用ASP.Net实现文件的在线压缩和解压缩

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　　我们经常会遇到批量上传的问题，也会遇到将某个目录下所有文件都上传到服务器上的问题。那么，如何解决此类问题呢？以前的技术一般采用activex等方式，这里笔者采用sharpzlib来实现，听说vs2005已有压缩和解压缩的解决方案，笔者还没有时间用vs2005，所以就只好使用vs2003 + sharpzlib来解决问题了。

　　1、首先从下载0.84版本的sharpzlib源码及示例码。
　　2、下载下来之后你发现它没有vs2003的解决方案文件，没有关系。你可以自己建立，首先新建一个zipunzip的解决方案，然后，将上面经过解压缩之后的所有文件及目录copy到你的解决方案所在的目录下。
　　3、在vs2003解决方案资源管理器（一般是在右上方中部点的位置）中点击显示所有文件按钮，然后可以见到很多“虚”的图标、文件及文件夹等，可以一次选择它们，然后包含进项目中。
　　4、编译，最好使用release选项，编译完成之后你可以在\bin\release\看到zipunzip.dll的类了。如果你编译时报错，说什么assemblykeyfile之类的，你可以使用强命名工具新建一个，也可以将assemblyinfo.cs中[assembly: assemblykeyfile("。。。。。")]改成:[assembly: assemblykeyfile("")]  (不推荐这样做)。
　　5、新建一个webform项目，添加zipunzip.dll类的引用，然后添加如下文件及内容：

// ------------------------------------------
// 1. attachmentunzip.cs
// ------------------------------------------
using system;
using system.io;
using icsharpcode.sharpziplib.zip;
using icsharpcode.sharpziplib.gzip;
using icsharpcode.sharpziplib.bzip2;
using icsharpcode.sharpziplib.checksums;
using icsharpcode.sharpziplib.zip.compression;
using icsharpcode.sharpziplib.zip.compression.streams;

namespace webzipunzip
{
 public class attachmentunzip
 {
  public attachmentunzip()
  {  
  }
  public static void upzip(string zipfile)
  {
   string []fileproperties=new string[2];
   fileproperties[0]=zipfile;//待解压的文件
   fileproperties[1]=zipfile.substring(0,zipfile.lastindexof("\\")+1);//解压后放置的目标目录
   unzipclass unzc=new unzipclass();
   unzc.unzip(fileproperties);
  }
 }
}

// ---------------------------------------------
// 2. unzipclass.cs
// ---------------------------------------------

using system;
using system.io;
using icsharpcode.sharpziplib.zip;
using icsharpcode.sharpziplib.gzip;
using icsharpcode.sharpziplib.bzip2;
using icsharpcode.sharpziplib.checksums;
using icsharpcode.sharpziplib.zip.compression;
using icsharpcode.sharpziplib.zip.compression.streams;

namespace webzipunzip
{
 public class unzipclass
 {  
  /// <summary>
  /// 解压文件
  /// </summary>
  /// <param name="args">包含要解压的文件名和要解压到的目录名数组</param>
  public void unzip(string[] args)
  {
   zipinputstream s = new zipinputstream(file.openread(args[0]));
   try
   {   
    zipentry theentry;
    while ((theentry = s.getnextentry()) != null)
    {  
     string directoryname = path.getdirectoryname(args[1]);
     string filename      = path.getfilename(theentry.name);

     //生成解压目录
     directory.createdirectory(directoryname);

     if (filename != string.empty)
     {  
      //解压文件到指定的目录
      filestream streamwriter = file.create(args[1]+filename);

      int size = 2048;
      byte[] data = new byte[2048];
      while (true)
      {
       size = s.read(data, 0, data.length);
       if (size > 0)
       {
        streamwriter.write(data, 0, size);
       }
       else
       {
        break;
       }
      }

      streamwriter.close();
     }
    }
    s.close();
   }
   catch(exception eu)
   {
    throw eu;
   }
   finally
   {
    s.close();
   }

