notepad.java

包含多个java程序

//NotePad.java
import java.io.*;
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;

/**
 * Simple notepad application
 * @author  WANG Junchuan
 * @version 1.0 05/24/03
 */
 public class NotePad extends JFrame implements ActionListener
{
	public static void main(String args[]) {
		NotePad mainFrame = new NotePad();
	}

	private String		filename = null;
	private JTextArea	editor = new JTextArea();

	private JMenuItem	newf = new JMenuItem("New"), openf = new JMenuItem("Open"), 
						savef = new JMenuItem("Save"),saveAs = new JMenuItem("Save As");
	
	public NotePad() {
		super("NotePad--New");
		Container	c = getContentPane();
		JMenuBar	mainMenuBar = new JMenuBar();
		JMenu		fileMenu = new JMenu("File");
		JMenuItem	fileItems[] = {newf, openf, savef, saveAs};

		for(int i=0; i<fileItems.length; ++i) {
			fileMenu.add(fileItems[i]);
			fileItems[i].addActionListener(this);
		}
		mainMenuBar.add(fileMenu);
		setJMenuBar(mainMenuBar);
		c.add(new JScrollPane(editor), BorderLayout.CENTER);

		setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
		setSize(640, 480);
		setVisible(true);
	}

	public void actionPerformed(ActionEvent e) {
		Object src = e.getSource();
		if (src == newf) {
			editor.setText("");
			filename = null;
			setTitle("NotePad--New");
		}
		else if (src == openf) {
			if(showDlg(JFileChooser.OPEN_DIALOG) != false)
				read();
		}
		else if (src == savef) {
			if (filename!=null || showDlg(JFileChooser.SAVE_DIALOG)!=false)
				save();
		}
		else if (src == saveAs) {
			if (showDlg(JFileChooser.SAVE_DIALOG) != false)
				save();
		}
	}

    /**
	 * Read text from filename to editor
     */
	private void	read() {
		String line;
		editor.setText("");
		try {
			BufferedReader in = new BufferedReader(new FileReader(filename));
			while( (line=in.readLine()) != null ) {
				editor.append(line);
				editor.append("\n"); 
			}
			in.close();
		} catch (Exception e){}
	}

    /**
	 * Save text of editor to filename 
     */
	private void	save() {
		String text = editor.getText();
		try {
			BufferedWriter out = new BufferedWriter(new FileWriter(filename));
			out.write(text,0,text.length());
			out.close();
		} catch (Exception e){}
	}

    /**
	 * Show a choosing file dialog
	 * @param dlgType the type of dialog to be displayed
     */
	private boolean	showDlg(int dlgType) {
		JFileChooser chooser = new JFileChooser();

		chooser.setDialogType(dlgType);
		if((chooser.showDialog(null,null) != JFileChooser.APPROVE_OPTION))
			return	false;
		filename = chooser.getSelectedFile().getPath();
		setTitle("NotePad--" + filename);			
		return	true;
	}
}