Java HTML / XML How to - Do XSD validation

Question

We would like to know how to do XSD validation.
Answer

/*from  ww w  .  j  a v a  2  s .  c o  m*/
import java.io.StringReader;
import javax.xml.XMLConstants;
import javax.xml.parsers.SAXParser;
import javax.xml.parsers.SAXParserFactory;
import javax.xml.transform.Source;
import javax.xml.transform.stream.StreamSource;
import javax.xml.validation.Schema;
import javax.xml.validation.SchemaFactory;
import org.xml.sax.Attributes;
import org.xml.sax.InputSource;
import org.xml.sax.SAXException;
import org.xml.sax.SAXParseException;
import org.xml.sax.helpers.DefaultHandler;

public class Main {
  public static void main(String[] args) throws Exception {
    String xml = "<?xml version='1.0'?><test><test2></test2></test>";
    String schemaString = //
    "<?xml version='1.0'?>"//
        + "<xsd:schema xmlns:xsd='http://www.w3.org/2001/XMLSchema' elementFormDefault='unqualified' attributeFormDefault='unqualified'>"//
        + "<xsd:element name='test' type='Test'/>"//
        + "<xsd:element name='test2' type='Test2'/>"//
        + "<xsd:complexType name='Test'>"//
        + "<xsd:sequence>"//
        + "<xsd:element ref='test2' minOccurs='1' maxOccurs='unbounded'/>"//
        + "</xsd:sequence>"//
        + "</xsd:complexType>"//
        + "<xsd:simpleType name='Test2'>"//
        + "<xsd:restriction base='xsd:string'><xsd:minLength value='1'/></xsd:restriction>"//
        + "</xsd:simpleType>"//
        + "</xsd:schema>";

    Source schemaSource = new StreamSource(new StringReader(schemaString));
    Schema schema = SchemaFactory.newInstance(
        XMLConstants.W3C_XML_SCHEMA_NS_URI).newSchema(schemaSource);

    SAXParserFactory factory = SAXParserFactory.newInstance();
    factory.setNamespaceAware(true);
    factory.setSchema(schema);
    SAXParser parser = factory.newSAXParser();
    MyContentHandler handler = new MyContentHandler();
    parser.parse(new InputSource(new StringReader(xml)), handler);

  }

  static class MyContentHandler extends DefaultHandler {
    private String element = "";

    @Override
    public void startElement(String uri, String localName, String qName,
        Attributes attributes) throws SAXException {

      if (localName != null && !localName.isEmpty())
        element = localName;
      else
        element = qName;

    }

    @Override
    public void warning(SAXParseException exception) throws SAXException {
      System.out.println(element + ": " + exception.getMessage());
    }

    @Override
    public void error(SAXParseException exception) throws SAXException {
      System.out.println(element + ": " + exception.getMessage());
    }

    @Override
    public void fatalError(SAXParseException exception) throws SAXException {
      System.out.println(element + ": " + exception.getMessage());
    }

    public String getElement() {
      return element;
    }
  }
}