XML Simple Editor

Có bạn nhở tôi viết 1 bài dùng SAX đọc file xml để tạo menu động. Trong app đó lại dùng SA để hiển thị XML dạng tree, app cho phép đọc file,.. Tốn thời gian 1 chút nhưng tôi làm 1 bài.
Class SAXMenuDemo

  package vovanhai.wordpress.com;

import java.awt.BorderLayout;
import java.awt.Dimension;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileWriter;

import javax.swing.JEditorPane;
import javax.swing.JFileChooser;
import javax.swing.JFrame;
import javax.swing.JMenu;
import javax.swing.JMenuBar;
import javax.swing.JMenuItem;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JTree;
import javax.swing.filechooser.FileFilter;
import javax.swing.tree.DefaultMutableTreeNode;
import javax.swing.tree.DefaultTreeModel;
import javax.xml.parsers.SAXParser;
import javax.xml.parsers.SAXParserFactory;

import org.xml.sax.Attributes;
import org.xml.sax.ContentHandler;
import org.xml.sax.ErrorHandler;
import org.xml.sax.InputSource;
import org.xml.sax.SAXException;
import org.xml.sax.XMLReader;
import org.xml.sax.helpers.DefaultHandler;

/**
 * dùng SAX dọc XML sau đó tạo Menu
 * @author VoVanHai
 *
 */
public class SAXMenuDemo extends JFrame implements ActionListener{
	private JMenuBar menubar;
	private JEditorPane epContent;
	private JTree tree;
	private DefaultTreeModel treemodel;
	private DefaultMutableTreeNode root;
	public SAXMenuDemo() throws Exception{
		this.setTitle("http://vovanhai.wordpress.com");
		setExtendedState(MAXIMIZED_BOTH);
		setDefaultCloseOperation(EXIT_ON_CLOSE);
		this.setJMenuBar(menubar=new JMenuBar());
		createMenuFromXMLFile("menu.xml");
		this.add(new JScrollPane(epContent=new JEditorPane()));
		treemodel=new DefaultTreeModel(root=new DefaultMutableTreeNode("Root"));
		JPanel pane=new JPanel(new BorderLayout());
		pane.add(new JScrollPane(tree=new JTree(treemodel)));
		pane.setPreferredSize(new Dimension(300, 300));
		this.add(pane,BorderLayout.WEST);
	}

	private void createMenuFromXMLFile(String xmlFilePath) throws Exception{
		SAXParserFactory spf=SAXParserFactory.newInstance();
		SAXParser parser=spf.newSAXParser();
		parser.parse(xmlFilePath, new MyHandler(this));
	}
	@Override
	public void actionPerformed(ActionEvent e) {
		String action=e.getActionCommand();
		if(action.equalsIgnoreCase("Open")){
			JFileChooser fc=new JFileChooser();
			fc.setFileFilter(new FileFilter() {
				@Override
				public String getDescription() {
					return "XML files (*.xml)";
				}
				@Override
				public boolean accept(File f) {
					return f.isDirectory()||f.getName().endsWith(".xml");
				}
			});
			if(fc.showOpenDialog(null)==JFileChooser.APPROVE_OPTION){
				File file=fc.getSelectedFile();
				try {
					epContent.read(new FileInputStream(file), null);
					buildTree(file);
				} catch (Exception e1) {
					//e1.printStackTrace();
				} 
				finally{
					tree.expandRow(4);
					tree.updateUI();
				}
			}
		}
		else if(action.equalsIgnoreCase("Save")){
			JFileChooser fc=new JFileChooser();
			fc.setFileFilter(new FileFilter() {
				@Override
				public String getDescription() {
					return "XML files (*.xml)";
				}
				@Override
				public boolean accept(File f) {
					return f.isDirectory()||f.getName().endsWith(".xml");
				}
			});
			if(fc.showSaveDialog(null)==JFileChooser.APPROVE_OPTION){
				File file=fc.getSelectedFile();
				try {
					epContent.write(new FileWriter(file));
				} catch (Exception e1) {
					e1.printStackTrace();
				}
			}
		}
		else if(action.equalsIgnoreCase("Exit")){
			System.exit(1);
		}
		else if(action.equalsIgnoreCase("Cut")){
			epContent.cut();
		}
		else if(action.equalsIgnoreCase("Copy")){
			epContent.copy();
		}
		else if(action.equalsIgnoreCase("Paste")){
			epContent.paste();
		}
	}

