用OpenSAML v3从IDP元数据创建凭据对象

Question

我正在尝试验证从SSO Sircle(IDP)返回的SAML响应。为此，我使用SSO circle（https://IDP.ssocircle.com/idp-meta.xml）提供的IDP元数据创建具有IDP公钥的凭据对象，如下所示：

    FilesystemMetadataResolver idpMetadataResolver = new  FilesystemMetadataResolver(new File("C:\\idp_metadata.xml"));
    idpMetadataResolver.setRequireValidMetadata(true);
    idpMetadataResolver.setParserPool(new BasicParserPool());
    idpMetadataResolver.initialize();

    MetadataCredentialResolver credentialResolver = new MetadataCredentialResolver();

    credentialResolver.setRoleDescriptorResolver(new BasicRoleDescriptorResolver(idpMetadataResolver));

    CriteriaSet criteriaSet = new CriteriaSet();
    criteriaSet.add(new EntityIdCriterion("https://idp.ssocircle.com"));
    criteriaSet.add(new EntityRoleCriterion(IDPSSODescriptor.DEFAULT_ELEMENT_NAME));

    X509Credential credential = (X509Credential)credentialResolver.resolveSingle(criteriaSet);

但是，在尝试初始化IDPMetadataResolver时，这会引发异常：

net.shibboleth.utilities.java.support.component.ComponentInitializationException: Component identifier can not be null
at net.shibboleth.utilities.java.support.component.AbstractIdentifiedInitializableComponent.doInitialize(AbstractIdentifiedInitializableComponent.java:65)
at org.opensaml.saml.metadata.resolver.impl.AbstractMetadataResolver.doInitialize(AbstractMetadataResolver.java:188)
at net.shibboleth.utilities.java.support.component.AbstractInitializableComponent.initialize(AbstractInitializableComponent.java:61)

我对OpenSAML非常陌生，我主要在网上查看示例和教程，但大多数都是为OpenSAML V2.0编写的。我想知道在初始化对象时是否做错了什么。

Answer 1

经过对OpenSaml3 Java文档和Shibboleth开发社区的深入研究，我想我找到了我的问题的答案。元数据解析器对象需要如下设置：

    FilesystemMetadataResolver idpMetadataResolver = new FilesystemMetadataResolver(new File("C:\\idp.xml"));
    idpMetadataResolver.setRequireValidMetadata(true);
    idpMetadataResolver.setParserPool(XMLObjectProviderRegistrySupport.getParserPool());
    idpMetadataResolver.setId("someidentifier");
    idpMetadataResolver.initialize();