private POIFSFileSystem openFileSystemAndEncrypt(File file) throws Exception {
        POIFSFileSystem fileSystem = new POIFSFileSystem();
        Encryptor encryptor = new EncryptionInfo(EncryptionMode.standard).getEncryptor();
        encryptor.confirmPassword(writeWorkbookHolder.getPassword());
        try (OPCPackage opcPackage = OPCPackage.open(file, PackageAccess.READ_WRITE);
             OutputStream outputStream = encryptor.getDataStream(fileSystem)) {
            opcPackage.save(outputStream);
        }
        return fileSystem;
    }
Opens a file system and encrypts the given file.

This method creates a new POIFSFileSystem instance, sets up an Encryptor with a standard encryption mode,
and confirms the password for encryption. It then opens the provided file in read-write mode, saves its content
into an encrypted output stream, and finally returns the encrypted file system.

@param file The file to be encrypted.
@return An encrypted POIFSFileSystem object.
@throws Exception If any error occurs during the encryption process or file handling.
fastexcel-core/src/main/java/cn/idev/excel/context/WriteContextImpl.java