public void VirDownload(List <E_SourceFile> sourceList)
{
fileList = sourceList;
//文件个数以及大小校验
if (fileList.Count == 0)
{
ExitError("文件不存在"); return;
}
if (fileList.Sum(s => (long)s.FileSize) > int.MaxValue)
{
ExitError("文件过大,请减少文件个数后下载"); return;
}
try
{
ProcessSoftList();
//根据资料集合构建
E_VirtualZipStruct zipStruct = BuildZipStruct();
//发送文件
SendFile(zipStruct);
}
catch (OutOfMemoryException)
{
float a = GetFreeMemory(0);
Util.SaveLog(_config.LogPath, $"当前内存不足,剩余内存为:{GetFreeMemory()}MB(排除了保留内存{_config.ReseverMemory / 1024 / 1024}GB)");
ExitError("服务器忙...请稍后再试"); return;
}
catch (Exception ex)
{
Util.SaveLog(_config.LogPath, ex.StackTrace.ToString());
ExitError("服务器异常,请稍后重试"); return;
}
}
/// <summary>
/// 发送文件
/// </summary>
/// <param name="zipStruct">Zip结构</param>
private void SendFile(E_VirtualZipStruct zipStruct)
{
//设定默认字节流
uint DefaultBuffer = 256 * 1024;
//已经读取的文件流长度
uint readOffset = 0;
//缓冲区位移,用于判断是否该写入
uint bfrOffset = 0;
string saveFileName = string.Format("打包下载{0}等{1}个文件.zip", fileList[0].FileName, fileList.Count);
context.Response.ContentType = "application/octet-stream";
context.Response.AddHeader("Content-Disposition", "attachement;filename=" + HttpUtility.UrlEncode(saveFileName));
context.Response.AddHeader("Content-Length", zipStruct.ZipFileSize.ToString());
context.Response.AddHeader("Connection", "Keep-Alive");
//重置写入文件的Buffer大小(用于重置小于1M的文件大小)
byte[] bfrByte = ResetBuffer(ref readOffset, zipStruct.ZipFileSize, DefaultBuffer);
#region 文件读取
//1.读取zipXml中的data区域
foreach (var item in zipStruct.Header)
{
//1-1.读取头部区域的头部字节部分
{
//读取配置中的头部字节
byte[] headerByte = item.Item1;
//定义头部字节读取时的偏移量
ReadAndWrite(zipStruct.ZipFileSize, DefaultBuffer, ref readOffset, ref bfrOffset, ref bfrByte, headerByte);
}
//1-2.读取头部区域的文件流
{
string path = item.Item2;
ReadAndWrite(zipStruct.ZipFileSize, DefaultBuffer, ref readOffset, ref bfrOffset, ref bfrByte, path);
}
}
//2.读取zipXML中的DIR区域
{
byte[] DirByte = zipStruct.Dir.ToArray();
ReadAndWrite(zipStruct.ZipFileSize, DefaultBuffer, ref readOffset, ref bfrOffset, ref bfrByte, DirByte);
}
//3.读取zipXML中的End区域
{
byte[] EndByte = zipStruct.End.ToArray();
ReadAndWrite(zipStruct.ZipFileSize, DefaultBuffer, ref readOffset, ref bfrOffset, ref bfrByte, EndByte);
}
context.Response.Close();
context.Response.End();
#endregion
}
/// <summary>
/// 构建Zip结构
/// </summary>
/// <returns></returns>
private E_VirtualZipStruct BuildZipStruct()
{
E_VirtualZipStruct zipStruct = new E_VirtualZipStruct();
//定义头部和目录的集合(用于计算目录偏移量)
List <E_FileAndDir> fdList = new List <E_FileAndDir>();
//合计文件大小
long totalFileSize = 0;
//虚拟压缩包总大小(包含文件大小和头部,目录,尾部区域的字节)
long virtualZipSize = 0;
foreach (var file in fileList)
{
//1.构造头部区域
E_LocalFileHeader header = FileHeaderInstance(file);
zipStruct.Header.Add(new Tuple <byte[], string>(header.GetAllBytes(), file.PhyFilePath));
virtualZipSize += header.GetAllBytes().Count();
//2.构造目录部分
E_CentralDirFileHeader dir = CentralDirInstance(file);
//计算dir的偏移量
if (fdList.Count > 0)
{
dir.HeaderOffset = GetClassSize(fdList.Select(s => s.Header).ToList(), (int)totalFileSize);
}
zipStruct.Dir.AddRange(dir.GetAllBytes());
//向头部和目录集合添加记录
fdList.Add(new E_FileAndDir()
{
Header = header,
Dir = dir
});
totalFileSize += file.FileSize;
}
E_EndCentralDirRecord endDir = EndDirInstance(fdList, (int)totalFileSize);
zipStruct.End.AddRange(endDir.GetAllBytes());
virtualZipSize += zipStruct.Dir.Count();
virtualZipSize += zipStruct.End.Count();
virtualZipSize += totalFileSize;
zipStruct.ZipFileSize = (uint)virtualZipSize;
return(zipStruct);
}
public void VirDownload(IList <E_SourceFile> sourceList)
{
fileList = sourceList;
//文件个数以及大小校验
if (fileList.Count == 0)
{
ExitError("文件不存在"); return;
}
if (fileList.Sum(s => (long)s.FileSize) > int.MaxValue)
{
ExitError("文件过大,请减少文件个数后下载"); return;
}
//处理资料文件地址,文件名等
try
{
ProcessSoftList();
}
catch (OutOfMemoryException)
{
float a = GetFreeMemory(0);
ExitError("服务器忙...请稍后再试"); return;
}
catch (Exception ex)
{
try
{
Util.SaveLog(_config.ErrorLogSavePath, ex.StackTrace.ToString());
}
catch { }
ExitError("服务器异常,请稍后重试"); return;
}
//根据资料集合构建
E_VirtualZipStruct zipStruct = BuildZipStruct();
//发送文件
SendFile(zipStruct);
}
