import org.apache.poi.poifs.crypt.Decryptor; //导入依赖的package包/类
public static XSSFWorkbook decrypt(InputStream input, String password)
    throws IOException {

POIFSFileSystem filesystem = new POIFSFileSystem(input);

EncryptionInfo info = new EncryptionInfo(filesystem);
Decryptor d = Decryptor.getInstance(info);

try {
    if (!d.verifyPassword(password)) {
	throw new RuntimeException(
		"Unable to process: document is encrypted");
    }

    InputStream dataStream = d.getDataStream(filesystem);

    // parse dataStream
    return new XSSFWorkbook(dataStream);

} catch (GeneralSecurityException ex) {
    throw new RuntimeException("Unable to process encrypted document",
	    ex);
}

   }
 

import org.apache.poi.poifs.crypt.Decryptor; //导入依赖的package包/类
public static InputStream convertEncryptedXlsx2DecryptedXlsx(InputStream is)
		throws IOException {
	POIFSFileSystem fs = new POIFSFileSystem(is);
	EncryptionInfo info = new EncryptionInfo(fs);
	Decryptor d = Decryptor.getInstance(info);
	try {
		d.verifyPassword(Decryptor.DEFAULT_PASSWORD);
		InputStream dataStream = d.getDataStream(fs);
		return dataStream;
	} catch (GeneralSecurityException e) {
		throw new IOException(e);
	}
}
 

import org.apache.poi.poifs.crypt.Decryptor; //导入依赖的package包/类
private void signEncryptedPackage(InputStream tmpFileInputStream, SignatureConfig sc, String password) throws IOException, InvalidFormatException, FormatNotUnderstoodException, XMLSignatureException, MarshalException {

	NPOIFSFileSystem poifsTemp = new NPOIFSFileSystem(tmpFileInputStream);
	EncryptionInfo info = new EncryptionInfo(poifsTemp);
	Decryptor d = Decryptor.getInstance(info);
	try {
		if (!d.verifyPassword(password)) {
			throw new FormatNotUnderstoodException("Error: Cannot decrypt new Excel file (.xlsx) for signing. Invalid password");
		}
		// signing
		OPCPackage pkg = OPCPackage.open(d.getDataStream(poifsTemp));
		sc.setOpcPackage(pkg);
		SignatureInfo si = new SignatureInfo();
		si.setSignatureConfig(sc);
		si.confirmSignature();
		// encrypt again
		Encryptor enc = info.getEncryptor();
		enc.confirmPassword(password);
		NPOIFSFileSystem poifs = new NPOIFSFileSystem();
		OutputStream os = enc.getDataStream(poifs);
		pkg.save(os);
		pkg.close();
		if (os!=null) {
			os.close();
		}
		poifs.writeFilesystem(this.finalOutputStream);
		if (poifs!=null) {
			poifs.close();
		}
		if (poifsTemp!=null) {
			poifsTemp.close();
		}
	} catch (GeneralSecurityException e) {
		
		LOG.error(e);
		throw new FormatNotUnderstoodException("Error: Cannot decrypt new Excel file (.xlsx)  for signing.");
	}
}