Java Sax Schema Validation Example
In this article, i am going to use the Swing for the UI purpose and for the XML validation against its schema i will use DOM parser as well as SAX Parser. previously we have already seen that how these parsers works in detail.
Application output will look like below snap:
How to validate using DOM Parser :
- Create instance of "DocumentBuilderFactory".
- Set validation true.
- Set two attributes for schema language and schema source in factory instance.
- Create instance of "DocumentBuilder" from factory and parse.
- Check validateUsingDOM() method in below code.
How to validate using SAX Parser:
- Create instance of "SAXParserFactory".
- Set validation true.
- Create instance of "SAXParser" from factory object.
- Set two property for schema language and schema source in parser instance and parse.
- Check validateUsingSAX() method in below code.
Complete code:
package com.g2.XML; import java.awt.Color; import java.awt.EventQueue; import java.awt.Font; import java.awt.event.ActionEvent; import java.awt.event.ActionListener; import java.io.File; import java.io.IOException; import java.io.PrintWriter; import java.io.StringWriter; import java.io.Writer; import javax.swing.AbstractAction; import javax.swing.Action; import javax.swing.JButton; import javax.swing.JFileChooser; import javax.swing.JFrame; import javax.swing.JScrollPane; import javax.swing.JTextArea; import javax.swing.JTextField; import javax.xml.parsers.DocumentBuilder; import javax.xml.parsers.DocumentBuilderFactory; import javax.xml.parsers.ParserConfigurationException; import javax.xml.parsers.SAXParser; import javax.xml.parsers.SAXParserFactory; import org.xml.sax.SAXException; import org.xml.sax.helpers.DefaultHandler; public class DOMXMLSchemaValidator { private JFrame frame; private JTextField txtXSDName; private final Action action = new SwingAction(); private JFileChooser fc = new JFileChooser(); JTextArea txtResult = new JTextArea(); private JTextField txtXMLName; private JButton btnValidateUsingDom; private JButton btnValidateUsingSax; private JButton btnDisplayActualError; private String errorMsg; private JScrollPane scrollPane; /** * Launch the application. */ public static void main(String[] args) { EventQueue.invokeLater(new Runnable() { public void run() { try { DOMXMLSchemaValidator window = new DOMXMLSchemaValidator(); window.frame.setVisible(true); } catch (Exception e) { e.printStackTrace(); } } }); } /** * Create the application. */ public DOMXMLSchemaValidator() { initialize(); } /** * Initialize the contents of the frame. */ private void initialize() { ApplicationActions btnActions = this.new ApplicationActions(); frame = new JFrame("XML Schema Validator using DOM Parser"); frame.getContentPane().setBackground( Color.LIGHT_GRAY); frame.setBounds(100, 100, 492, 300); frame.setDefaultCloseOperation( JFrame.EXIT_ON_CLOSE); frame.getContentPane().setLayout(null); JButton btnSelectXsdFile = new JButton("Select XSD File"); btnSelectXsdFile.setAction(action); btnSelectXsdFile.setBounds(327, 11, 127, 23); frame.getContentPane().add(btnSelectXsdFile); txtXSDName = new JTextField(); txtXSDName.setBounds(10, 12, 298, 23); frame.getContentPane().add(txtXSDName); txtXSDName.setColumns(10); txtXMLName = new JTextField(); txtXMLName.setColumns(10); txtXMLName.setBounds(10, 46, 298, 23); frame.getContentPane().add(txtXMLName); JButton btnSelectXmlFile = new JButton("Select XML File"); btnSelectXmlFile.addActionListener(new ActionListener() { @Override public void actionPerformed(ActionEvent arg0) { txtResult.setBackground(Color.ORANGE); int returnVal = fc.showOpenDialog(frame); if (returnVal == JFileChooser.APPROVE_OPTION) { File file = fc.getSelectedFile(); txtXMLName.setText(file.getPath()); } } }); btnSelectXmlFile.setBounds(327, 45, 127, 23); btnSelectXmlFile.addActionListener(btnActions); frame.getContentPane().add(btnSelectXmlFile); btnValidateUsingDom = new JButton("Validate Using DOM"); btnValidateUsingDom.setBounds(50, 93, 172, 23); btnValidateUsingDom.addActionListener(new ApplicationActions()); frame.getContentPane().add(btnValidateUsingDom); btnValidateUsingSax = new JButton("Validate Using SAX"); btnValidateUsingSax.setBounds(262, 93, 164, 23); frame.getContentPane().add(btnValidateUsingSax); btnValidateUsingSax.addActionListener(new ApplicationActions()); scrollPane = new JScrollPane(); scrollPane.setBounds(10, 161, 464, 112); frame.getContentPane().add(scrollPane); scrollPane.setViewportView(txtResult); txtResult.setFont(new Font("Monospaced", Font.PLAIN, 13)); txtResult.setBackground(Color.ORANGE); btnDisplayActualError = new JButton("Display Actual Error"); btnDisplayActualError.setBounds(148, 127, 154, 23); frame.getContentPane().add(btnDisplayActualError); btnDisplayActualError.setVisible(false); btnDisplayActualError.addActionListener(new ApplicationActions()); } private void validateUsingDOM() { errorMsg = ""; DocumentBuilderFactory DF = DocumentBuilderFactory.newInstance(); DF.setValidating(true); DF.setAttribute( "http://java.sun.com/xml/jaxp/ properties/schemaLanguage", "http://www.w3.org/2001/XMLSchema"); DF.setAttribute("http://java.sun.com/xml/jaxp/ properties/schemaSource", txtXSDName.getText()); try { DocumentBuilder DB = DF.newDocumentBuilder(); DB.parse(txtXMLName.getText()); styleTextBox(false, null); } catch (ParserConfigurationException e) { styleTextBox(true, e); } catch (SAXException e) { styleTextBox(true, e); } catch (IOException e) { styleTextBox(true, e); } catch (Exception e) { styleTextBox(true, e); } } private void styleTextBox(boolean isError, Throwable t) { if (isError) { btnDisplayActualError.setVisible(true); txtResult.setBackground(Color.RED); txtResult .setText("Document is not validated or Some error occured"); if (t != null) { getStackTrace(t); } } else { txtResult.setBackground(Color.GREEN); txtResult.setText("Validation Success..."); } } public void getStackTrace(Throwable aThrowable) { Writer result = new StringWriter(); PrintWriter printWriter = new PrintWriter(result); aThrowable.printStackTrace(printWriter); errorMsg = result.toString(); } private void validateUsingSAX() { SAXParserFactory SF = SAXParserFactory.newInstance(); SF.setValidating(true); SAXParser SP; try { SP = SF.newSAXParser(); SP.setProperty( "http://java.sun.com/xml/jaxp/ properties/schemaLanguage", "http://www.w3.org/2001/XMLSchema"); SP.setProperty( "http://java.sun.com/xml/jaxp/ properties/schemaSource", txtXSDName.getText()); SP.parse(new File(txtXMLName.getText()), new DefaultHandler()); styleTextBox(false, null); } catch (ParserConfigurationException e) { styleTextBox(true, e); } catch (SAXException e) { styleTextBox(true, e); } catch (IOException e) { styleTextBox(true, e); } catch (Exception e) { styleTextBox(true, e); } } private class SwingAction extends AbstractAction { public SwingAction() { putValue(NAME, "Select XSD File"); putValue(SHORT_DESCRIPTION, "Select XML schema file present on local disc"); } public void actionPerformed(ActionEvent e) { txtResult.setBackground(Color.ORANGE); if (e.getActionCommand().equals("Select XSD File")) { int returnVal = fc.showOpenDialog(frame); if (returnVal == JFileChooser.APPROVE_OPTION) { File file = fc.getSelectedFile(); txtXSDName.setText(file.getPath()); } } } } private class ApplicationActions implements ActionListener { @Override public void actionPerformed(ActionEvent evt) { if (evt.getActionCommand().equals("Validate Using DOM")) { if (validateControls()) { validateUsingDOM(); } } else if (evt.getActionCommand().equals("Display Actual Error")) { txtResult.setText(errorMsg); } else if (evt.getActionCommand().equals("Validate Using SAX")) { if (validateControls()) validateUsingSAX(); } } private boolean validateControls() { boolean retVal = true; if (txtXMLName.getText().trim().equals("")) { txtXMLName.setBackground(Color.RED); txtXMLName.setText("Required field"); retVal = false; } if (txtXSDName.getText().trim().equals("")) { txtXSDName.setBackground(Color.RED); txtXSDName.setText("Required field"); retVal = false; } return retVal; } } } Output:
1. Validation succeeded
2. Validation failed
Sample XSD (Schema) document:
<xsd:schema xmlns:xsd="http://www.w3.org/2001/XMLSchema"> <xsd:element name="cricket" type="CricketType" /> <xsd:complexType name="CricketType"> <xsd:sequence> <xsd:element name="team" type="TeamType" maxOccurs="unbounded" /> </xsd:sequence> </xsd:complexType> <xsd:complexType name="TeamType"> <xsd:sequence> <xsd:element name="player" type="PlayerType" maxOccurs="16" minOccurs="1" /> </xsd:sequence> <xsd:attribute name="country" type="xsd:string" use="required" /> </xsd:complexType> <xsd:complexType name="PlayerType"> <xsd:sequence> <xsd:element name="player-name" type="xsd:string" /> <xsd:element name="total-runs" type="xsd:positiveInteger" /> <xsd:element name="no-of-100s" type="xsd:positiveInteger" /> <xsd:element name="no-of-50s" type="xsd:positiveInteger" /> </xsd:sequence> </xsd:complexType> </xsd:schema>
Sample XML document:
<?xml version="1.0" encoding="utf-8"?> <cricket xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"> <team country="India"> <player> <player-name>Player1</player-name> <total-runs>10000</total-runs> <no-of-100s>30</no-of-100s> <no-of-50s>70</no-of-50s> </player> <player> <player-name>Player2</player-name> <total-runs>1000</total-runs> <no-of-100s>1</no-of-100s> <no-of-50s>3</no-of-50s> </player> <player> <player-name>Player3</player-name> <total-runs>6443</total-runs> <no-of-100s>12</no-of-100s> <no-of-50s>23</no-of-50s> </player> </Team> <team country="Australia"> <player> <player-name>Aussie Player1</player-name> <total-runs>10000</total-runs> <no-of-100s>30</no-of-100s> <no-of-50s>70</no-of-50s> </player> <player> <player-name>Aussie Player2</player-name> <total-runs>1000</total-runs> <no-of-100s>1</no-of-100s> <no-of-50s>3</no-of-50s> </player> <player> <player-name>Aussie Player3</player-name> <total-runs>6443</total-runs> <no-of-100s>12</no-of-100s> <no-of-50s>23</no-of-50s> </player> </team> </cricket>
Source: https://www.jitendrazaa.com/blog/java/validate-xml-schema-using-dom-parser-and-sax-parser-in-java-using-swing/
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