  }//end unzip

  public static bool unzipfile(string file, string dir)
  {
   try
   {
    if (!directory.exists(dir))
     directory.createdirectory(dir);
    string filefullname = path.combine(dir,file);
    zipinputstream s = new zipinputstream(file.openread( filefullname ));

    zipentry theentry;
    while ((theentry = s.getnextentry()) != null)
    {
     string directoryname = path.getdirectoryname(theentry.name);
     string filename = path.getfilename(theentry.name);

     if (directoryname != string.empty)
      directory.createdirectory( path.combine(dir, directoryname));

     if (filename != string.empty)
     {
      filestream streamwriter = file.create( path.combine(dir,theentry.name) );
      int size = 2048;
      byte[] data = new byte[2048];
      while (true)
      {
       size = s.read(data, 0, data.length);
       if (size > 0)
       {
        streamwriter.write(data, 0, size);
       }
       else
       {
        break;
       }
      }

      streamwriter.close();
     }
    }
    s.close();
    return true;
   }
   catch (exception)
   {
    throw;
   }
  }

 }//end unzipclass
}

// ----------------------------------------------
// 3. zipclass.cs
// ----------------------------------------------
using system;
using system.io;
using icsharpcode.sharpziplib.zip;
using icsharpcode.sharpziplib.gzip;
using icsharpcode.sharpziplib.bzip2;
using icsharpcode.sharpziplib.checksums;
using icsharpcode.sharpziplib.zip.compression;
using icsharpcode.sharpziplib.zip.compression.streams;

namespace webzipunzip
{
 /// <summary>
 /// 压缩文件
 /// </summary>
 public class zipclass
 {
  public void zipfile(string filetozip, string zipedfile ,int compressionlevel, int blocksize,string password)
  {
   //如果文件没有找到，则报错
   if (! system.io.file.exists(filetozip))
   {
    throw new system.io.filenotfoundexception("the specified file " + filetozip + " could not be found. zipping aborderd");
   }

   system.io.filestream streamtozip = new system.io.filestream(filetozip,system.io.filemode.open , system.io.fileaccess.read);
   system.io.filestream zipfile = system.io.file.create(zipedfile);
   zipoutputstream zipstream = new zipoutputstream(zipfile);
   zipentry zipentry = new zipentry("zippedfile");
   zipstream.putnextentry(zipentry);
   zipstream.setlevel(compressionlevel);
   byte[] buffer = new byte[blocksize];
   system.int32 size =streamtozip.read(buffer,0,buffer.length);
   zipstream.write(buffer,0,size);
   try
   {
    while (size < streamtozip.length)
    {
     int sizeread =streamtozip.read(buffer,0,buffer.length);
     zipstream.write(buffer,0,sizeread);
     size += sizeread;
    }
   }
   catch(system.exception ex)
   {
    throw ex;
   }
   zipstream.finish();
   zipstream.close();
   streamtozip.close();
  }

  public void zipfilemain(string[] args)
  {
   //string[] filenames = directory.getfiles(args[0]);
   string[] filenames = new string[]{args[0]};

   crc32 crc = new crc32();
   zipoutputstream s = new zipoutputstream(file.create(args[1]));

   s.setlevel(6); // 0 - store only to 9 - means best compression

   foreach (string file in filenames)
   {
    //打开压缩文件
    filestream fs = file.openread(file);  
    byte[] buffer = new byte[fs.length];
    fs.read(buffer, 0, buffer.length);
    zipentry entry = new zipentry(file);

    entry.datetime = datetime.now;

    // set size and the crc, because the information
    // about the size and crc should be stored in the header
    // if it is not set it is automatically written in the footer.
    // (in this case size == crc == -1 in the header)
    // some zip programs have problems with zip files that don't store
    // the size and crc in the header.
    entry.size = fs.length;
    fs.close();

    crc.reset();
    crc.update(buffer);

    entry.crc  = crc.value;

    s.putnextentry(entry);

    s.write(buffer, 0, buffer.length);

