第十四周课程总结&实验报告（简单记事本的实现）

package demo6;

import javax.swing.*;

import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.InputEvent;
import java.awt.event.KeyEvent;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;

public class Notepad implements ActionListener{

    JFrame frame;
    JScrollPane pan;
    JMenu menufile;
    JMenuBar jmenubar;
    JMenuItem newitem, openitem, saveitem, closeitem;
    JTextArea area;
    File file;

    public Notepad(){
            frame=new JFrame("LY");
            menufile=new JMenu("文件");
            jmenubar=new JMenuBar();
            newitem=new JMenuItem("新建(N)");
            openitem=new JMenuItem("打开(O)");
            saveitem=new JMenuItem("另保存(S)");
            closeitem=new JMenuItem("退出(X)");
            pan=new JScrollPane(pan,JScrollPane.VERTICAL_SCROLLBAR_ALWAYS,JScrollPane.HORIZONTAL_SCROLLBAR_AS_NEEDED);
            
            newitem.setMnemonic(KeyEvent.VK_N);
            openitem.setMnemonic(KeyEvent.VK_O);
            saveitem.setMnemonic(KeyEvent.VK_S);
            closeitem.setMnemonic(KeyEvent.VK_X);
            
            newitem.setAccelerator(KeyStroke.getKeyStroke(KeyEvent.VK_N,InputEvent.ALT_DOWN_MASK));
            openitem.setAccelerator(KeyStroke.getKeyStroke(KeyEvent.VK_O,InputEvent.ALT_DOWN_MASK));
            saveitem.setAccelerator(KeyStroke.getKeyStroke(KeyEvent.VK_S,InputEvent.ALT_DOWN_MASK));
            closeitem.setAccelerator(KeyStroke.getKeyStroke(KeyEvent.VK_X,InputEvent.ALT_DOWN_MASK));
            
            newitem.addActionListener(this);
            openitem.addActionListener(this);
            saveitem.addActionListener(this);
            closeitem.addActionListener(this);
            
            jmenubar.add(menufile);
            menufile.add(newitem);
            menufile.add(openitem);
            menufile.add(saveitem);
            menufile.add(closeitem);
            frame.add(pan);
            frame.setJMenuBar(jmenubar);
            frame.setVisible(true);
            frame.setSize(400,300);
            
            
            
        }

    public void actionPerformed(ActionEvent event) {
        Object ob = event.getSource();
        if (ob instanceof JMenuItem) {
            JMenuItem item = (JMenuItem) ob;
            if (item == newitem) {
                new Notepad();
            } else if (item == openitem) {
                JFileChooser ch = new JFileChooser();
                ch.showOpenDialog(null);
                file = ch.getSelectedFile();
                try {
                    FileInputStream fis = new FileInputStream(file);
                    byte[] b = new byte[fis.available()];
                    fis.read(b);
                    area.append(new String(b));
                    fis.close();
                } catch (FileNotFoundException e) {
                    e.printStackTrace();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            } else if (item == saveitem) {
                JFileChooser ch = new JFileChooser();
                ch.showSaveDialog(null);
                file = ch.getSelectedFile();
                if (!file.exists()) {
                    try {
                        file.createNewFile();
                    } catch (IOException e) {
                        e.printStackTrace();
                    }

                }
            } else if (item == closeitem) {
                System.exit(0);
            }
        }
    }

}