操作說明：壓縮與解壓縮檔案

發行項
05/09/2023

System.IO.Compression 命名空間包含壓縮及解壓縮檔案和資料流的下列類別。您也可以使用這些類型來讀取和修改壓縮檔案的內容：

下列範例示範您可以搭配壓縮檔案執行的部分作業。這些範例需要將下列 NuGet 套件新增至您的專案：

如果您是使用 .NET Framework，請將這兩個程式庫的參考新增至您的專案：

System.IO.Compression
System.IO.Compression.FileSystem

範例 1：建立和解壓縮 ZIP 檔案

下列範例示範如何使用 ZipFile 類別，建立和解壓縮 .zip 檔案。此範例會將資料夾的內容壓縮至新的 .zip 檔案，然後將該檔案解壓縮至新的資料夾。

若要執行樣本，請在程式資料夾中建立啟動資料夾，並在其中填入要壓縮的檔案。

using System;
using System.IO.Compression;

class Program
{
    static void Main(string[] args)
    {
        string startPath = @".\start";
        string zipPath = @".\result.zip";
        string extractPath = @".\extract";

        ZipFile.CreateFromDirectory(startPath, zipPath);

        ZipFile.ExtractToDirectory(zipPath, extractPath);
    }
}

Imports System.IO.Compression

Module Module1

    Sub Main()
        Dim startPath As String = ".\start"
        Dim zipPath As String = ".\result.zip"
        Dim extractPath As String = ".\extract"

        ZipFile.CreateFromDirectory(startPath, zipPath)

        ZipFile.ExtractToDirectory(zipPath, extractPath)
    End Sub

End Module

範例 2：解壓縮特定的副檔名

下列範例會逐一查看現有 .zip 檔案的內容，並將副檔名為 .txt 的檔案解壓縮。它會使用 ZipArchive 類別來存取 .zip 檔案，以及使用 ZipArchiveEntry 類別來檢查個別項目。 ZipArchiveEntry 物件的擴充方法 ExtractToFile 可在 System.IO.Compression.ZipFileExtensions 類別中使用。

若要執行樣本，請將名為 result.zip 的 .zip 檔案置於您的程式資料夾中。出現提示時，提供要擷取至的資料夾名稱。

重要

當您在解壓縮檔案時，必須尋找惡意的檔案路徑，以免它從您解壓縮的目的目錄逸出。這是所謂的路徑周遊攻擊。以下範例示範如何檢查惡意的檔案路徑，並提供安全的方式來解壓縮。

using System;
using System.IO;
using System.IO.Compression;

class Program
{
    static void Main(string[] args)
    {
        string zipPath = @".\result.zip";

        Console.WriteLine("Provide path where to extract the zip file:");
        string extractPath = Console.ReadLine();

        // Normalizes the path.
        extractPath = Path.GetFullPath(extractPath);

        // Ensures that the last character on the extraction path
        // is the directory separator char.
        // Without this, a malicious zip file could try to traverse outside of the expected
        // extraction path.
        if (!extractPath.EndsWith(Path.DirectorySeparatorChar.ToString(), StringComparison.Ordinal))
            extractPath += Path.DirectorySeparatorChar;

        using (ZipArchive archive = ZipFile.OpenRead(zipPath))
        {
            foreach (ZipArchiveEntry entry in archive.Entries)
            {
                if (entry.FullName.EndsWith(".txt", StringComparison.OrdinalIgnoreCase))
                {
                    // Gets the full path to ensure that relative segments are removed.
                    string destinationPath = Path.GetFullPath(Path.Combine(extractPath, entry.FullName));

                    // Ordinal match is safest, case-sensitive volumes can be mounted within volumes that
                    // are case-insensitive.
                    if (destinationPath.StartsWith(extractPath, StringComparison.Ordinal))
                        entry.ExtractToFile(destinationPath);
                }
            }
        }
    }
}

