/// <summary>
/// 开始下载
/// </summary>
/// <param name="url">下载url</param>
/// <param name="fileName">保存文件名</param>
public void download(string url, string fileName)
{
if (mCurDownloadSta == eDownloadSta.STA_ING)
{
Console.WriteLine("url:{0} is downloading...", url);
return;
}
if (mHttpUrl != url)//新的下载文件要重新计数
{
init();
}
else
{
FullSize = 0.0;
DownloadedSize = 0.0;
LengthInOneSecond = 0.0;
RemainTime = 0;
}
mHttpUrl = url;
mSaveFileName = fileName;
if (fileName.Length < 1)
{
mSaveFileName = Directory.GetCurrentDirectory() + Path.GetFileName(url);
}
mCurDownloadSta = eDownloadSta.STA_START;
//Task.Run(() =>
//{
//});
mTimer.Start();
mCurDownloadSta = eDownloadSta.STA_ING;
Console.WriteLine("start download:");
int ret = -1;
try
{
ret = dowLoadFile();
}
catch (Exception e)
{
ret = -100;
Console.WriteLine("dowload err, err:" + e.Message);
ErrorHappend?.Invoke(this, new UnhandledExceptionEventArgs(e, false));
}
mCurDownloadSta = eDownloadSta.STA_FINISH;
mTimer.Stop();
if (ret < 0)
{
Progress?.Invoke(this, new DownloadProgressEventArgs(FullSize, FullSize, 0, 0, eDownloadSta.STA_ERR));
}
else if (ret == 0)
{
Progress?.Invoke(this, new DownloadProgressEventArgs(FullSize, FullSize, 0, 0, eDownloadSta.STA_FINISH));
}
else
{
Progress?.Invoke(this, new DownloadProgressEventArgs(DownloadedSize, Speed, RemainTime, TotalTime, eDownloadSta.STA_FINISH));
}
}
/// <summary>
/// 下载文件（同步） 支持断点续传
/// </summary>
public int dowLoadFile()
{
int errCnt = 0;
//打开上次下载的文件或新建文件
long startPos = 0;
FileStream fs = null;
if (File.Exists(mSaveFileName))//文件已经存在就继续下载
{
try
{
fs = File.OpenWrite(mSaveFileName);
if (null == fs)
{
Console.WriteLine("open file failed:" + mSaveFileName);
return(-1);
}
startPos = fs.Length;
}
catch (Exception e)
{
Console.WriteLine("open file err:" + e.Message);
ErrorHappend?.Invoke(this, new UnhandledExceptionEventArgs(e, false));
if (null != fs)
{
fs.Close();
return(-2);
}
}
}
else//新文件
{
fs = new FileStream(mSaveFileName, FileMode.Create);
Console.WriteLine("创建文件");
startPos = 0;
}
/**获取文件大小**/
HttpWebRequest request = (HttpWebRequest)WebRequest.Create(mHttpUrl);
if (null == request)
{
return(-3);
}
request.UserAgent = "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/68.0.3440.106 Safari/537.36";
//request.KeepAlive = true;//保持连接
//设置Range值，请求指定位置开始的数据,实现断点续传
request.AddRange(startPos);//request.AddRange(startPos, endPos)获取指定范围数据，续传跟重传(中间某部分)可使用该函数
WebResponse respone = null;
//注:断点续传必须在request后、并设置AddRange后第一次获取的Response才是正确的数据流
try
{
respone = request.GetResponse();
if (null == respone)
{
request.Abort();
fs.Close();
return(-4);
}
}
catch (Exception e)
{
Console.WriteLine("getResponse err:" + e.Message);
ErrorHappend?.Invoke(this, new UnhandledExceptionEventArgs(e, false));
fs.Close();
return(-4);
}
FullSize = Convert.ToDouble(respone.ContentLength) + startPos;
//发送文件大小
if (FullSize < 0)
{
Console.WriteLine("获取文件大小失败");
return(-5);
}
//文件错误，清空文件
if (FullSize < startPos)
{
fs.SetLength(0);//截断文件，相当于是清空文件内容
Console.WriteLine("文件错误，清空后重新下载");
}
DownloadedSize = startPos;
//文件已下载
if (DownloadedSize >= FullSize)
{
fs.Close();
respone.Close();
request.Abort();
//Finished?.Invoke(this, new EventArgs());
Console.WriteLine("文件已经下载");
return(0);
}
fs.Seek(startPos, SeekOrigin.Begin); //移动文件流中的当前指针
//Console.WriteLine("startPos:{0}", startPos);
Stream responseStream = null;
byte[] dataBuf = new byte[BUF_SIZE];
//打开网络连接
try
{
//向服务器请求，获得服务器回应数据流
responseStream = respone.GetResponseStream();
if (null == responseStream)
{
fs.Close();
respone.Close();
request.Abort();
return(-6);
}
int nReadSize = 0;
do
{
//读取数据
nReadSize = responseStream.Read(dataBuf, 0, BUF_SIZE);
if (nReadSize > 0)
{
fs.Write(dataBuf, 0, nReadSize);
//此处应该判断是否写入成功
//已下载大小
DownloadedSize += nReadSize;
LengthInOneSecond += nReadSize;
}
else
{
errCnt++;
if (errCnt > READ_ERR_MAX_CNT)
{
Console.WriteLine("下载出错，退出下载");
break;
}
}
if (mCurDownloadSta == eDownloadSta.STA_STOP)
{
Console.WriteLine("停止下载");
break;
}
} while (DownloadedSize < FullSize);
responseStream.Close();
respone.Close();
fs.Close();
request.Abort();
//Console.WriteLine("DownloadedSize:{0}, FullSize:{1}", DownloadedSize, FullSize);
if (DownloadedSize == FullSize)//下载完成
{
Console.WriteLine("下载完成");
//Finished?.Invoke(this, new EventArgs());
return(100);
}
return(1);
}
catch (Exception ex)//下载失败
{
responseStream.Close();
respone.Close();
fs.Close();
request.Abort();
Console.WriteLine("下载失败:" + ex.ToString());
return(-7);
}
}