edit.java

此代码的功能是实现一个简单的文本编辑器

import java.awt.*;
import java.awt.event.*;
import java.io.*;
import javax.swing.JOptionPane;

class MyFrame extends Frame implements ActionListener
{
	final static int MAX_LEN=64*1024;
	TextArea ta;
	MenuBar mb_bar;
	Menu mm_file;
	MenuItem mi_open;
	MenuItem mi_save;
	MenuItem mi_exit;
	Menu mm_about;
	
	MyFrame()
	{
		setTitle("简易文本编辑器");
		setSize(600,400);
		setLocation(100,100);
		ta=new TextArea();
		mb_bar=new MenuBar();
		mm_file=new Menu("File");
		mi_open=new MenuItem("open");
		mi_open.addActionListener(this);
		mi_save=new MenuItem("save");
		mi_save.addActionListener(this);
		mi_exit=new MenuItem("exit");
		mi_exit.addActionListener(this);
		mm_about=new Menu("About");
		mm_about.addActionListener(this);
	 	mm_file.add(mi_open);
	  	mm_file.add(mi_save);
		mm_file.add(mi_exit);
		mb_bar.add(mm_file);
		mb_bar.add(mm_about);
		setMenuBar(mb_bar);
		addWindowListener(new WinLin());
		add(ta);
		show();
	}
	
	public void actionPerformed(ActionEvent e)
	{
		if(e.getSource()==mi_open)
		{
			FileDialog fo=new FileDialog(this,"Load File",FileDialog.LOAD);
			fo.show();
			String strFile=fo.getDirectory()+fo.getFile();
			if(strFile!=null)
			{
				setTitle(fo.getFile());
				try{
					ta.setText("");
					FileInputStream fi=new FileInputStream(strFile);
					int len;
					byte[] buf=new byte[MAX_LEN];
					len=fi.read(buf);
					ta.setText(new String(buf,0,len));
					fi.close();
				}
				catch(Exception ex)
				{
					ex.printStackTrace();
				}
			}
		}
		else if(e.getSource()==mi_save)
		{
				FileDialog fs=new FileDialog(this,"Save File",FileDialog.SAVE);
				fs.show();
				String strFile;
				strFile=fs.getDirectory()+fs.getFile();
				setTitle(fs.getFile());
				try{
				FileOutputStream fo=new FileOutputStream(strFile);	
				fo.write(ta.getText().getBytes());
				fo.close();
				}
				catch(Exception ex)
				{
					ex.printStackTrace();
				}
		}
		else if(e.getSource()==mi_exit)
		{
			System.exit(0);
		}
		else if(e.getSource()==mm_about)
		{
			JOptionPane.showMessageDialog(null,"made by zhangjiawen");
		}
	}
	
}

class WinLin extends WindowAdapter
{
		public void windowClosing(WindowEvent e)  
		{
			System.exit(0);
		}
}

class edit
{
	public static void main(String[] args)
	{
		MyFrame mf=new MyFrame();
	}	
}