Imports System.IO
Imports System.IO.Compression

Module Module1

    Sub Main()
        Dim zipPath As String = ".\result.zip"

        Console.WriteLine("Provide path where to extract the zip file:")
        Dim extractPath As String = Console.ReadLine()

        ' Normalizes the path.
        extractPath = Path.GetFullPath(extractPath)

        ' Ensures that the last character on the extraction path
        ' is the directory separator char. 
        ' Without this, a malicious zip file could try to traverse outside of the expected
        ' extraction path.
        If Not extractPath.EndsWith(Path.DirectorySeparatorChar.ToString(), StringComparison.Ordinal) Then
            extractPath += Path.DirectorySeparatorChar
        End If

        Using archive As ZipArchive = ZipFile.OpenRead(zipPath)
            For Each entry As ZipArchiveEntry In archive.Entries
                If entry.FullName.EndsWith(".txt", StringComparison.OrdinalIgnoreCase) Then

                    ' Gets the full path to ensure that relative segments are removed.
                    Dim destinationPath As String = Path.GetFullPath(Path.Combine(extractPath, entry.FullName))

                    ' Ordinal match is safest, case-sensitive volumes can be mounted within volumes that
                    ' are case-insensitive.
                    If destinationPath.StartsWith(extractPath, StringComparison.Ordinal) Then
                        entry.ExtractToFile(destinationPath)
                    End If

                End If
            Next
        End Using
    End Sub

End Module

範例 3：將檔案加入至現有的 .zip 檔案

下列範例使用 ZipArchive 類別存取現有的 .zip 檔案，並將檔案新增至其中。當您將新檔案加入至現有的 .zip 檔案時，會壓縮該檔案。

using System;
using System.IO;
using System.IO.Compression;

namespace ConsoleApplication
{
    class Program
    {
        static void Main(string[] args)
        {
            using (FileStream zipToOpen = new FileStream(@"c:\users\exampleuser\release.zip", FileMode.Open))
            {
                using (ZipArchive archive = new ZipArchive(zipToOpen, ZipArchiveMode.Update))
                {
                    ZipArchiveEntry readmeEntry = archive.CreateEntry("Readme.txt");
                    using (StreamWriter writer = new StreamWriter(readmeEntry.Open()))
                    {
                            writer.WriteLine("Information about this package.");
                            writer.WriteLine("========================");
                    }
                }
            }
        }
    }
}

Imports System.IO
Imports System.IO.Compression

Module Module1

    Sub Main()
        Using zipToOpen As FileStream = New FileStream("c:\users\exampleuser\release.zip", FileMode.Open)
            Using archive As ZipArchive = New ZipArchive(zipToOpen, ZipArchiveMode.Update)
                Dim readmeEntry As ZipArchiveEntry = archive.CreateEntry("Readme.txt")
                Using writer As StreamWriter = New StreamWriter(readmeEntry.Open())
                    writer.WriteLine("Information about this package.")
                    writer.WriteLine("========================")
                End Using
            End Using
        End Using
    End Sub

End Module

範例 4：壓縮和解壓縮 .gz 檔案

您也可以使用 GZipStream 和 DeflateStream 類別壓縮和解壓縮資料。它們會使用相同的壓縮演算法。您可以使用許多常用工具，將寫入至 .gz 檔案的 GZipStream 物件解壓縮。以下範例示範如何使用 GZipStream 類別壓縮和解壓縮檔案目錄：

using System;
using System.IO;
using System.IO.Compression;

public class Program
{
    private static string directoryPath = @".\temp";
    public static void Main()
    {
        DirectoryInfo directorySelected = new DirectoryInfo(directoryPath);
        Compress(directorySelected);

        foreach (FileInfo fileToDecompress in directorySelected.GetFiles("*.gz"))
        {
            Decompress(fileToDecompress);
        }
    }

