欢迎您访问程序员文章站本站旨在为大家提供分享程序员计算机编程知识!
您现在的位置是: 首页  >  IT编程

asp.NET中实现文件的压缩和解压(3种方式)

程序员文章站 2023-11-18 16:53:28
在.net可以通过多种方式实现zip的压缩和解压:1、使用system.io.packaging;2、使用第三方类库;3、通过 system.io.compression...

在.net可以通过多种方式实现zip的压缩和解压:1、使用system.io.packaging;2、使用第三方类库;3、通过 system.io.compression 命名空间中新增的ziparchive、zipfile等类实现。

一、使用system.io.packaging压缩和解压

package为一个抽象类,可用于将对象组织到定义的物理格式的单个实体中,从而实现可移植性与高效访问。zip 文件是package的主物理格式。 其他package实现可以使用其他物理格式(如 xml 文档、数据库或 web 服务。与文件系统类似,在分层组织的文件夹和文件中引用 package 中包含的项。虽然 package 是抽象类,但 package.open 方法默认使用 zippackage 派生类。

system.io.packaging在windowsbase.dll程序集下,使用时需要添加对windowsbase的引用。

 1、将整个文件夹压缩成zip

 /// <summary>
  /// add a folder along with its subfolders to a package
  /// </summary>
  /// <param name="foldername">the folder to add</param>
  /// <param name="compressedfilename">the package to create</param>
  /// <param name="overrideexisting">override exsisitng files</param>
  /// <returns></returns>
  static bool packagefolder(string foldername, string compressedfilename, bool overrideexisting)
  {
   if (foldername.endswith(@"\"))
    foldername = foldername.remove(foldername.length - 1);
   bool result = false;
   if (!directory.exists(foldername))
   {
    return result;
   }

   if (!overrideexisting && file.exists(compressedfilename))
   {
    return result;
   }
   try
   {
    using (package package = package.open(compressedfilename, filemode.create))
    {
     var filelist = directory.enumeratefiles(foldername, "*", searchoption.alldirectories);
     foreach (string filename in filelist)
     {
      
      //the path in the package is all of the subfolders after foldername
      string pathinpackage;
      pathinpackage = path.getdirectoryname(filename).replace(foldername, string.empty) + "/" + path.getfilename(filename);

      uri parturidocument = packurihelper.createparturi(new uri(pathinpackage, urikind.relative));
      packagepart packagepartdocument = package.createpart(parturidocument,"", compressionoption.maximum);
      using (filestream filestream = new filestream(filename, filemode.open, fileaccess.read))
      {
       filestream.copyto(packagepartdocument.getstream());
      }
     }
    }
    result = true;
   }
   catch (exception e)
   {
    throw new exception("error zipping folder " + foldername, e);
   }
   
   return result;
  }

2、将单个文件添加到zip文件中

 /// <summary>
  /// compress a file into a zip archive as the container store
  /// </summary>
  /// <param name="filename">the file to compress</param>
  /// <param name="compressedfilename">the archive file</param>
  /// <param name="overrideexisting">override existing file</param>
  /// <returns></returns>
  static bool packagefile(string filename, string compressedfilename, bool overrideexisting)
  {
   bool result = false;

   if (!file.exists(filename))
   {
    return result;
   }

   if (!overrideexisting && file.exists(compressedfilename))
   {
    return result;
   }

   try
   {
    uri parturidocument = packurihelper.createparturi(new uri(path.getfilename(filename), urikind.relative));
    
    using (package package = package.open(compressedfilename, filemode.openorcreate))
    {
     if (package.partexists(parturidocument))
     {
      package.deletepart(parturidocument);
     }

     packagepart packagepartdocument = package.createpart(parturidocument, "", compressionoption.maximum);
     using (filestream filestream = new filestream(filename, filemode.open, fileaccess.read))
     {
      filestream.copyto(packagepartdocument.getstream());
     }
    }
    result = true;
   }
   catch (exception e)
   {
    throw new exception("error zipping file " + filename, e);
   }
   
   return result;
  }

3、zip文件解压

/// <summary>
  /// extract a container zip. note: container must be created as open packaging conventions (opc) specification
  /// </summary>
  /// <param name="foldername">the folder to extract the package to</param>
  /// <param name="compressedfilename">the package file</param>
  /// <param name="overrideexisting">override existing files</param>
  /// <returns></returns>
  static bool uncompressfile(string foldername, string compressedfilename, bool overrideexisting)
  {
   bool result = false;
   try
   {
    if (!file.exists(compressedfilename))
    {
     return result;
    }

    directoryinfo directoryinfo = new directoryinfo(foldername);
    if (!directoryinfo.exists)
     directoryinfo.create();

