【.NET】利用SharpZipLib压缩与解压文件夹中的所有文件、内存中动态压缩解压数据、内存中压缩与解压文本

SharpZipLib是一个非常优秀的.NET环境下的ZIP文档压缩与解压组件，免费且开源。

本篇文章介绍一下如何使用该组件压缩一个文件夹中的所有文件到ZIP文档、解压一个ZIP文档到文件夹，以及如何利用SharpZipLib在内存中动态的加解压数据。

下载最新版的SharpZipLib http://www.icsharpcode.net/OpenSource/SharpZipLib/Download.aspx

Imports System.IO
Imports System.Text

Imports ICSharpCode
Imports ICSharpCode.SharpZipLib
Imports ICSharpCode.SharpZipLib.Zip
Imports ICSharpCode.SharpZipLib.Zip.Compression
Imports ICSharpCode.SharpZipLib.Core

Public Class iZip

''' <summary>加压数据</summary>
''' <param name="data">数据</param>
''' <param name="offset">起始偏移</param>
''' <param name="length">长度</param>
''' <param name="level">压缩级别</param>
Public Shared Function Compress(ByVal data As Byte(), Optional ByVal offset As Integer = 0, Optional ByVal length As Integer = -1, Optional ByVal level As Integer = 9) As Byte()

If data Is Nothing OrElse data.Length = 0 Then Return Nothing
If offset < 0 Then offset = 0
If length < 0 Then length = data.Length
If level < 0 Then level = 1
If level > 9 Then level = 9

Dim ms As New MemoryStream
Dim def As New Deflater

def.SetLevel(level)
def.SetInput(data, offset, length)
Dim output(&H400 - 1) As Byte
Do Until def.IsFinished
Dim count As Integer = def.Deflate(output)
ms.Write(output, 0, count)
Loop

Dim ret As Byte() = ms.ToArray
ms.Close()
Return ret
End Function

''' <summary>加压字符</summary>
''' <param name="str">字符</param>
''' <param name="enc">编码</param>
''' <param name="level">压缩级别</param>
Public Shared Function CompressString(ByVal str As String, Optional ByVal enc As Encoding = Nothing, Optional ByVal level As Integer = 9) As Byte()
If enc Is Nothing Then enc = Encoding.Default
Dim data As Byte() = enc.GetBytes(str)
Return Compress(data, , , level)
End Function

''' <summary>解压数据</summary>
''' <param name="data">数据</param>
Public Shared Function Decompress(ByVal data As Byte()) As Byte()
If data Is Nothing OrElse data.Length < 1 Then Return Nothing

Dim ms As New MemoryStream
Dim inf As New Inflater
inf.SetInput(data)
Dim buffer(&H400 - 1) As Byte
Do Until inf.IsFinished
Dim count As Integer = inf.Inflate(buffer)
ms.Write(buffer, 0, count)
Loop

Dim ret As Byte() = ms.ToArray
ms.Close()

Return ret
End Function

''' <summary>解压字符</summary>
''' <param name="data">数据</param>
''' <param name="enc">编码</param>
Public Shared Function DecompressString(ByVal data As Byte(), Optional ByVal enc As Encoding = Nothing) As String
If enc Is Nothing Then enc = Encoding.Default

Dim bs As Byte() = Decompress(data)
Return enc.GetString(bs)
End Function

''' <summary>快速加压</summary>
Public Shared Sub FastCreateZip(ByVal zipPath As String, ByVal folderPath As String, Optional ByVal fileFilter As String = "", Optional ByVal password As String = Nothing)
Dim fz As New FastZip
If password <> Nothing Then fz.Password = password
fz.CreateZip(zipPath, folderPath, True, fileFilter)
End Sub

''' <summary>快速解压</summary>
Public Shared Sub FastExtractZip(ByVal zipPath As String, ByVal folderPath As String, Optional ByVal fileFilter As String = "", Optional ByVal password As String = Nothing)
Dim fz As New FastZip
If password <> Nothing Then fz.Password = password
fz.ExtractZip(zipPath, folderPath, fileFilter)
End Sub

