public HashMap<String, HashSet<String>> processResponse(String SAMLResponse) throws Exception {
        //获取saml response xml对象
        Response fetchedResponse = fetchResponse(SAMLResponse);
        Assertion assertion = fetchedResponse.getAssertions().get(0);
        Signature idpSignature = assertion.getSignature();
        HashMap<String, HashSet<String>> claimsContainer = getFieldsFromAssertion(assertion);
        
        if (idpSignature == null)
            throw new RuntimeException("Cannot extract signature from the Identity Provider");
        else {
            //验签
            verifyIDP(idpSignature, "/Users/Downloads/federationmetadata.xml");
        }
        
        return claimsContainer;
    }
    
    public Response fetchResponse(String SAMLResponse) throws Exception {
        byte[] decodedB = Base64.decode(SAMLResponse);
        System.out.println(new String(decodedB));
        ByteArrayInputStream is = new ByteArrayInputStream(decodedB);

        DocumentBuilderFactory documentBuilderFactory = DocumentBuilderFactory.newInstance();
        documentBuilderFactory.setNamespaceAware(true);
        DocumentBuilder docBuilder = documentBuilderFactory.newDocumentBuilder();

        Document document = docBuilder.parse(is);
        Element element = document.getDocumentElement();
    
        Unmarshaller unmarshaller = Configuration.getUnmarshallerFactory().getUnmarshaller(element);
        XMLObject xmlobj = unmarshaller.unmarshall(element);
        Response respObject = (Response) xmlobj;
        
        return respObject;
    }