要通过Java读取来自SSO提供商的SAML响应，您可以使用开源的SAML库，例如OpenSAML。以下是一个示例代码，演示如何使用OpenSAML解析SAML响应：

首先，您需要添加OpenSAML依赖项。您可以在Maven pom.xml文件中添加以下依赖项：

    org.opensaml
    opensaml
    3.4.4

然后，您可以使用以下代码来解析SAML响应：

import org.opensaml.core.config.Configuration;
import org.opensaml.core.config.InitializationService;
import org.opensaml.core.xml.XMLObject;
import org.opensaml.core.xml.config.XMLObjectProviderRegistrySupport;
import org.opensaml.saml.saml2.core.Response;
import org.opensaml.saml.saml2.core.Status;
import org.opensaml.saml.saml2.core.StatusCode;
import org.opensaml.saml.saml2.core.impl.ResponseMarshaller;
import org.opensaml.saml.saml2.core.impl.ResponseUnmarshaller;
import org.opensaml.saml.security.impl.SAMLSignatureProfileValidator;
import org.opensaml.security.SecurityException;
import org.opensaml.security.credential.Credential;
import org.opensaml.security.x509.X509Credential;
import org.opensaml.xmlsec.config.impl.JavaCryptoValidationInitializer;
import org.opensaml.xmlsec.signature.Signature;
import org.opensaml.xmlsec.signature.support.SignatureValidator;
import org.w3c.dom.Element;

import javax.xml.namespace.QName;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.parsers.ParserConfigurationException;

public class SamlResponseParser {

    public static void main(String[] args) {
        try {
            // 初始化OpenSAML配置
            InitializationService.initialize();

            // 读取SAML响应字符串
            String samlResponseString = "...";

            // 将SAML响应字符串转换为DOM元素
            DocumentBuilderFactory documentBuilderFactory = DocumentBuilderFactory.newInstance();
            documentBuilderFactory.setNamespaceAware(true);
            Element element = documentBuilderFactory.newDocumentBuilder().parse(new ByteArrayInputStream(samlResponseString.getBytes())).getDocumentElement();

            // 反序列化SAML响应
            ResponseUnmarshaller responseUnmarshaller = new ResponseUnmarshaller();
            Response samlResponse = (Response) responseUnmarshaller.unmarshall(element);

            // 验证SAML响应的签名
            validateSignature(samlResponse, getSSOProviderPublicKey());

            // 检查SAML响应的状态
            if (samlResponse.getStatus() != null && samlResponse.getStatus().getStatusCode() != null) {
                Status status = samlResponse.getStatus();
                if (StatusCode.SUCCESS.equals(status.getStatusCode().getValue())) {
                    // SAML响应验证成功，可以继续处理
                    // ...
                } else {
                    // SAML响应验证失败，可以根据状态代码进行处理
                    // ...
                }
            }
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

    private static void validateSignature(Response samlResponse, Credential credential) throws SecurityException {
        if (samlResponse.getSignature() != null) {
            SAMLSignatureProfileValidator sigProfileValidator = new SAMLSignatureProfileValidator();
            sigProfileValidator.validate(samlResponse.getSignature());

            SignatureValidator.validate(samlResponse.getSignature(), (X509Credential) credential);
        }
    }

    private static Credential getSSOProviderPublicKey() {
        // 获取SSO提供商的公钥
        // 返回一个X509Credential对象，包含SSO提供商的公钥证书和密钥对
        // ...
        return null;
    }
}

请注意，示例代码假设您已经获得了SSO提供商的公钥，并且您知道如何将其转换为OpenSAML所需的X509Credential对象。

希望这可以帮助您解析SAML响应并从中提取所需的信息。请根据实际情况进行调整和修改。