Asp.net 断点续传 下载大文件
/// <summary>
/// 支持断点续传的下载大文件的函数
/// </summary>
/// <param name="downloadFilePath">被下载文件的路径,相对和绝对都可以</param>
/// <param name="showFileName">显示给用户的文件名,可以为空</param>
/// <param name="fileType">要下载的文件类型,如果不确定,请留空</param>
/// <remarks>用于大文件的下载</remarks>
public static void BigFileDownload(string downloadFilePath, string showFileName, string fileType)
{
downloadFilePath = downloadFilePath.Trim();
if(string.Empty == downloadFilePath)
ShowErrorMessage("没有指定要下载的文件路径!");
if(downloadFilePath.IndexOf(":") < 0)
downloadFilePath = System.Web.HttpContext.Current.Server.MapPath(downloadFilePath);
showFileName = showFileName.Trim();
if(string.Empty == showFileName)
showFileName = Path.GetFileName(downloadFilePath);
showFileName = System.Web.HttpUtility.UrlEncode(System.Web.HttpContext.Current.Request.ContentEncoding.GetBytes(showFileName));
fileType = fileType.Trim();
if(string.Empty == fileType)
fileType = "application/octet-stream";
System.Web.HttpContext.Current.Response.Clear();
Stream objStream = null;
byte[] btBuffer = new byte[8192]; // 1024*8 = 8Kb
int intLength = 0;
long lngData2Read = 0;
try
{
using(objStream = new FileStream(downloadFilePath, FileMode.Open, FileAccess.Read, FileShare.Read))
{
lngData2Read = objStream.Length;
输出HTTP头信息
while(lngData2Read > 0)
{
if(HttpContext.Current.Response.IsClientConnected)
{
intLength = objStream.Read(btBuffer, 0, 8192);
HttpContext.Current.Response.OutputStream.Write(btBuffer, 0, intLength);
HttpContext.Current.Response.Flush();
lngData2Read -= intLength;
btBuffer = new byte[8192];
}
else
{
lngData2Read = -1;
}
}
}
}
catch(Exception ex)
{
ShowErrorMessage(ex.Message);
}
// 结束文件下载,此句不可缺少,否则会把本页的HTML代码一起下载文件里
HttpContext.Current.Response.End();
}
/// <summary>
/// 输出错误信息给用户,采用客户端弹出框的方式
/// </summary>
/// <param name="errorMessage">错误信息的内容</param>
internal static void ShowErrorMessage(string errorMessage)
{
errorMessage = errorMessage.Replace("'", "\"");
System.Web.HttpContext.Current.Response.Write("<script language='javascript'>");
System.Web.HttpContext.Current.Response.Write("alert('");
System.Web.HttpContext.Current.Response.Write(errorMessage);
System.Web.HttpContext.Current.Response.Write("');</script>");
System.Web.HttpContext.Current.Response.End();
}
/// 支持断点续传的下载大文件的函数
/// </summary>
/// <param name="downloadFilePath">被下载文件的路径,相对和绝对都可以</param>
/// <param name="showFileName">显示给用户的文件名,可以为空</param>
/// <param name="fileType">要下载的文件类型,如果不确定,请留空</param>
/// <remarks>用于大文件的下载</remarks>
public static void BigFileDownload(string downloadFilePath, string showFileName, string fileType)
{
downloadFilePath = downloadFilePath.Trim();
if(string.Empty == downloadFilePath)
ShowErrorMessage("没有指定要下载的文件路径!");
if(downloadFilePath.IndexOf(":") < 0)
downloadFilePath = System.Web.HttpContext.Current.Server.MapPath(downloadFilePath);
showFileName = showFileName.Trim();
if(string.Empty == showFileName)
showFileName = Path.GetFileName(downloadFilePath);
showFileName = System.Web.HttpUtility.UrlEncode(System.Web.HttpContext.Current.Request.ContentEncoding.GetBytes(showFileName));
fileType = fileType.Trim();
if(string.Empty == fileType)
fileType = "application/octet-stream";
System.Web.HttpContext.Current.Response.Clear();
Stream objStream = null;
byte[] btBuffer = new byte[8192]; // 1024*8 = 8Kb
int intLength = 0;
long lngData2Read = 0;
try
{
using(objStream = new FileStream(downloadFilePath, FileMode.Open, FileAccess.Read, FileShare.Read))
{
lngData2Read = objStream.Length;
输出HTTP头信息
while(lngData2Read > 0)
{
if(HttpContext.Current.Response.IsClientConnected)
{
intLength = objStream.Read(btBuffer, 0, 8192);
HttpContext.Current.Response.OutputStream.Write(btBuffer, 0, intLength);
HttpContext.Current.Response.Flush();
lngData2Read -= intLength;
btBuffer = new byte[8192];
}
else
{
lngData2Read = -1;
}
}
}
}
catch(Exception ex)
{
ShowErrorMessage(ex.Message);
}
// 结束文件下载,此句不可缺少,否则会把本页的HTML代码一起下载文件里
HttpContext.Current.Response.End();
}
/// <summary>
/// 输出错误信息给用户,采用客户端弹出框的方式
/// </summary>
/// <param name="errorMessage">错误信息的内容</param>
internal static void ShowErrorMessage(string errorMessage)
{
errorMessage = errorMessage.Replace("'", "\"");
System.Web.HttpContext.Current.Response.Write("<script language='javascript'>");
System.Web.HttpContext.Current.Response.Write("alert('");
System.Web.HttpContext.Current.Response.Write(errorMessage);
System.Web.HttpContext.Current.Response.Write("');</script>");
System.Web.HttpContext.Current.Response.End();
}
作者: 三角猫
http://www.zu14.cn/
转载请保留此信息