[SAX] Aficher un document xml sous forme d'arbre

Un petit exemple d'affichage de XML dans un JTree avec StAX :
Code:
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import java.awt.Component;
import java.awt.Toolkit;
import java.io.File;
import java.io.IOException;
import java.io.InputStream;
import java.nio.file.Files;
import java.nio.file.Path;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collections;
import java.util.List;
import java.util.Optional;
import java.util.stream.StreamSupport;
 
import javax.swing.JFileChooser;
import javax.swing.JFrame;
import javax.swing.JMenu;
import javax.swing.JMenuBar;
import javax.swing.JMenuItem;
import javax.swing.JOptionPane;
import javax.swing.JScrollPane;
import javax.swing.JSplitPane;
import javax.swing.JTextPane;
import javax.swing.JTree;
import javax.swing.filechooser.FileFilter;
import javax.swing.tree.DefaultMutableTreeNode;
import javax.swing.tree.DefaultTreeModel;
import javax.swing.tree.TreeNode;
import javax.swing.tree.TreePath;
import javax.swing.tree.TreeSelectionModel;
import javax.xml.namespace.QName;
import javax.xml.stream.XMLInputFactory;
import javax.xml.stream.XMLStreamException;
import javax.xml.stream.XMLStreamReader;
import javax.xml.stream.events.XMLEvent;
 
public class XMLStAXDemo {
 
	public static void main(String[] args) {
 
		JFrame frame = new JFrame("XML/StAX/JTree");
		frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
 
		JTree jtree = new JTree(new DefaultTreeModel(new DefaultMutableTreeNode()));
		jtree.setRootVisible(false);
		jtree.getSelectionModel().setSelectionMode(TreeSelectionModel.SINGLE_TREE_SELECTION);
 
		JTextPane textpane = new JTextPane();
		textpane.setEditable(false);
 
		JSplitPane panel = new JSplitPane();
		panel.setLeftComponent(new JScrollPane(jtree));
		panel.setRightComponent(new JScrollPane(textpane));
 
		jtree.addTreeSelectionListener(e-> treeSelection(jtree, textpane));
 
		frame.add(panel);
 
		JMenuBar menubar = new JMenuBar();
		JMenu menu = new JMenu("Fichier");
		JMenuItem menuItem = new JMenuItem("Charger");
		menuItem.addActionListener(e-> load(frame, jtree));
		menu.add(menuItem);
		menubar.add(menu);
		frame.setJMenuBar(menubar);
 
		frame.setSize(Toolkit.getDefaultToolkit().getScreenSize());
		frame.setLocationRelativeTo(null);
		frame.setVisible(true);
 
		panel.setDividerLocation(0.33d);
 
	}
 
	private static void treeSelection(JTree tree, JTextPane textpane) {
		TreePath path = tree.getSelectionPath();
		if ( path==null ) {
			textpane.setText("");
		}
		else {
			DefaultMutableTreeNode treenode = (DefaultMutableTreeNode) path.getLastPathComponent();
			Node node = (Node) treenode.getUserObject();
			if ( node.isText() ) {
				textpane.setText(node.getText());
			}
			else {
				textpane.setText("");
			}
		}
	}
 
	private static void load(Component parent, JTree jtree) {
 
		Path path = chooseFile(parent);
 
		if ( path!=null ) {
			try {
				TreeNode root = new XMLStAXDemo().load(path);
				jtree.setModel(new DefaultTreeModel(root));
			} catch (XMLStreamException | IOException e) {
				JOptionPane.showMessageDialog(jtree, "Impossible de lire le fichier", "Erreur", JOptionPane.ERROR_MESSAGE);
			}
		}
 
	}
 
	public TreeNode load(Path path) throws XMLStreamException, IOException {
 
		try( InputStream inputStream = Files.newInputStream(path) ) {
 
			XMLInputFactory xmlInputFactory = XMLInputFactory.newInstance();
			XMLStreamReader xmlReader = xmlInputFactory.createXMLStreamReader(path.getFileName().toString(), inputStream);
 
            try {
 
        		DefaultMutableTreeNode root = null;
        		DefaultMutableTreeNode current = null;
            	while(xmlReader.hasNext()) {
                    switch( xmlReader.next() ) {
                    	case XMLEvent.START_ELEMENT:
                     		DefaultMutableTreeNode newNode = new DefaultMutableTreeNode( new Node(xmlReader.getName()));
                    		if ( root == null ) {
                    			root = newNode;
                    		}
                    		if ( current!=null ) {
                    			current.add(newNode);
                    		}
                    		current=newNode;
                    		break;
                    	case XMLEvent.END_ELEMENT:
                    		current = (DefaultMutableTreeNode) current.getParent();
                    		break;
                    	case XMLEvent.CHARACTERS:
                                // FIXME: gestion preservespace
                    		String text=xmlReader.getText().trim();
                    		if ( !text.isEmpty() ) {
                    			Node childText = getChildText(current);
                    			if ( childText!=null ) {
                    				childText.append(text);
                    			}
                    			else {
                    				current.add(new DefaultMutableTreeNode( new Node(text) ));
                    			}
                    		}
                    		break;
                    }
            	}
 
            	return root;
 
            }
            finally {
            	xmlReader.close();
            }
 
		}
 
	}
 
	private Node getChildText(DefaultMutableTreeNode current) {
		int index=current.getChildCount()-1;
		if ( index>=0 ) {
			DefaultMutableTreeNode treeNode = (DefaultMutableTreeNode) current.getChildAt(index);
			Node node = (Node) treeNode.getUserObject();
			if ( node.isText() ) {
				return node;
			}
		}
		return null;
	}
 
	private static Path chooseFile(Component parent) {
		JFileChooser filechooser = new JFileChooser();
		filechooser.setDialogTitle("Choisir fichier");
		filechooser.setFileSelectionMode(JFileChooser.FILES_ONLY);
		filechooser.setMultiSelectionEnabled(false);
		filechooser.setFileFilter(new FileFilter() {
 
			@Override
			public String getDescription() {
				return "Fichiers XML (*.xml)";
			}
 
			@Override
			public boolean accept(File f) {
				return f.getName().endsWith(".xml");
			}
		});
		if( filechooser.showOpenDialog(parent)==JFileChooser.APPROVE_OPTION ) {
			return filechooser.getSelectedFile().toPath();
		}
		return null;
	}
 
	public static class Node {
 
		private final QName qname;
		private String text;
 
		public Node(QName qname) {
			this.qname=qname;
			this.text=qname.getLocalPart();
		}
 
		public void append(String text) {
			Arrays.asList(text.split("\n")).stream().map(t->t.trim()).forEach(t-> this.text= (this.text==null?t:this.text + "\n"+ t));
		}
 
		public Node(String text) {
			this.qname=null;
			append(text);
		}
 
		public QName getQname() {
			return qname;
		}
 
		public String getText() {
			return text.trim();
		}
 
		public boolean isText() {
			return qname==null;
		}
 
		@Override
		public String toString() {
			if ( text.contains("\n") ) {
				return text.substring(0, text.indexOf("\n")) + "\u2026";
			}
			return  text;
		}
 
	}
 
}