	private void buildTree(File xmlfile) throws Exception{
		SAXParserFactory spf=SAXParserFactory.newInstance();
		SAXParser parser=spf.newSAXParser();
		
		XMLReader reader = parser.getXMLReader();
		ContentHandler jTreeContentHandler = 
			new JTreeContentHandler(treemodel, root);
		ErrorHandler jTreeErrorHandler = new JTreeErrorHandler();
		reader.setContentHandler(jTreeContentHandler);
		reader.setErrorHandler(jTreeErrorHandler);
		// Parse
		InputSource inputSource = new InputSource(xmlfile.getAbsolutePath());
		reader.parse(inputSource);
	}

	class MyHandler extends DefaultHandler{
		JMenu parent;
		ActionListener frm;
		public MyHandler(ActionListener frm) {
			this.frm=frm;
		}
		@Override
		public void startElement(String uri, String localName, String qName,
				Attributes attributes) throws SAXException {
			if(qName.equals("menu")){
				String name=attributes.getValue(0);
				parent=new JMenu(name);
				menubar.add(parent);
			}
		}
		@Override
		public void characters(char[] ch, int start, int length)
		throws SAXException {
			String name=new String(ch,start,length).trim();
			if(parent!=null && !name.trim().equals(""))
				addMenu(parent,name,frm);
		}
		void addMenu(JMenu menu,String text,ActionListener parent){
			JMenuItem item=new JMenuItem(text);
			menu.add(item);
			item.addActionListener(parent);
			parent=null;
		}
	}
	public static void main(String[] args) throws Exception{
		new SAXMenuDemo().setVisible(true);
	}
}

Lớp JTreeContentHandler.java để parse xml file sau đó tạo tree

package vovanhai.wordpress.com;

import java.util.HashMap;
import java.util.Iterator;
import java.util.Map;

import javax.swing.tree.DefaultMutableTreeNode;
import javax.swing.tree.DefaultTreeModel;

import org.xml.sax.Attributes;
import org.xml.sax.SAXException;
import org.xml.sax.helpers.DefaultHandler;

class JTreeContentHandler extends DefaultHandler{
	private Map<String, String> namespaceMappings;
	private DefaultMutableTreeNode current;

	public JTreeContentHandler(DefaultTreeModel treeModel, 
			DefaultMutableTreeNode base) {
		this.current = base;
		this.namespaceMappings = new HashMap<String, String>();
	}

	public void processingInstruction(String target, String data)
	throws SAXException {
		DefaultMutableTreeNode pi = 
			new DefaultMutableTreeNode("PI (target = '" + target +
					"', data = '" + data + "')");
		current.add(pi);
	}
	public void startPrefixMapping(String prefix, String uri) {
		namespaceMappings.put(uri, prefix);
	}

	public void endPrefixMapping(String prefix) {
		for (Iterator<String> i = namespaceMappings.keySet().iterator(); 
		i.hasNext(); ) {

			String uri = (String)i.next();
			String thisPrefix = (String)namespaceMappings.get(uri);
			if (prefix.equals(thisPrefix)) {
				namespaceMappings.remove(uri);
				break;
			}
		}
	}

	public void startElement(String namespaceURI, String localName,
			String qName, Attributes atts)
	throws SAXException {
		DefaultMutableTreeNode element = 
			new DefaultMutableTreeNode("Element: " + qName);
		current.add(element);
		current = element;

