将文件转换为 Base64String 并再次转换回来

Question

标题说明了一切：

1. 我像这样读了 tar.gz 存档
2. 将文件分解为字节数组
3. 将这些字节转换为 Base64 字符串
4. 将该 Base64 字符串转换回字节数组
5. 将这些字节写回到新的 tar.gz 文件中

我可以确认两个文件的大小相同（以下方法返回 true），但我无法再提取副本版本。

我错过了什么吗？

Boolean MyMethod(){
    using (StreamReader sr = new StreamReader("C:\...\file.tar.gz")) {
        String AsString = sr.ReadToEnd();
        byte[] AsBytes = new byte[AsString.Length];
        Buffer.BlockCopy(AsString.ToCharArray(), 0, AsBytes, 0, AsBytes.Length);
        String AsBase64String = Convert.ToBase64String(AsBytes);

        byte[] tempBytes = Convert.FromBase64String(AsBase64String);
        File.WriteAllBytes(@"C:\...\file_copy.tar.gz", tempBytes);
    }
    FileInfo orig = new FileInfo("C:\...\file.tar.gz");
    FileInfo copy = new FileInfo("C:\...\file_copy.tar.gz");
    // Confirm that both original and copy file have the same number of bytes
    return (orig.Length) == (copy.Length);
}

编辑：工作示例要简单得多（感谢@T.S.）：

Boolean MyMethod(){
    byte[] AsBytes = File.ReadAllBytes(@"C:\...\file.tar.gz");
    String AsBase64String = Convert.ToBase64String(AsBytes);

    byte[] tempBytes = Convert.FromBase64String(AsBase64String);
    File.WriteAllBytes(@"C:\...\file_copy.tar.gz", tempBytes);

    FileInfo orig = new FileInfo(@"C:\...\file.tar.gz");
    FileInfo copy = new FileInfo(@"C:\...\file_copy.tar.gz");
    // Confirm that both original and copy file have the same number of bytes
    return (orig.Length) == (copy.Length);
}

Answer 1

如果您出于某种原因想要将文件转换为 base-64 字符串。就像如果你想通过互联网等传递它......你可以这样做

Byte[] bytes = File.ReadAllBytes("path");
String file = Convert.ToBase64String(bytes);

相应地，读回文件：

Byte[] bytes = Convert.FromBase64String(b64Str);
File.WriteAllBytes(path, bytes);

Answer 2

private String encodeFileToBase64Binary(File file){    
String encodedfile = null;  
try {  
    FileInputStream fileInputStreamReader = new FileInputStream(file);  
    byte[] bytes = new byte[(int)file.length()];
    fileInputStreamReader.read(bytes);  
    encodedfile = Base64.encodeBase64(bytes).toString();  
} catch (FileNotFoundException e) {  
    // TODO Auto-generated catch block  
    e.printStackTrace();  
} catch (IOException e) {  
    // TODO Auto-generated catch block  
    e.printStackTrace();  
}  
    return encodedfile;  
}

Answer 3

VB.NET 中的另一个工作示例：

Public Function base64Encode(ByVal myDataToEncode As String) As String
    Try
        Dim myEncodeData_byte As Byte() = New Byte(myDataToEncode.Length - 1) {}
        myEncodeData_byte = System.Text.Encoding.UTF8.GetBytes(myDataToEncode)
        Dim myEncodedData As String = Convert.ToBase64String(myEncodeData_byte)
        Return myEncodedData
    Catch ex As Exception
        Throw (New Exception("Error in base64Encode" & ex.Message))
    End Try
    '
End Function

Answer 4

对于 Java，请考虑使用 Apache Commons FileUtils:

/**
 * Convert a file to base64 string representation
 */
public String fileToBase64(File file) throws IOException {
    final byte[] bytes = FileUtils.readFileToByteArray(file);
    return Base64.getEncoder().encodeToString(bytes);
}

/**
 * Convert base64 string representation to a file
 */
public void base64ToFile(String base64String, String filePath) throws IOException {
    byte[] bytes = Base64.getDecoder().decode(base64String);
    FileUtils.writeByteArrayToFile(new File(filePath), bytes);
}