    using (package package = package.open(compressedfilename, filemode.open, fileaccess.read))
    {
     foreach (packagepart packagepart in package.getparts())
     {
      extractpart(packagepart, foldername, overrideexisting);
     }
    }

    result = true;
   }
   catch (exception e)
   {
    throw new exception("error unzipping file " + compressedfilename, e);
   }
   
   return result;
  }

  static void extractpart(packagepart packagepart, string targetdirectory, bool overrideexisting)
  {
   string stringpart = targetdirectory + httputility.urldecode(packagepart.uri.tostring()).replace('\\', '/');

   if (!directory.exists(path.getdirectoryname(stringpart)))
    directory.createdirectory(path.getdirectoryname(stringpart));

   if (!overrideexisting && file.exists(stringpart))
    return;
   using (filestream filestream = new filestream(stringpart, filemode.create))
   {
    packagepart.getstream().copyto(filestream);
   }
  }

使用package压缩文件会在zip文件自动生成[content_type].xml,用来描述zip文件解压支持的文件格式。

  <?xml version="1.0" encoding="utf-8" ?> 
<types xmlns="http://schemas.openxmlformats.org/package/2006/content-types">
 <default extension="vsixmanifest" contenttype="text/xml" /> 
 <default extension="dll" contenttype="application/octet-stream" /> 
 <default extension="png" contenttype="application/octet-stream" /> 
 <default extension="txt" contenttype="text/plain" /> 
 <default extension="pkgdef" contenttype="text/plain" /> 
</types>

同样,如果zip文件不包含[content_type].xml文件,或者[content_type].xml文件不包含所对应扩展名的描述(手动添加的[content_type].xml也是可以),将无法解压文件。

 二、使用第三方类库

zip的压缩和解压使用比较的有sharpziplib和dotnetzip。

1、sharpziplib,也称为“#ziplib”,基于gpl开源,支持zip,gzip,tar和bzip2的压缩和解压缩。

支持.net 1.1,net 2.0(3.5、4.0).

(1)zip压缩

 public static void zip(string srcfile, string dstfile, int buffersize)
{
 filestream filestreamin = new filestream
 (srcfile, filemode.open, fileaccess.read);
 filestream filestreamout = new filestream
 (dstfile, filemode.create, fileaccess.write);
 zipoutputstream zipoutstream = new zipoutputstream(filestreamout);
 byte[] buffer = new byte<buffersize />;
 zipentry entry = new zipentry(path.getfilename(srcfile));
 zipoutstream.putnextentry(entry);
 int size;
 do
 {
  size = filestreamin.read(buffer, 0, buffer.length);
  zipoutstream.write(buffer, 0, size);
 } while (size > 0);
 zipoutstream.close();
 filestreamout.close();
 filestreamin.close();
}

(2)解压zip

  public static void unzip(string srcfile, string dstfile, int buffersize)
{
 filestream filestreamin = new filestream
 (srcfile, filemode.open, fileaccess.read);
 zipinputstream zipinstream = new zipinputstream(filestreamin);
 zipentry entry = zipinstream.getnextentry();
 filestream filestreamout = new filestream
 (dstfile + @"\" + entry.name, filemode.create, fileaccess.write);
 int size;
 byte[] buffer = new byte<buffersize />;
 do
 {
  size = zipinstream.read(buffer, 0, buffer.length);
  filestreamout.write(buffer, 0, size);
 } while (size > 0);
 zipinstream.close();
 filestreamout.close();
 filestreamin.close();
}

2、dotnetlib,是基于”ws-pl”开源,使用比较简单

(1)压缩

  using (zipfile zip = new zipfile())
 {
 zip.addfile("readme.txt");
 zip.addfile("7440-n49th.png");
 zip.addfile("2008_annual_report.pdf");  
 zip.save("archive.zip");
 }

(2)解压

 private void myextract()
 {
  string ziptounpack = "c1p3sml.zip";
  string unpackdirectory = "extracted files";
  using (zipfile zip1 = zipfile.read(ziptounpack))
  {
   // here, we extract every entry, but we could extract conditionally
   // based on entry name, size, date, checkbox status, etc. 
   foreach (zipentry e in zip1)
   {
   e.extract(unpackdirectory, extractexistingfileaction.overwritesilently);
   }
  }
 }

三、在.net 4.5使用ziparchive、zipfile等类压缩和解压

 static void main(string[] args)
  {
   string zippath = @"c:\users\exampleuser\start.zip";
   string extractpath = @"c:\users\exampleuser\extract";
   string newfile = @"c:\users\exampleuser\newfile.txt";

   using (ziparchive archive = zipfile.open(zippath, ziparchivemode.update))
   {
    archive.createentryfromfile(newfile, "newentry.txt");
    archive.extracttodirectory(extractpath);
   } 
  }

以上就是本文的全部内容,希望对大家的学习有所帮助,也希望大家多多支持。