如何读取并编辑gzip压缩文件内的内容？

你用ZipArchive操作gzip格式的.dat文件时报错，核心原因是gzip是单文件压缩格式，并非多文件归档（如Zip），ZipArchive依赖的中央目录记录在gzip文件中不存在，因此抛出System.IO.InvalidDataException: 'End of Central Directory record could not be found.'错误。

以下是完整的VB.NET实现步骤，包含读取解压、修改LevelName、重新压缩保存：

1. 读取并解压gzip格式的.dat文件 #

gzip仅支持单文件压缩，直接用GZipStream读取解压即可，无需查找归档条目：

Dim inputPath As String = Path.Combine(SelectedWorld, "level.dat")
Dim decompressedContent As String = ""

' 读取并解压文件
Using inputStream As New FileStream(inputPath, FileMode.Open, FileAccess.Read)
    Using gzipStream As New GZipStream(inputStream, CompressionMode.Decompress)
        Using reader As New StreamReader(gzipStream)
            decompressedContent = reader.ReadToEnd()
        End Using
    End Using
End Using

2. 修改LevelName后的内容 #

根据实际格式用正则表达式匹配替换，以下是两种常见格式的处理示例：

Dim newLevelName As String = "你的新存档名称"

' 情况1：格式为 LevelName:OldName 或 LevelName OldName
Dim pattern1 As String = "(LevelName\s*[:=]?\s*)\S+"
decompressedContent = Regex.Replace(decompressedContent, pattern1, "$1" & newLevelName)

' 情况2：格式为 LevelName="OldName"
' Dim pattern2 As String = "(LevelName\s*=\s*")([^"]+)(")
' decompressedContent = Regex.Replace(decompressedContent, pattern2, "$1" & newLevelName & "$3")

3. 重新压缩并保存修改后的内容 #

覆盖原文件或保存到新路径，示例为覆盖原文件：

Using outputStream As New FileStream(inputPath, FileMode.Create, FileAccess.Write)
    Using gzipStream As New GZipStream(outputStream, CompressionMode.Compress)
        Using writer As New StreamWriter(gzipStream)
            writer.Write(decompressedContent)
        End Using
    End Using
End Using

完整整合代码 #

Imports System.IO
Imports System.IO.Compression
Imports System.Text.RegularExpressions

' 替换为你的实际路径
Dim SelectedWorld As String = "你的存档目录路径"
Dim inputPath As String = Path.Combine(SelectedWorld, "level.dat")
Dim decompressedContent As String = ""

' 读取解压
Using inputStream As New FileStream(inputPath, FileMode.Open, FileAccess.Read)
    Using gzipStream As New GZipStream(inputStream, CompressionMode.Decompress)
        Using reader As New StreamReader(gzipStream)
            decompressedContent = reader.ReadToEnd()
        End Using
    End Using
End Using

' 修改LevelName
Dim newLevelName As String = "MyNewWorld"
Dim pattern As String = "(LevelName\s*[:=]?\s*)\S+"
decompressedContent = Regex.Replace(decompressedContent, pattern, "$1" & newLevelName)

' 重新压缩保存
Using outputStream As New FileStream(inputPath, FileMode.Create, FileAccess.Write)
    Using gzipStream As New GZipStream(outputStream, CompressionMode.Compress)
        Using writer As New StreamWriter(gzipStream)
            writer.Write(decompressedContent)
        End Using
    End Using
End Using

MsgBox("LevelName修改完成")

关键注意事项 #

• 不要用ZipArchive处理gzip文件：gzip无归档目录结构，ZipArchive仅适用于多文件Zip格式。
• 正则表达式需适配实际格式：如果你的LevelName格式与示例不同，可调整正则匹配规则。

内容的提问来源于stack exchange，提问作者Amerigo