Question

I’m generating some xml files that needs to conform to an xsd file that was given to me. How should I verify they conform?

Answer 1

The Java runtime library supports validation. Last time I checked this was the Apache Xerces parser under the covers. You should probably use a javax.xml.validation.Validator.

import javax.xml.XMLConstants; import javax.xml.transform.Source; import javax.xml.transform.stream.StreamSource; import javax.xml.validation.*; import java.net.URL; import org.xml.sax.SAXException; //import java.io.File; // if you use File import java.io.IOException; ... URL schemaFile = new URL('http://host:port/filename.xsd'); // webapp example xsd:  // URL schemaFile = new URL('http://java.sun.com/xml/ns/j2ee/web-app_2_4.xsd'); // local file example: // File schemaFile = new File('/location/to/localfile.xsd'); // etc. Source xmlFile = new StreamSource(new File('web.xml')); SchemaFactory schemaFactory = SchemaFactory     .newInstance(XMLConstants.W3C_XML_SCHEMA_NS_URI); try {   Schema schema = schemaFactory.newSchema(schemaFile);   Validator validator = schema.newValidator();   validator.validate(xmlFile);   System.out.println(xmlFile.getSystemId() + ' is valid'); } catch (SAXException e) {   System.out.println(xmlFile.getSystemId() + ' is NOT valid reason:' + e); } catch (IOException e) {} 

The schema factory constant is the string http://www.w3.org/2001/XMLSchema which defines XSDs. The above code validates a WAR deployment descriptor against the URL http://java.sun.com/xml/ns/j2ee/web-app_2_4.xsd but you could just as easily validate against a local file.

You should not use the DOMParser to validate a document (unless your goal is to create a document object model anyway). This will start creating DOM objects as it parses the document – wasteful if you aren’t going to use them.