		// Determine namespace
		if (namespaceURI.length() > 0) {
			String prefix = 
				(String)namespaceMappings.get(namespaceURI);
			if (prefix.equals("")) {
				prefix = "[None]";
			}
			DefaultMutableTreeNode namespace =
				new DefaultMutableTreeNode("Namespace: prefix = '" +
						prefix + "', URI = '" + namespaceURI + "'");
			current.add(namespace);
		}

		// Process attributes
		for (int i=0; i<atts.getLength(); i++) {
			DefaultMutableTreeNode attribute =
				new DefaultMutableTreeNode("Attribute (name = '" +
						atts.getLocalName(i) + 
						"', value = '" +
						atts.getValue(i) + "')");
			String attURI = atts.getURI(i);
			if (attURI.length() > 0) {
				String attPrefix = 
					(String)namespaceMappings.get(namespaceURI);
				if (attPrefix.equals("")) {
					attPrefix = "[None]";
				}
				DefaultMutableTreeNode attNamespace =
					new DefaultMutableTreeNode("Namespace: prefix = '" +
							attPrefix + "', URI = '" + attURI + "'");
				attribute.add(attNamespace);            
			}
			current.add(attribute);
		}
	}


	public void endElement(String namespaceURI, String localName,
			String qName)
	throws SAXException {
		current = (DefaultMutableTreeNode)current.getParent();
	}

	public void characters(char[] ch, int start, int length)
	throws SAXException {
		String s = new String(ch, start, length);
		if(!s.trim().equals("")){
			DefaultMutableTreeNode data =
				new DefaultMutableTreeNode("Character Data: '" + s + "'");
			current.add(data);
		}
	}

	public void skippedEntity(String name) throws SAXException {
		DefaultMutableTreeNode skipped =
			new DefaultMutableTreeNode("Skipped Entity: '" + name + "'");
		current.add(skipped);
	}
}

Lớp JTreeErrorHandler.java thông báo lỗi trong quá trình parse xml document

package vovanhai.wordpress.com;
import javax.swing.JOptionPane;
import org.xml.sax.ErrorHandler;
import org.xml.sax.SAXException;
import org.xml.sax.SAXParseException;

class JTreeErrorHandler implements ErrorHandler {
    public void warning(SAXParseException exception)
        throws SAXException {
        String s=("**Parsing Warning**\n" +
                           "  Line:" +exception.getLineNumber() + "\n" +
                           "  URI:" +exception.getSystemId() + "\n" +
                           "  Message: " +exception.getMessage());        
        JOptionPane.showMessageDialog(null, s,"Thông báo",JOptionPane.ERROR_MESSAGE);
    }

    public void error(SAXParseException exception)
        throws SAXException {
       String s=("**Parsing Error**\n" +
                           "  Line:" +exception.getLineNumber() + "\n" +
                           "  URI:" +exception.getSystemId() + "\n" +
                           "  Message:" +exception.getMessage());
       JOptionPane.showMessageDialog(null, s,"Thông báo",JOptionPane.ERROR_MESSAGE);
    }

    public void fatalError(SAXParseException exception)
        throws SAXException {
    
        String s=("**Parsing Fatal Error**\n" +
                           "  Line:" + exception.getLineNumber() + "\n" +
                           "  URI:" + exception.getSystemId() + "\n" +
                           "  Message:" +exception.getMessage());        
        JOptionPane.showMessageDialog(null, s,"Thông báo",JOptionPane.ERROR_MESSAGE);
    }
}

File menu.xml là file có cấu trúc menu. Bạn thêm 1 element menu là có thêm 1 menu, 1 item element là có thêm sub menu.

<?xml version="1.0" encoding="UTF-8"?>
<menus>
	<menu name="File">
		<item>Open</item>
		<item>Save</item>
		<item>Exit</item>
	</menu>
	<menu name="Edit">
		<item>Cut</item>
		<item>Copy</item>
		<item>Paste</item>
	</menu>
</menus>

OK. Chạy! Kết quả như sau:

Chúc thành công