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ASP.NET（從v2.0起）如何壓縮、解壓縮檔案呢？

我找到微軟的一些範例，僅供參考：

System.IO.Compression 命名空間
System.IO.Compression 命名空間包含提供資料流基本壓縮和解壓縮服務的類別。

http://msdn.microsoft.com/zh-tw/library/system.io.compression.aspx
下列程式碼範例會示範如何使用 GZipStream 類別，以壓縮及解壓縮檔案。

 

Visual Basic語法（C#語法請看上面的URL，在此不列出）

....................................................................................................................

Imports System

Imports System.IO

Imports System.IO.Compression

Public Class GZipTest

    Shared msg As String

    Private Const buffer_size As Integer = 100

    Public Shared Function ReadAllBytesFromStream(ByVal stream As Stream, ByVal buffer() As Byte) As Integer

        ' Use this method is used to read all bytes from a stream.

        Dim offset As Integer = 0

        Dim totalCount As Integer = 0

        While True

            Dim bytesRead As Integer = stream.Read(buffer, offset, buffer_size)

            If bytesRead = 0 Then

                Exit While

            End If

            offset += bytesRead

            totalCount += bytesRead

        End While

        Return totalCount

    End Function 'ReadAllBytesFromStream結束

    Public Shared Function CompareData(ByVal buf1() As Byte, ByVal len1 As Integer, ByVal buf2() As Byte, ByVal len2 As Integer) As Boolean

        ' 兩個Buffer之間，作比較。Use this method to compare data from two different buffers.

        If len1 <> len2 Then

            msg = "Number of bytes in two buffer are different" & len1 & ":" & len2

            MsgBox(msg)

            Return False

        End If

        Dim i As Integer

        For i = 0 To len1 - 1

            If buf1(i) <> buf2(i) Then

                msg = "byte " & i & " is different " & buf1(i) & "|" & buf2(i)

                MsgBox(msg)

                Return False

            End If

        Next i

        msg = "All bytes compare（比較完畢～）."

        MsgBox(msg)

        Return True

    End Function 'CompareData結束

    Public Shared Sub GZipCompressDecompress(ByVal filename As String)

        msg = "Test compression and decompression on file " & filename

        MsgBox(msg)

        Dim infile As FileStream

        Try

            ' Open the file as a FileStream object.

            infile = New FileStream(filename, FileMode.Open, FileAccess.Read, FileShare.Read)

            Dim buffer(infile.Length - 1) As Byte

            ' Read the file to ensure it is readable.

            Dim count As Integer = infile.Read(buffer, 0, buffer.Length)

            If count <> buffer.Length Then

                infile.Close()

                msg = "Test Failed: Unable to read data from file（讀不到檔案！）"

                MsgBox(msg)

                Return

            End If

            infile.Close()

            Dim ms As New MemoryStream()

            ' Use the newly created memory stream for the compressed data.壓縮檔案

            Dim compressedzipStream As New GZipStream(ms, CompressionMode.Compress, True)

            compressedzipStream.Write(buffer, 0, buffer.Length)

            ' Close the stream.

            compressedzipStream.Close()

            msg = "原本的Original size: " & buffer.Length & ",  壓縮後Compressed size: " & ms.Length

            MsgBox(msg)

            ' ==============================================

            ' Reset the memory stream position to begin decompression. 解壓縮！！

            ms.Position = 0

            Dim zipStream As New GZipStream(ms, CompressionMode.Decompress)

            Dim decompressedBuffer(buffer.Length + buffer_size) As Byte

            ' Use the ReadAllBytesFromStream to read the stream.

            Dim totalCount As Integer = GZipTest.ReadAllBytesFromStream(zipStream, decompressedBuffer)

            msg = "Decompressed（解壓縮） " & totalCount & " bytes"

            MsgBox(msg)

            If Not GZipTest.CompareData(buffer, buffer.Length, decompressedBuffer, totalCount) Then

                msg = "Error. The two buffers did not compare."

                MsgBox(msg)

            End If

            zipStream.Close()

        Catch e As Exception

            msg = "Error: The file being read contains invalid data."

            MsgBox(msg)

        End Try

    End Sub 'GZipCompressDecompress結束

    Public Shared Sub Main(ByVal args() As String)      '主程式

        Dim usageText As String = "Usage: GZIPTEST <inputfilename>"

        'If no file name is specified, write usage text.

        If args.Length = 0 Then

               Console.WriteLine(usageText)

        Else

            If File.Exists(args(0)) Then

                   GZipCompressDecompress(args(0))

            End If

        End If

    End Sub 'Main結束

End Class 'GZipTest 

 

另外，我在估狗上也找到一些不錯的文章，一併列出來給大家參考：

http://aspalliance.com/1348_Understanding_Compression_and_Decompression_in_ASPNET_20.all
http://211.147.225.34/gate/big5/dotnet.chinaitlab.com/CSharp/378794.html
http://blog.csdn.net/21aspnet/archive/2007/06/13/1649810.aspx

小喵大大的文章：使用自訂的類別透過SharpZip執行Zip壓縮、解壓縮(VB.NET)
http://blog.blueshop.com.tw/topcat/archive/2008/02/04/54267.aspx

 

 

 

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