OutOfMemoryException当发送大文件500MB使用FileStream ASPNET [英] OutOfMemoryException when send big file 500MB using FileStream ASPNET
问题描述
我使用Filestream读取大文件（> 500 MB），并获得OutOfMemoryException。
我使用Asp.net，.net 3.5，win2003，iis 6.0
我想在我的应用程序：
从Oracle中读取数据
使用FileStream和BZip2解压文件
读取文件未压缩，并发送到asp.net页面进行下载。
当我从磁盘读取文件时，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）
{
//如果我们被传递了一个无效的初始长度，只需
//使用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;
//如果我们已经到达缓冲区的末尾，检查是否有
//任何更多的信息
if（read == buffer.Length）
{
int nextByte = stream.ReadByte（）;
//结束流？如果是这样，我们完成
if（nextByte == -1）
{
return buffer;
}
//不，调整缓冲区大小，放入我们刚刚
//读取的字节，然后继续
byte [] newBuffer = new byte [buffer.Length * 2];
Array.Copy（buffer，newBuffer，buffer.Length）;
newBuffer [read] =（byte）nextByte;
buffer = newBuffer;
read ++;
}
}
//缓冲区现在太大了。收缩它
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。
问题是如下：
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）进行下载。
使用
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，如何发送一个大文件到ASPNET响应流？
我发现这个代码由Cheeso：
使用（var fs = new FileStream（filePath，FileMode.Open，FileAccess.Read））
{
Response.BufferOutput = false;
//以防止缓冲
byte [] buffer = new byte [1024];
int bytesRead = 0;
while（（bytesRead = fs.Read（buffer，0，buffer.Length））> 0）
{
Response.OutputStream.Write（buffer，0，bytesRead）;
}
}
是不是很好的代码？任何对高性能的改进？
一个collegue说我，使用
Response.TransmitFile（文件路径）;
现在，另一个问题，更好的TransmitFile或Cheeso代码？
许多年以前，在msdn杂志上看到很好的文章，但是我无法访问 http://msdn.microsoft.com/msdnmag/issues/06/09/WebDownloads/ ，
更新：您可以使用链接中的 webarchive 访问： https://web.archive.org/web/20070627063111/http://msdn.microsoft.com/msdnmag/issues/06/09/ WebDownloads /
任何建议，评论，示例代码来源??
我创建了下载页面，允许用户在几个月前下载最多4gb（可能更多）。这是我的工作片段：
private void TransmitFile（string fullPath，string outFileName）
{
系统.IO.Stream iStream = null;
//块读取10K字节的缓冲区：
byte [] buffer = new Byte [10000];
//文件长度：
int length;
//要读取的字节总数：
long dataToRead;
//识别要下载的文件，包括其路径。
string filepath = fullPath;
//识别文件名。
string filename = System.IO.Path.GetFileName（filepath）;
try
{
//打开文件。
iStream = new System.IO.FileStream（filepath，System.IO.FileMode.Open，
System.IO.FileAccess.Read，System.IO.FileShare.Read）;
//要读取的字节总数：
dataToRead = iStream.Length;
Response.Clear（）;
Response.ContentType =application / octet-stream;
Response.AddHeader（Content-Disposition，attachment; filename =+ outFileName）;
Response.AddHeader（Content-Length，iStream.Length.ToString（））;
//读取字节。
while（dataToRead> 0）
{
//验证客户端是否连接。
if（Response.IsClientConnected）
{
//读取缓冲区中的数据。
length = iStream.Read（buffer，0，10000）;
//将数据写入当前输出流。
Response.OutputStream.Write（buffer，0，length）;
//将数据刷新到输出。
Response.Flush（）;
buffer = new Byte [10000];
dataToRead = dataToRead - length;
}
else
{
//防止无限循环，如果用户断开
dataToRead = -1;
}
}
}
catch（Exception ex）
{
抛出新的ApplicationException（ex.Message）;
}
finally
{
if（iStream！= null）
{
//关闭文件。
iStream.Close（）;
}
Response.Close（）;
}
}
I'm using Filestream for read big file (> 500 MB) and I get the OutOfMemoryException.
I use Asp.net , .net 3.5, win2003, iis 6.0
I want this in my app:
Read DATA from Oracle
Uncompress file using FileStream and BZip2
Read file uncompressed and send it to asp.net page for download.
When I read file from disk, Fails !!! and get OutOfMemory...
. My Code is:
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;
}
Now, I specify my issue better.
Uncompress file using FileStream and BZip2 is OK, all is right.
The Problem is the following:
Read fat big file in disk (> 500 MB) in byte[] and send bytes to Response (asp.net) for download it.
When use
http://www.yoda.arachsys.com/csharp/readbinary.html
public static byte[] ReadFully
I get the error: OutOfMemoryException...
If better BufferedStream than Stream (FileStream, MemoryStream, ...) ??
Using BufferedStream , Can I read big file of 700 MB ?? (any sample code source using BufferedStream for download big file)
I think, this is the question: Not "how to read a 500mb file into memory?" , But "how to send a large file to the ASPNET Response stream?"
I found this code by Cheeso:
using (var fs = new FileStream(filePath, FileMode.Open, FileAccess.Read))
{
Response.BufferOutput= false; // to prevent buffering
byte[] buffer = new byte[1024];
int bytesRead = 0;
while ((bytesRead = fs.Read(buffer, 0, buffer.Length)) > 0)
{
Response.OutputStream.Write(buffer, 0, bytesRead);
}
}
Is it good code ?? any improvements for high performance ??
A collegue say me, use
Response.TransmitFile(filePath);
Now, another question, better TransmitFile or code by Cheeso ??
Many years ago, in msdn magazine appears great article about it but I cannot access http://msdn.microsoft.com/msdnmag/issues/06/09/WebDownloads/,
Update: You can access using webarchive in the link: https://web.archive.org/web/20070627063111/http://msdn.microsoft.com/msdnmag/issues/06/09/WebDownloads/
Any suggestions, comments, sample code source??
I've created download page which allows user to download up to 4gb (may be more) few months ago. Here is my working snippet:
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, 0, 10000);
// Write the data to the current output stream.
Response.OutputStream.Write(buffer, 0, 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();
}
}
这篇关于OutOfMemoryException当发送大文件500MB使用FileStream ASPNET的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！
