物理路径，虚拟路径，物理路径与虚拟路径转换，文件下载方法

1 什么是物理路径？什么是虚拟路径？
(1) 例子：
用IIS举个例子：
WEB服务目录是d:\路径
那么用HTTP访问网站根目录的时候，其实访问的是d:\路径,那么其中虚拟路径就是\（根），物理路径就是d:\路径

(2) 我自己的理解：绝对路径一般都是带有磁盘完成路径， 而虚拟路径一般不带有磁盘

2 程序中虚拟路径和物理路径的转化

#region 物理路径和相对路径的转换
//本地路径转换成URL相对路径
private string urlconvertor(string imagesurl1)
{
string tmpRootDir = Server.MapPath(System.Web.HttpContext.Current.Request.ApplicationPath.ToString());//获取程序根目录
string imagesurl2 = imagesurl1.Replace(tmpRootDir, ""); //转换成相对路径
imagesurl2 = imagesurl2.Replace(@"\", @"/");
//imagesurl2 = imagesurl2.Replace(@"Aspx_Uc/", @"");
return imagesurl2;
}
//相对路径转换成服务器本地物理路径
private string urlconvertorlocal(string imagesurl1)
{
string tmpRootDir = Server.MapPath(System.Web.HttpContext.Current.Request.ApplicationPath.ToString());//获取程序根目录
string imagesurl2 = tmpRootDir + imagesurl1.Replace(@"/", @"\"); //转换成绝对路径
return imagesurl2;
}
#endregion

3 下载的方法

/// <summary>
/// 获取物理地址
/// </summary>
public static string MapPathFile(string FileName)
{
return HttpContext.Current.Server.MapPath(FileName);
}
/// <summary>
/// 普通下载
/// </summary>
/// <param name="FileName">文件虚拟路径</param>
public static bool DownLoadold(string FileName)
{
bool bools = false;
string destFileName = MapPathFile(FileName);
if (File.Exists(destFileName))
{
FileInfo fi = new FileInfo(destFileName);
HttpContext.Current.Response.Clear();
HttpContext.Current.Response.ClearHeaders();
HttpContext.Current.Response.Buffer = false;
HttpContext.Current.Response.AppendHeader("Content-Disposition", "attachment;filename=" + HttpUtility.UrlEncode(Path.GetFileName(destFileName), System.Text.Encoding.UTF8));
HttpContext.Current.Response.AppendHeader("Content-Length", fi.Length.ToString());
HttpContext.Current.Response.ContentType = "application/octet-stream";
HttpContext.Current.Response.WriteFile(destFileName);
HttpContext.Current.Response.Flush();
HttpContext.Current.Response.End();
bools = true;
}
return bools;
}

public static void ResponseFile(string path, HttpContext context)
{
context = HttpContext.Current;

System.IO.Stream iStream = null;
byte[] buffer = new Byte[10000];
int length;
long dataToRead;
string filename = System.IO.Path.GetFileName(path);

try
{
iStream = new System.IO.FileStream(path, System.IO.FileMode.Open, System.IO.FileAccess.Read, System.IO.FileShare.Read);
dataToRead = iStream.Length;
context.Response.ContentType = "application/octet-stream";
context.Response.AddHeader("Content-Disposition", "attachment; filename=" + HttpUtility.UrlEncode(filename, System.Text.Encoding.UTF8));

while (dataToRead > 0)
{
if (context.Response.IsClientConnected)
{
length = iStream.Read(buffer, 0, 10000);
context.Response.OutputStream.Write(buffer, 0, length);
context.Response.Flush();

buffer = new Byte[10000];
dataToRead = dataToRead - length;
}
else
{
dataToRead = -1;
}
}
}
catch (Exception ex)
{
context.Response.Write(ex.Message);
}
finally
{
if (iStream != null)
{
iStream.Close();
}
}
}

public static void ResponseFile(string path, string fileName, HttpContext context)
{
context = HttpContext.Current;

System.IO.Stream iStream = null;
byte[] buffer = new Byte[10000];
int length;
long dataToRead;

try
{
iStream = new System.IO.FileStream(path, System.IO.FileMode.Open, System.IO.FileAccess.Read, System.IO.FileShare.Read);
dataToRead = iStream.Length;
context.Response.ContentType = "application/octet-stream";
context.Response.AddHeader("Content-Disposition", "attachment; filename=" + HttpUtility.UrlEncode(fileName, System.Text.Encoding.UTF8));

while (dataToRead > 0)
{
if (context.Response.IsClientConnected)
{
length = iStream.Read(buffer, 0, 10000);
context.Response.OutputStream.Write(buffer, 0, length);
context.Response.Flush();

buffer = new Byte[10000];
dataToRead = dataToRead - length;
}
else
{
dataToRead = -1;
}
}
}
catch (Exception ex)
{
context.Response.Write(ex.Message);
}
finally
{
if (iStream != null)
{
iStream.Close();
}
}
}