   } 
   s.finish();
   s.close();
  }
 }
}

// ---------------------------------------------
// 4. webform1.aspx
// ---------------------------------------------
  <%@ page language="c#" codebehind="webform1.aspx.cs" autoeventwireup="false" inherits="webzipunzip.webform1" %> 
<meta content="microsoft visual studio .net 7.1" name=generator>
<meta content=c# name=code_language>
<meta content=javascript name=vs_defaultclientscript>
<meta content=http://schemas.microsoft.com/intellisense/ie5 name=vs_targetschema>
<form id=form1 method=post runat="server"><?xml:namespace prefix = asp /><asp:button id=button1 style="z-index: 101; left: 56px; position: absolute; top: 64px" runat="server" text="压缩"></asp:button><asp:button id=button2 style="z-index: 102; left: 112px; position: absolute; top: 64px" runat="server" text="解压"></asp:button><input id=file1 style="z-index: 103; left: 32px; position: absolute; top: 24px" type=file name=file1 runat="server"> </form></body></html>

//-------------------------------------------
// 5.webform1.aspx.cs
//-------------------------------------------

using system;
using system.collections;
using system.componentmodel;
using system.data;
using system.drawing;
using system.io;
using system.web;
using system.web.sessionstate;
using system.web.ui;
using system.web.ui.webcontrols;
using system.web.ui.htmlcontrols;

namespace webzipunzip
{
 /// <summary>
 /// summary description for webform1.
 /// </summary>
 public class webform1 : system.web.ui.page
 {
  protected system.web.ui.webcontrols.button button1;
  protected system.web.ui.htmlcontrols.htmlinputfile file1;
  protected system.web.ui.webcontrols.button button2;

  private void page_load(object sender, system.eventargs e)
  {
   // put user code to initialize the page here
  }

  #region web form designer generated code
  override protected void oninit(eventargs e)
  {
   //
   // codegen: this call is required by the asp.net web form designer.
   //
   initializecomponent();
   base.oninit(e);
  }

  /// <summary>
  /// required method for designer support - do not modify
  /// the contents of this method with the code editor.
  /// </summary>
  private void initializecomponent()
  {   
   this.button1.click += new system.eventhandler(this.button1_click);
   this.button2.click += new system.eventhandler(this.button2_click);
   this.load += new system.eventhandler(this.page_load);

  }
  #endregion

  #region 压缩
  private void button1_click(object sender, system.eventargs e)
  {
   string []fileproperties=new string[2];  
   string fullname=this.file1.postedfile.filename;//c:\test\a.txt
   string destpath=system.io.path.getdirectoryname(fullname);//c:\test
   //待压缩文件
   fileproperties[0]=fullname;

   //压缩后的目标文件
   fileproperties[1]= destpath +"\\"+ system.io.path.getfilenamewithoutextension(fullname) + ".zip";
   zipclass zc=new zipclass();
   zc.zipfilemain(fileproperties);

   //删除压缩前的文件
   system.io.file.delete(fullname);
  }

  #endregion

  #region 解压
  private void button2_click(object sender, system.eventargs e)
  {
   string fullname=this.file1.postedfile.filename;//c:\test\a.zip
   //解压文件
   //attachmentunzip.upzip(fullname);

//   string[] fileproperties = new string[2];
//   fileproperties[0] = fullname;//待解压的文件
//   fileproperties[1] = system.io.path.getdirectoryname(fullname);//解压后放置的目标目录
//   unzipclass unzc=new unzipclass();
//   unzc.unzip(fileproperties);
   string dir = system.io.path.getdirectoryname(fullname);
   string filename = system.io.path.getfilename(fullname);
   unzipclass.unzipfile(filename, dir);
  }
  #endregion
 }
}

　　ok! 试试看。

　　此方案解决了文件名中文字的问题，目录解压缩问题。
　　至于整个文件夹批量上传并压缩成一个winzip压缩包的问题，没有时间解决了，各位如有解决方案，不妨共享一下。

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