notepad.java

一个java实现的记事本程序 代码简单清晰

import java.io.*;
import java.awt.*;
import java.awt.event.*;

public class NotePad implements ActionListener{
	Frame f = new Frame("记事本");
	TextArea ta = new TextArea();
	
	public NotePad(){
		MenuBar mb = new MenuBar();
		Menu m = new Menu("File");
		MenuItem mi1 = new MenuItem("open");
		MenuItem mi2 = new MenuItem("quit");
		MenuItem mi3 = new MenuItem("save");
		
		f.setMenuBar(mb);
		mb.add(m);
		m.add(mi1);
		m.add(mi3);
		m.addSeparator();
		m.add(mi2);
		
		f.add(ta);
		f.setLocation(200,200);
		f.setSize(500,600);
		f.setVisible(true);
		
		mi1.addActionListener(this);
		mi3.addActionListener(this);
	}
	
	public void actionPerformed(ActionEvent e){
		String s = e.getActionCommand();
		if(s.equals("open")){
			ta.setText("");
			this.readFile();
		}else if(s.equals("save")){
			this.saveFile();
		}
	}
	
	public void readFile(){
		try{
			FileDialog fd = new FileDialog(f,"open",FileDialog.LOAD);
			fd.setVisible(true);
			String path = fd.getDirectory();
			String file = fd.getFile();
			if(path!=null){
				FileReader fr = new FileReader(path+file);
				BufferedReader br = new BufferedReader(fr);
				String s = br.readLine();
				while(s!=null){
					ta.append(s+"\n");
					s = br.readLine();
				}
				br.close();
				fr.close();		
			}
		}catch(IOException e){
			e.printStackTrace();
		}
		
	}
	
	public void saveFile(){
		try{
			FileDialog fd = new FileDialog(f,"open",FileDialog.SAVE);
			fd.setVisible(true);
			String path = fd.getDirectory();
			String file = fd.getFile();
			if(path!=null){
				FileWriter fr = new FileWriter(path+file);
				PrintWriter pw = new PrintWriter(fr);
				pw.println(ta.getText());
				pw.close();
				fr.close();
			}
		}catch(IOException e){
			e.printStackTrace();
		}
	}
	
	public static void main(String[] args){
		new NotePad();
	}
}