Fenetre.java

import java.awt.BorderLayout;
import java.io.BufferedReader;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileReader;
import java.io.FileWriter;
import java.io.IOException;

import javax.swing.JEditorPane;
import javax.swing.JFrame;
import javax.swing.JScrollPane;
import javax.swing.JTabbedPane;
import javax.swing.event.ChangeEvent;
import javax.swing.event.ChangeListener;
import javax.swing.text.html.HTMLEditorKit;

//CTRL + SHIFT + O pour générer les imports nécessaires

public class Fenetre extends JFrame {
  private JEditorPane editorPane, apercu;
  private JTabbedPane onglet = new JTabbedPane();
   
  public Fenetre(){
    this.setSize(600, 400);
    this.setTitle("Conteneur éditable");
    this.setLocationRelativeTo(null);
   // this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

    editorPane = new JEditorPane();
    
    BufferedReader in = null;
	try {
		in = new BufferedReader(new FileReader("test.html"));
	} catch (FileNotFoundException e) {
		e.printStackTrace();
	}
	String line;
	String s = "";
	try {
		while ((line = in.readLine()) != null)
		{
		  // Afficher le contenu du fichier
			s += line + "\n" ;
			//System.out.println(line);
			//System.out.println(s);
		}
	} catch (IOException e) {
		// TODO Auto-generated catch block
		e.printStackTrace();
	}
	try {
		in.close();
	} catch (IOException e) {
		// TODO Auto-generated catch block
		e.printStackTrace();
	}
    
    
    editorPane.setText(s);
      
    apercu = new JEditorPane();
    apercu.setEditable(false);
      
    onglet.addTab("Editeur HTML", new JScrollPane(editorPane));
    onglet.addTab("Aperçu", new JScrollPane(apercu));
    onglet.addChangeListener(new ChangeListener(){

      public void stateChanged(ChangeEvent e) {            
        FileWriter fw = null;            
        try {
          fw = new FileWriter(new File("tmp.html"));
          fw.write(editorPane.getText());
          fw.close();
        } catch (FileNotFoundException e1) {
          e1.printStackTrace();
        } catch (IOException e1) {
          e1.printStackTrace();
        }
        try {
          File file = new File("tmp.html");
          apercu.setEditorKit(new HTMLEditorKit());               
          apercu.setPage(file.toURL());
        } catch (IOException e1) {
          e1.printStackTrace();
        }             
      }            
    });
      
    this.getContentPane().add(onglet, BorderLayout.CENTER);
    this.setVisible(true);
  }
   
  public static void main(String[] args){
    Fenetre fen = new Fenetre();
  }   
}