XML Schema (XSD) Validation using SAXParser

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<< XML Schema Tutorials - Herong's Tutorial Examples

This section describes a tutorial example on how to the Xerces2 SAXParser class to validate an XML document assigned with an XSD file.

Note that tutorial examples given in this section were taken in 2002 using JDK 1.4 and Xerces-J 2.3. But the example Java program can still run using JDK 1.6 and Xerces2 2.9.1

Xerces-J package can also be loaded by the SAXParserFactory.newInstance() method. Here is my SAXValidator.java:

/**
 * SAXValidator.java
 * Copyright (c) 2002 by Dr. Herong Yang. All rights reserved.
 */
import java.io.File;
import java.io.IOException;
import javax.xml.parsers.SAXParserFactory;
import javax.xml.parsers.SAXParser;
import javax.xml.parsers.ParserConfigurationException;
import org.xml.sax.Attributes;
import org.xml.sax.SAXException;
import org.xml.sax.SAXParseException;
import org.xml.sax.helpers.DefaultHandler;
class SAXValidator {
   public static void main(String[] args) {
      String schemaFeature 
         = "http://apache.org/xml/features/validation/schema";
      try {
      	 File x = new File(args[0]);
         SAXParserFactory f = SAXParserFactory.newInstance();
         System.out.println(f.toString());
         f.setValidating(true);
         f.setFeature(schemaFeature,true);
         SAXParser p = f.newSAXParser();
         System.out.println(p.toString());
         DefaultHandler h = new MyErrorHandler();
         p.parse(x,h);
      } catch (ParserConfigurationException e) {
         System.out.println(e.toString()); 
      } catch (SAXException e) {
         System.out.println(e.toString()); 
      } catch (IOException e) {
         System.out.println(e.toString()); 
      }
   }
   private static class MyErrorHandler extends DefaultHandler {
      public void warning(SAXParseException e) throws SAXException {
         System.out.println("Warning: "); 
         printInfo(e);
      }
      public void error(SAXParseException e) throws SAXException {
         System.out.println("Error: "); 
         printInfo(e);
      }
      public void fatalError(SAXParseException e) throws SAXException {
         System.out.println("Fattal error: "); 
         printInfo(e);
      }
      private void printInfo(SAXParseException e) {
      	 System.out.println("   Public ID: "+e.getPublicId());
      	 System.out.println("   System ID: "+e.getSystemId());
      	 System.out.println("   Line number: "+e.getLineNumber());
      	 System.out.println("   Column number: "+e.getColumnNumber());
      	 System.out.println("   Message: "+e.getMessage());
      }
   }
}

Note that the schema feature is set to the SAXParserFactory object, not to the SAXParser object.

Now if you run the program with:

java -cp . dictrionary_invalid_xsd.xml

You will get:

org.apache.crimson.jaxp.SAXParserFactoryImpl@1004901
org.xml.sax.SAXNotRecognizedException: 
   Feature: http://apache.org/xml/features/validation/schema

Note that the "crimson" implementation was loaded from the J2SDK library, and it doesn't support XSD validation.

But if you run the program with:

java -cp .;\local\xerces-2_3_0\xercesImpl.jar dictrionary_invalid_xsd.xml

you will get:

org.apache.xerces.jaxp.SAXParserFactoryImpl@f72617
org.apache.xerces.jaxp.SAXParserImpl@173831b

... Same error messages as shown in the previous section ...

Note that the "xerces" implementation was loaded, and XSD validation was performed.

Sections in This Chapter

Installing Xerces2 Java Parser

Testing Examples of XSD File and XML File

XML Schema (XSD) Validation using XMLReader

XML Schema (XSD) Validation using SAXParser