如何将所有文件类型的字节数组转换为字符串

Question

目前我可以从数据库中获取 BLOB 数据类型的数据。所以在代码中它会被存储在byte[]中。现在我可以通过如下提及字符集 (eg.UTF-8) 将字节数组转换为字符串：

public byte[] mtdFileEncryption(byte[] myData,String fileName) throws DNSException, Exception
{
    String strLocalFolder = SysProperties.getprocessFile_LOCAL_FOLDER();
    String strOnlineSSTPublicKey = SysProperties.getOnline_SST_ENCRYPTION_PUBLIC_KEY();
    String strFilename = fileName;
    PGPFileEncryptor fileEncryptor = new com.test.PGPFileEncryptor();

    File outputFile = null;
    FileOutputStream fos = null;
    OutputStreamWriter osw = null;
    BufferedWriter bufferOutput = null;

    File toFile = new File(strLocalFolder);
    if(!toFile.isDirectory())
    {
    //Create temp folder
    toFile.mkdir();
    }

    try
    {
        //generate file to local folder
        //outputFile = new File(strLocalFolder + strFilename + ".txt");

        outputFile = new File(strLocalFolder + strFilename);
        fos = new FileOutputStream(outputFile);
        osw = new OutputStreamWriter(fos);
        bufferOutput = new BufferedWriter(osw);
        //WORKING FOR TXT
        String str = new String(myData, "UTF-8");
        bufferOutput.write(str);

    }catch(Exception e)
    {
        e.printStackTrace();
        throw e;
    }finally
    {
        if(bufferOutput != null)
        {
            bufferOutput.close();
            bufferOutput = null;
        }

        if (osw != null)
        {
            osw.close();
            osw = null;
        }

        if (fos != null)
        {
            fos.close();
            fos = null;
        }
    }

也就是说下面可以转成字符串，我可以查看.txt存储文件的内容

//WORKING FOR TXT
        String str = new String(myData, "UTF-8");
        bufferOutput.write(str);

但这不会发生在其他文件、.pdf 或 .xls 上我无法查看内容。我可以知道如何在不指定字符集的情况下将所有文件类型（.pdf、.xls 等）的字节数组 (myData) 转换为字符串吗？

以下是字节数组[]如何传入方法。 file_content 是来自 table 的 BLOB 数据类型。

    String contentString = rsStatementRequest.getValue("file_content");
                    BASE64Decoder en = new BASE64Decoder();
                    byte[] contentBytes = en.decodeBuffer(contentString);
contentBytes = mtdFileEncryption(contentBytes,fileName);

Answer 1

我建议用二进制写byte[] BLOB。写作是因为文本很可能会损坏它，尤其是如果它是加密的。

public void mtdFileEncryption(byte[] myData,String fileName) throws IOException {
    String strLocalFolder = SysProperties.getprocessFile_LOCAL_FOLDER();
    new File(strLocalFolder).mkdir();

    try (FileOutputStream fos = new FileOutputStream(new File(strLocalFolder, fileName)) {
         fos.write(myData);
    }
}

如何将所有文件类型的字节数组转换为字符串

How to convert byte array to string for all file types

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