四、Bug——WebClient、HttpWebRequest等方法下载远程url文件总是中断,抛出异常

抛出异常的原因是http协议默认的并发访问量是2,但是当长时间访问网络不好,或者数据量较大的路径时候就会很快消耗完访问次数,所以解决办法如下(另外附上一个简单的下载方法,网上多的是):、
 System.Net.ServicePointManager.DefaultConnectionLimit = 999;(999这个数字是随便写的,一般情况下512就够了,最大建议不要超过1024)
///
///下载方法
///serverPath为网络要下载的路径
public static void Download(string serverPath) {   WebClient client = new WebClient();   HttpWebRequest myRequest = null;   string fileName = "概预算表.xls";//被下载的文件名   serverPath= "另存为路径" + fileName;//另存为地址   FileStream writeStream = new FileStream(path, FileMode.Append, FileAccess.Write, FileShare.ReadWrite);   try   {     myRequest = (HttpWebRequest)HttpWebRequest.Create(serverPath);//url地址 http://******     System.Net.ServicePointManager.DefaultConnectionLimit = 999;/*---------这里最重要--------*/     Stream readStream = myRequest.GetResponse().GetResponseStream();     byte[] btArray = new byte[512];     int contentSize = readStream.Read(btArray, 0, btArray.Length);     while (contentSize > 0)     {       writeStream.Write(btArray, 0, contentSize);       contentSize = readStream.Read(btArray, 0, btArray.Length);     }     //GC.Collect();     GC.WaitForPendingFinalizers();     //关闭流     writeStream.Close();     readStream.Close();   }   catch (Exception ex)   {     writeStream.Close();     System.Windows.Forms.MessageBox.Show(ex.Message, "提示");   } }

 

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