    public static void Compress(DirectoryInfo directorySelected)
    {
        foreach (FileInfo fileToCompress in directorySelected.GetFiles())
        {
            using (FileStream originalFileStream = fileToCompress.OpenRead())
            {
                if ((File.GetAttributes(fileToCompress.FullName) &
                   FileAttributes.Hidden) != FileAttributes.Hidden & fileToCompress.Extension != ".gz")
                {
                    using (FileStream compressedFileStream = File.Create(fileToCompress.FullName + ".gz"))
                    {
                        using (GZipStream compressionStream = new GZipStream(compressedFileStream,
                           CompressionMode.Compress))
                        {
                            originalFileStream.CopyTo(compressionStream);
                        }
                    }
                    FileInfo info = new FileInfo(directoryPath + Path.DirectorySeparatorChar + fileToCompress.Name + ".gz");
                    Console.WriteLine($"Compressed {fileToCompress.Name} from {fileToCompress.Length.ToString()} to {info.Length.ToString()} bytes.");
                }
            }
        }
    }

    public static void Decompress(FileInfo fileToDecompress)
    {
        using (FileStream originalFileStream = fileToDecompress.OpenRead())
        {
            string currentFileName = fileToDecompress.FullName;
            string newFileName = currentFileName.Remove(currentFileName.Length - fileToDecompress.Extension.Length);

            using (FileStream decompressedFileStream = File.Create(newFileName))
            {
                using (GZipStream decompressionStream = new GZipStream(originalFileStream, CompressionMode.Decompress))
                {
                    decompressionStream.CopyTo(decompressedFileStream);
                    Console.WriteLine($"Decompressed: {fileToDecompress.Name}");
                }
            }
        }
    }
}

Imports System.IO
Imports System.IO.Compression

Module Module1

    Private directoryPath As String = ".\temp"
    Public Sub Main()
        Dim directorySelected As New DirectoryInfo(directoryPath)
        Compress(directorySelected)

        For Each fileToDecompress As FileInfo In directorySelected.GetFiles("*.gz")
            Decompress(fileToDecompress)
        Next
    End Sub

    Public Sub Compress(directorySelected As DirectoryInfo)
        For Each fileToCompress As FileInfo In directorySelected.GetFiles()
            Using originalFileStream As FileStream = fileToCompress.OpenRead()
                If (File.GetAttributes(fileToCompress.FullName) And FileAttributes.Hidden) <> FileAttributes.Hidden And fileToCompress.Extension <> ".gz" Then
                    Using compressedFileStream As FileStream = File.Create(fileToCompress.FullName & ".gz")
                        Using compressionStream As New GZipStream(compressedFileStream, CompressionMode.Compress)

                            originalFileStream.CopyTo(compressionStream)
                        End Using
                    End Using
                    Dim info As New FileInfo(directoryPath & Path.DirectorySeparatorChar & fileToCompress.Name & ".gz")
                    Console.WriteLine($"Compressed {fileToCompress.Name} from {fileToCompress.Length.ToString()} to {info.Length.ToString()} bytes.")

                End If
            End Using
        Next
    End Sub


    Private Sub Decompress(ByVal fileToDecompress As FileInfo)
        Using originalFileStream As FileStream = fileToDecompress.OpenRead()
            Dim currentFileName As String = fileToDecompress.FullName
            Dim newFileName = currentFileName.Remove(currentFileName.Length - fileToDecompress.Extension.Length)

            Using decompressedFileStream As FileStream = File.Create(newFileName)
                Using decompressionStream As GZipStream = New GZipStream(originalFileStream, CompressionMode.Decompress)
                    decompressionStream.CopyTo(decompressedFileStream)
                    Console.WriteLine($"Decompressed: {fileToDecompress.Name}")
                End Using
            End Using
        End Using
    End Sub
End Module

操作說明：壓縮與解壓縮檔案

範例 1：建立和解壓縮 ZIP 檔案

範例 2：解壓縮特定的副檔名

範例 3：將檔案加入至現有的 .zip 檔案

範例 4：壓縮和解壓縮 .gz 檔案

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