在FCL2.0中增加了System.IO.Compression命名空间, 用以进行文件压缩和解压操作，如下所示：
using System;
using System.IO;
using System.IO.Compression;
namespace Skyiv.Helper
{
static class Zip
{
public static void CompressFile(string sourceFile, string destinationFile)
{
if (!File.Exists(sourceFile)) throw new FileNotFoundException();
using (FileStream sourceStream = new FileStream(sourceFile, FileMode.Open, FileAccess.Read, FileShare.Read))
{
byte [] buffer = new byte[sourceStream.Length];
int checkCounter = sourceStream.Read(buffer, 0, buffer.Length);
if (checkCounter != buffer.Length) throw new ApplicationException();
using (FileStream destinationStream = new FileStream(destinationFile, FileMode.OpenOrCreate, FileAccess.Write))
{
using (GZipStream compressedStream = new GZipStream(destinationStream, CompressionMode.Compress, true))
{
compressedStream.Write(buffer, 0, buffer.Length);
}
}
}
}
public static void DecompressFile(string sourceFile, string destinationFile)
{
if (!File.Exists( sourceFile)) throw new FileNotFoundException();
using (FileStream sourceStream = new FileStream(sourceFile, FileMode.Open))
{
byte [] quartetBuffer = new byte[4];
int position = (int)sourceStream.Length - 4;
sourceStream.Position = position;
sourceStream.Read(quartetBuffer, 0, 4);
sourceStream.Position = 0;
int checkLength = BitConverter.ToInt32(quartetBuffer, 0);
byte[] buffer = new byte[checkLength + 100];
using (GZipStream decompressedStream = new GZipStream(sourceStream, CompressionMode.Decompress, true))
{
int total = 0;
for (int offset = 0; ; )
{
int bytesRead = decompressedStream.Read(buffer, offset, 100);
if (bytesRead == 0) break;
offset += bytesRead;
total += bytesRead;
}
using (FileStream destinationStream = new FileStream(destinationFile, FileMode.Create))
{
destinationStream.Write(buffer, 0, total);
destinationStream.Flush();
}
}
}
}
}
}
using System;
using System.IO;
using Skyiv.Helper;
namespace Skyiv.Test
{
sealed class TestMain
{
static void Main()
{
try
{
string [] nameList = {"zip.zip", "zip.cs", "zip.txt"};
Zip.CompressFile(nameList[1], nameList[0]);
Zip.DecompressFile(nameList[0], nameList[2]);
foreach (string name in nameList)
{
Console.WriteLine("{0,-11}: {1,11:N0} bytes", name, new FileInfo(name).Length);
}
}
catch (Exception ex)
{
Console.WriteLine(ex.Message);
}
}
}
}
运行结果如下:
zip.zip : 773 bytes
zip.cs : 2,196 bytes
zip.txt : 2,196 bytes
但是，如果有使用Zip.DecompressFile()方法去解压标准的ZIP文件，就会出现以下错误：
GZip 头中的幻数不正确。请确保正在传入 GZip 流。
此外，使用Zip.CompressFile()方法也不能将多个文件放入一个ZIP包。
看来，FCL2.0还是不能处理标准的ZIP文件，我目前是使用第三方的ICSharpZipLib来处理ZIP文件：
http://www.icsharpcode.net/OpenSource/SharpZipLib/Download.aspx不知各位是使用什么方案来处理ZIP文件的?