我正在学习SAML实现，我经历了spring-security saml示例，目前正在生成的AuthRequest默认发生，我正在尝试自定义我的authRequest。
我一直在浏览opensaml库并且正在尝试实现 WebSSOProfilesImpl 类，其中在 getAuthnRequest（）中我实现了以下代码。
protected AuthnRequest getAuthnRequest(SAMLMessageContext context, WebSSOProfileOptions options,
AssertionConsumerService assertionConsumer,
SingleSignOnService bindingService) throws SAMLException, MetadataProviderException {
SAMLObjectBuilder<AuthnRequest> builder =
(SAMLObjectBuilder<AuthnRequest>) builderFactory.getBuilder
(new QName("urn:oasis:names:tc:xacml:3.0:profile:saml2.0:v2:schema:protocol:wd-13", "XACMLAuthzDecisionQueryType",
"xacml-samlp"));
System.out.println("Builder : "+builder.toString()+" "+builder);
AuthnRequest request = builder.buildObject();
System.out.println("request : "+request.toString());
request.setIsPassive(options.getPassive());
request.setForceAuthn(options.getForceAuthN());
request.setProviderName(options.getProviderName());
request.setVersion(SAMLVersion.VERSION_20);
buildCommonAttributes(context.getLocalEntityId(), request, bindingService);
buildScoping(request, bindingService, options);
builNameIDPolicy(request, options);
buildAuthnContext(request, options);
buildReturnAddress(request, assertionConsumer);
return request;
}
但是当我使用IDP登录到我的IS时，我在 SAMLObjectBuilder 对象中得到NullPointerException。我做错了什么？请帮忙，任何帮助都非常感谢!!!
注意： 我在QName中传递的值是我想要给出的值，我可以遵循XACML-SAML决策查询用例。