正确处理WebRequest和StreamReader

Question

在从客户端方法getRecords调用ReadToEnd方法期间,我得到一个对象处理异常,该方法使用StreamReader与Web服务器通信.

对getRecords的第一次调用成功,只是在后续调用期间发生异常,因此我没有正确关闭和处理StreamReader和关联的WebRequest.

我知道我可以将这两个对象包装在using语句中,但是它只是扩展为try/catch/finally语句.从我下面的代码中可以看出,我正在清理我的finally子句.

因此,我要么不做使用声明所做的事情,要么在我的最终声明中还有其他一些我可能遗漏的东西.如果可能的话,我宁愿不使用using语句,因为我喜欢我的代码显式.

这是代码和相关的异常:

    public int getRecords(string[] args, string[] vals)
    {
        List<string> urlList = BuildUrlRequestStrings(args, vals); 

        WebRequest request = null;
        WebResponse wresponse = null;
        StreamReader sr = null;           

        foreach (string url in urlList)
        {   
            request = WebRequest.Create(url);

            request.Method = "GET";
            request.ContentType = "application/json";
            //request.Timeout = -1;
            request.Timeout = 300000;
            request.Credentials = CredentialCache.DefaultCredentials;
            //request.ContentType = "application/xml";

            try
            {
                wresponse = request.GetResponse();

                /*using (StreamReader sr = new StreamReader(wresponse.GetResponseStream()))
                {
                    _recieveBuffer = sr.ReadToEnd().ToString();
                }*/
                sr = new StreamReader(wresponse.GetResponseStream());
                _recieveBuffer = sr.ReadToEnd();

                //List<T> temp = JsonConvert.DeserializeObject<List<T>>(_recieveBuffer);
                List<T> temp = JsonConvert.DeserializeObject<List<T>>(
                    _recieveBuffer,
                    new JsonSerializerSettings { TypeNameHandling = TypeNameHandling.All }
                );

                _recieveData.AddRange(temp);                    
            }
            catch (WebException ex)
            {
                if (ex.Response != null)
                {
                    // can use ex.Response.Status, .StatusDescription         
                    if (ex.Response.ContentLength != 0)
                    {
                        using (var stream = ex.Response.GetResponseStream())
                        {
                            using (var reader = new StreamReader(stream))
                            {
                                Log.Info(FIDB.TAG1, "   WSBuffer.getRecords: WEBSERVER MESSAGE: " + reader.ReadToEnd());
                            }
                        }
                    }
                }

                return -1;
            }
            finally
            {
                if (sr != null)
                {
                    sr.Close();
                    sr.Dispose();
                }

                if (wresponse != null)
                {
                    wresponse.Close();
                    wresponse.Dispose();
                }
            }
        }

        return _recieveData.Count;
    }

---

07-02 11:32:15.076:I/<<< FI >>>(2775):StorageRelayService.RequestQueueThread:EXCEPTION:System.ObjectDisposedException:对象在被处理后使用.07-02 11:32:15.076:I/<<< FI >>>(2775):在System.Net.WebConnection.BeginRead(System.Net.HttpWebRequest请求,System.Byte []缓冲区,Int32偏移量,Int32大小,System.AsyncCallback cb,System.Object state)[0x00000] in:0 07-02 11:32:15.076:I/<<< FI >>>(2775):at System.Net.WebConnectionStream.BeginRead(System. Byte [] buffer,Int32 offset,Int32 size,System.AsyncCallback cb,System.Object state)[0x00000] in:0 07-02 11:32:15.076:I/<<< FI

(2775):在System.Net.WebConnectionStream.Read(System.Byte []缓冲区,Int32偏移量,Int32大小)[0x00000] in:0 07-02 11:32:15.076:I/<<< FI >>> (2775):在System.IO.StreamReader.ReadBuffer()[0x00000]中:0 07-02 11:32:15.076:I/<<< FI >>>(2775):at System.IO.StreamReader.Read (System.Char [] buffer,Int32 index,Int32 count)[0x00000] in:0 07-02 11:32:15.076:I/<<< FI(2775):at System.IO.StreamReader.ReadToEnd()[ 0x00000] in:0 07-02 11:32:15.076:I/<<< FI >>>(2775):at FieldInspection.Shared.Buffer.WSBuffer 1[FieldInspection.Shared.Model.AggregateRoot.Parcel].getRecords (System.String[] args, System.String[] vals) [0x00000] in <filename unknown>:0 07-02 11:32:15.076: I/<<< FI >>>(2775): at FieldInspection.Shared.Repository.REST.RepositoryREST1 [FieldInspection.Shared.Model.AggregateRoot.Parcel] .Read( IConditions条件)[0x00000] in:0 07-02 11:32:15.076:I/<<< FI >>>(2775):at FieldInspection.Shared.Model.DataAccess.ParcelRepositoryREST.parcelByIdList(System.Collections.Generic.列表1 parcelIdList, Boolean bCurrent, Boolean bHistorical) [0x00000] in <filename unknown>:0 07-02 11:32:15.076: I/<<< FI >>>(2775): at FieldInspection.Droid.StorageRelayService.ProcessRequestGetParcelCache (FieldInspection.Shared.Database.IPC.Request request) [0x00000] in <filename unknown>:0 07-02 11:32:15.076: I/<<< FI >>>(2775): at FieldInspection.Droid.StorageRelayService.ProcessRequestFromForegroundActivity (System.Collections.Generic.List1 reqList)[0x00000] in:0 07-02 11:32:15.076:I/<<< FI >>>(2775):在FieldInspection.Droid.StorageRelayService.RequestQueueThread()[0x00000] in:0

Answer 1

using一旦失去范围，使用它将关闭您的连接。