如何使用 JAXB 针对模式验证 XML?

I am working with XML and JAXB as I am unmarshalling and marshalling the XML into Java objects and vice versa. Now I am trying to validate our XML against our schema(test.xsd). Suppose if any required field is missing in my XML, then I would like to know which field is missing after validating the XML against schema test.xsd.

public void unmarshal(final InputStream is) {
    final XMLInputFactory factory = XMLInputFactory.newInstance();
    final XMLStreamReader reader = factory.createXMLStreamReader(is);

    Object req = unmarshaller.unmarshal(reader);

    // how would I validate here?
}

我将如何根据 test.xsd 架构验证我的 XML.我的 test.xsd 架构路径是 -

Schema schema = factorySchema.newSchema(new File("C:\workspace\one\two\three\src\main\java\com\package\serv\ap\versionOne\test.xsd"));