Java Tips - How to create XML validator from XML schema

In order to check XML data for validity we have to prepare its schema XSD-file. This file will be loaded by a JAXP package to a Schema objects instance. Then we'll use Schema to produce Validator which can then be used to validate any document with type defined in outr schema.


import javax.xml.transform.stream.StreamSource;

import javax.xml.validation.Schema;

import javax.xml.validation.SchemaFactory;

import javax.xml.validation.Validator;



import org.xml.sax.SAXException;



/**

 * A sample application which shows how to perform a

 * XML document validation.

 */



public class Test {

  public static void main(String[] args) {

    try {

      // define the type of schema - we use W3C:

      String schemaLang = "http://www.w3.org/2001/XMLSchema";



      // get validation driver:

      SchemaFactory factory = SchemaFactory.newInstance(schemaLang);



      // create schema by reading it from an XSD file:

      Schema schema = factory.newSchema(new StreamSource("sample.xsd"));

      Validator validator = schema.newValidator();



      // at last perform validation:

      validator.validate(new StreamSource("sample.xml"));



    }catch (SAXException ex) {

      // we are here if the document is not valid:

      // ... process validation error...

    } catch (Exception ex) {

      ex.printStackTrace();

    }

  }

}

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