如何从zip文件中读取数据而不必解压缩整个文件

Question

无论如何在.Net(C#)中从zip文件中提取数据而不解压缩整个文件？

简单地说,我可能想从zip文件的开头提取数据(文件),显然这取决于压缩算法是否以确定的顺序压缩文件.

Answer 1

使用.Net Framework 4.5(使用ZipArchive):

using (ZipArchive zip = ZipFile.Open(zipfile, ZipArchiveMode.Read))
    foreach (ZipArchiveEntry entry in zip.Entries)
        if(entry.Name == "myfile")
            entry.ExtractToFile("myfile");

在zipfile中找到"myfile"并将其解压缩.

Answer 2

DotNetZip是你的朋友.

一样容易:

using (ZipFile zip = ZipFile.Read(ExistingZipFile))
{
  ZipEntry e = zip["MyReport.doc"];
  e.Extract(OutputStream);
}

(您也可以提取到文件或其他目的地).

阅读zip文件的目录非常简单:

using (ZipFile zip = ZipFile.Read(ExistingZipFile))
{
  foreach (ZipEntry e in zip)
  {
    if (header)
    {
      System.Console.WriteLine("Zipfile: {0}", zip.Name);
      if ((zip.Comment != null) && (zip.Comment != "")) 
        System.Console.WriteLine("Comment: {0}", zip.Comment);
      System.Console.WriteLine("\n{1,-22} {2,8}  {3,5}   {4,8}  {5,3} {0}",
                               "Filename", "Modified", "Size", "Ratio", "Packed", "pw?");
      System.Console.WriteLine(new System.String('-', 72));
      header = false;
    }
    System.Console.WriteLine("{1,-22} {2,8} {3,5:F0}%   {4,8}  {5,3} {0}",
                             e.FileName,
                             e.LastModified.ToString("yyyy-MM-dd HH:mm:ss"),
                             e.UncompressedSize,
                             e.CompressionRatio,
                             e.CompressedSize,
                             (e.UsesEncryption) ? "Y" : "N");

  }
}

编辑注: DotNetZip曾经住在Codeplex.Codeplex已关闭.Codeplex仍然可以使用旧存档.看起来代码已迁移到Github:

• https://github.com/DinoChiesa/DotNetZip.看起来是原作者的回购.
• https://github.com/haf/DotNetZip.Semverd.这看起来是当前维护的版本.它也可以通过Nuget打包,网址为https://www.nuget.org/packages/DotNetZip/

Answer 3

如果你想使用SharpZipLib,这样的东西将逐个列出并提取文件:

var zip = new ZipInputStream(File.OpenRead(@"C:\Users\Javi\Desktop\myzip.zip"));
var filestream = new FileStream(@"C:\Users\Javi\Desktop\myzip.zip", FileMode.Open, FileAccess.Read);
ZipFile zipfile = new ZipFile(filestream);
ZipEntry item;
while ((item = zip.GetNextEntry()) != null)
{
     Console.WriteLine(item.Name);
     using (StreamReader s = new StreamReader(zipfile.GetInputStream(item)))
     {
      // stream with the file
          Console.WriteLine(s.ReadToEnd());
     }
 }

基于此示例:zip文件中的内容

Answer 4

以下是如何从zip存档中将UTF8文本文件读取到字符串变量（.NET Framework 4.5及更高版本）中的方法：

string zipFileFullPath = "{{TypeYourZipFileFullPathHere}}";
string targetFileName = "{{TypeYourTargetFileNameHere}}";
string text = new string(
            (new System.IO.StreamReader(
             System.IO.Compression.ZipFile.OpenRead(zipFileFullPath)
             .Entries.Where(x => x.Name.Equals(targetFileName,
                                          StringComparison.InvariantCulture))
             .FirstOrDefault()
             .Open(), Encoding.UTF8)
             .ReadToEnd())
             .ToArray());