 
     } 
     catch (Exception ex) 
     { 
      elog.write(ex); 
      return false; 
     } 
     return true; 
    } 

謝謝。

Answer 1

檢查你在這裏使用的所有對象，以確保它們不需要是Dispose-d（即它們是否實現了IDisposable？）。否則，每次執行代碼時，都會遇到與每個對象關聯的非託管資源泄漏。

您可以使用using以異常安全的方式整理確保爲此類對象調用Dispose()。舉例

- 而不是：

SqlCommand cmd = new SqlCommand(); 

使用這種包裝使用cmd

using (SqlCommand cmd = new SqlCommand()) 
{ 
} 

請注意，您EventLogger類也可能需要實現IDisposable如果它是一個封裝了自定義類的代碼通過（例如）File或EventLog的非託管資源。

您可以在MSDN文檔中檢查您在程序中的其他內置類中使用的其他內置類。