Java で XML ファイルを XSD スキーマに対して検証するにはどうすればよいですか?

import javax.xml.transform.Source;
import javax.xml.transform.stream.StreamSource;
import javax.xml.validation.Schema;
import javax.xml.validation.SchemaFactory;
import javax.xml.validation.Validator;
import java.net.URL;

// Instantiate the schema factory
SchemaFactory schemaFactory = SchemaFactory.newInstance(XMLConstants.W3C_XML_SCHEMA_NS_URI);

// Load the XSD schema from a URL
URL schemaFile = new URL("http://host:port/filename.xsd");
Schema schema = schemaFactory.newSchema(schemaFile);

// Load the XML file to be validated
Source xmlFile = new StreamSource(new File("web.xml"));

// Create a new validator
Validator validator = schema.newValidator();

try {
  // Validate the XML document
  validator.validate(xmlFile);
  System.out.println(xmlFile.getSystemId() + " is valid");
} catch (SAXException e) {
  System.out.println(xmlFile.getSystemId() + " is NOT valid reason:" + e);
}