''' <summary>解压ZIP文件到目录</summary>
''' <param name="zipPath">ZIP文件路径</param>
''' <param name="folderPath">目标文件夹</param>
''' <param name="password">密码</param>
''' <param name="overwrite">是否覆盖文件</param>
Public Shared Sub DecompressZip(ByVal zipPath As String, ByVal folderPath As String, Optional ByVal password As String = Nothing, Optional ByVal overwrite As Boolean = True)
' 初始化文档、密码、目标文件夹路径
Dim z As New ZipInputStream(File.OpenRead(zipPath))
If password <> Nothing Then z.Password = password
If folderPath = Nothing Then
'folderPath = HttpContext.Current.Server.MapPath("~/")
folderPath = Application.StartupPath
End If
If Not folderPath.EndsWith("\") Then folderPath &= "\"
If Not Directory.Exists(folderPath) Then Directory.CreateDirectory(folderPath)

Dim t As ZipEntry
Dim fp As String

' 开始循环解压
Do
t = z.GetNextEntry
If t Is Nothing Then Exit Do
fp = folderPath & t.Name
' 如果是文件夹则创建文件夹
If t.IsDirectory AndAlso Not Directory.Exists(fp) Then
Directory.CreateDirectory(fp)
ElseIf t.IsFile Then
' 如果是文件则解压文件
If (Not File.Exists(fp)) OrElse (File.Exists(fp) And overwrite) Then
Dim sw As FileStream = File.Create(fp)
Dim size As Integer
Dim data(2048) As Byte
Do '循环读取数据
size = z.Read(data, 0, data.Length)
If size = 0 Then Exit Do
sw.Write(data, 0, size)
Loop
sw.Close()
File.SetLastWriteTime(fp, t.DateTime) '更新创建日期
End If

End If
Loop

z.Close()
End Sub

''' <summary>压缩某个目录内全部文档到ZIP</summary>
''' <param name="zipPath">ZIP路径</param>
''' <param name="folderPath">目标目录</param>
''' <param name="level">压缩级别</param>
''' <param name="password">密码</param>
Public Shared Sub CompressFile(ByVal zipPath As String, ByVal folderPath As String, Optional ByVal level As Integer = 9, Optional ByVal password As String = Nothing)

If Not Directory.Exists(folderPath) Then Return
If folderPath.EndsWith("\") Then folderPath &= "\"

Dim z As New ZipOutputStream(File.Create(zipPath))
z.SetLevel(level)
If password <> Nothing Then z.Password = password

Dim fn As String, buffer(4096) As Byte
Dim di As Integer = folderPath.Length + 1

' 先将主目录下所有文件加入文档
For Each f As String In Directory.GetFiles(folderPath, "*", SearchOption.TopDirectoryOnly)
fn = f.Remove(0, di)
z.PutNextEntry(New ZipEntry(fn))
' 将文件数据写入ZIP
Using fs As FileStream = File.OpenRead(f)
StreamUtils.Copy(fs, z, buffer)
End Using
Next

' 枚举所有文件夹
For Each d As String In Directory.GetDirectories(folderPath, "*", SearchOption.AllDirectories)
fn = d.Remove(0, di) & "\"
z.PutNextEntry(New ZipEntry(fn))
' 枚举所有文件
For Each f As String In Directory.GetFiles(d, "*", SearchOption.TopDirectoryOnly)
fn = f.Remove(0, di)
z.PutNextEntry(New ZipEntry(fn))
Using fs As FileStream = File.OpenRead(f)
StreamUtils.Copy(fs, z, buffer)
End Using
Next
Next

z.Close()
End Sub

End Class

其中数据动态加解压的代码分析来自Lucene.NET，其他的是参考网络上部分文章（来源不可考）。

我稍微封装了一下SharpZipLib的方法，可以更实用更方便一些。

实际上SharpZipLib有一个FastZip类，也很方便，但效率就稍微比自己写的方法低了一点。

代码未严格测试，有BUG或建议请指正。