我使用Asp.net,.net 3.5,win2003,iis 6.0
我想在我的应用程序中：
从Oracle读取DATA
使用FileStream和BZip2解压缩文件
当我从磁盘读取文件,失败!!!并获得OutOfMemory …
.我的代码是：
using (var fs3 = new FileStream(filePath2,FileMode.Open,FileAccess.Read))
{
byte[] b2 = ReadFully(fs3,1024);
}
// http://www.yoda.arachsys.com/csharp/readbinary.html
public static byte[] ReadFully(Stream stream,int initialLength)
{
// If we've been passed an unhelpful initial length,just
// use 32K.
if (initialLength < 1)
{
initialLength = 32768;
}
byte[] buffer = new byte[initialLength];
int read = 0;
int chunk;
while ((chunk = stream.Read(buffer,read,buffer.Length - read)) > 0)
{
read += chunk;
// If we've reached the end of our buffer,check to see if there's
// any more information
if (read == buffer.Length)
{
int nextByte = stream.ReadByte();
// End of stream? If so,we're done
if (nextByte == -1)
{
return buffer;
}
// Nope. Resize the buffer,put in the byte we've just
// read,and continue
byte[] newBuffer = new byte[buffer.Length * 2];
Array.Copy(buffer,newBuffer,buffer.Length);
newBuffer[read] = (byte)nextByte;
buffer = newBuffer;
read++;
}
}
// Buffer is now too big. Shrink it.
byte[] ret = new byte[read];
Array.Copy(buffer,ret,read);
return ret;
}
现在,我更好地指定了我的问题.
使用FileStream和BZip2解压缩文件可以,一切正常.
问题如下：
在字节[]中读取磁盘中的胖大文件(> 500 MB),并将字节发送到Response(asp.net)以进行下载.
使用时
http://www.yoda.arachsys.com/csharp/readbinary.html
public static byte[] ReadFully
我收到错误：OutOfMemoryException …
如果比Stream更好的BufferedStream(FileStream,MemoryStream,…)？
使用BufferedStream,可以读取700 MB的大文件吗？ (任何示例代码源使用BufferedStream下载大文件)
我想,这是一个问题：不是“如何读取500mb文件到内存？”但是“如何发送大文件到ASPNET响应流？”
我发现这个代码由Cheeso：
using (var fs = new FileStream(filePath,FileAccess.Read))
{
Response.BufferOutput= false; // to prevent buffering
byte[] buffer = new byte[1024];
int bytesRead = 0;
while ((bytesRead = fs.Read(buffer,buffer.Length)) > 0)
{
Response.OutputStream.Write(buffer,bytesRead);
}
}
一个同事说我,使用
Response.TransmitFile(filePath);
现在,另一个问题,更好的TransmitFile或代码由Cheeso？
很多年前,在msdn杂志上出现很好的文章,但是我无法访问http://msdn.microsoft.com/msdnmag/issues/06/09/WebDownloads/,
更新：您可以使用webarchive访问链接：https://web.archive.org/web/20070627063111/http://msdn.microsoft.com/msdnmag/issues/06/09/WebDownloads/
任何建议,意见,示例代码来源？
解决方法
private void TransmitFile(string fullPath,string outFileName)
{
System.IO.Stream iStream = null;
// Buffer to read 10K bytes in chunk:
byte[] buffer = new Byte[10000];
// Length of the file:
int length;
// Total bytes to read:
long dataToRead;
// Identify the file to download including its path.
string filepath = fullPath;
// Identify the file name.
string filename = System.IO.Path.GetFileName(filepath);
try
{
// Open the file.
iStream = new System.IO.FileStream(filepath,System.IO.FileMode.Open,System.IO.FileAccess.Read,System.IO.FileShare.Read);
// Total bytes to read:
dataToRead = iStream.Length;
Response.Clear();
Response.ContentType = "application/octet-stream";
Response.AddHeader("Content-Disposition","attachment; filename=" + outFileName);
Response.AddHeader("Content-Length",iStream.Length.ToString());
// Read the bytes.
while (dataToRead > 0)
{
// Verify that the client is connected.
if (Response.IsClientConnected)
{
// Read the data in buffer.
length = iStream.Read(buffer,10000);
// Write the data to the current output stream.
Response.OutputStream.Write(buffer,length);
// Flush the data to the output.
Response.Flush();
buffer = new Byte[10000];
dataToRead = dataToRead - length;
}
else
{
//prevent infinite loop if user disconnects
dataToRead = -1;
}
}
}
catch (Exception ex)
{
throw new ApplicationException(ex.Message);
}
finally
{
if (iStream != null)
{
//Close the file.
iStream.Close();
}
Response.Close();
}
}
