main.java

实现记事本功能 包括打开

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package noteofjava;

/**
 *
 * @author Administrator
 */
//package noteofjava;

import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;
import java.awt.event.WindowListener;
import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.File;
import java.io.FileReader;
import java.io.FileWriter;
import java.io.IOException;
import java.util.logging.Level;
import java.util.logging.Logger;
import javax.swing.JFileChooser;
import javax.swing.JFrame;
import javax.swing.JMenu;
import javax.swing.JMenuBar;
import javax.swing.JMenuItem;
import javax.swing.JScrollPane;
import javax.swing.JTextArea;

class Note {

    static JFrame jframe=new JFrame("记事本");
    static JMenuBar jmenubar=new JMenuBar();
    static JMenu jmenu1=new JMenu("文件");
    static JMenu jmenu2=new JMenu("编辑");
    static JMenu jmenu3=new JMenu("帮助");
    static JMenuItem jopen=new JMenuItem("打开");
    static JMenuItem jsave=new JMenuItem("保存");
    static JMenuItem jsaveas=new JMenuItem("另存为");
    private File file;

    Note()
    {
        jframe.setSize(700, 600);
        jframe.setVisible(true);
        WindowListener l=new WindowAdapter()
        {
            @Override
            public void windowClosing(WindowEvent e)
            {
                System.exit(0);
            }
        };
        jframe.addWindowListener(l);
        jframe.setJMenuBar(jmenubar);
        jmenu1.add(jopen);
        jmenu1.add(jsave);
        jmenu1.add(jsaveas);
        jmenubar.add(jmenu1);
        jmenubar.add(jmenu2);
        jmenubar.add(jmenu3);
        final JTextArea jtext=new JTextArea();
        JScrollPane jpane=new JScrollPane(jtext);
        jframe.add(jpane);
        ////////////////////////////////////////////////打开
        jopen.addActionListener(new ActionListener()
        {
            public void actionPerformed(ActionEvent e) {
                  JFileChooser fselect = new JFileChooser();
                  fselect.showOpenDialog(null);
                  file = fselect.getSelectedFile();

                  try {
                         FileReader fr = new FileReader(file);
                         BufferedReader br = new BufferedReader(fr);
                         String line = br.readLine();
                         String str = ""; //保存文件中的字符串
                         while (line != null) {
                         jtext.append(line + "\n");
                         line = br.readLine();
                      }
                      br.close();
                      fr.close();
                      } 
                      catch (Exception ex) {
                        System.out.println(ex);
                      }
            }
        }
        );
        ///////////////////////////////////////////////////////保存
        jsave.addActionListener(new ActionListener()
        {
        public void actionPerformed(ActionEvent e) {
        if (file == null) {
        //打开对话框
        JFileChooser fselect = new JFileChooser();
        fselect.showSaveDialog(null);
        //读取
        file = fselect.getSelectedFile();}
                           
        try {
                   FileWriter fw = null;
                    try {
                        fw = new FileWriter(file);
                    } catch (IOException ex) {
                        Logger.getLogger(Note.class.getName()).log(Level.SEVERE, null, ex);
                    }
                    BufferedWriter bw = new BufferedWriter(fw);
                    bw.write(jtext.getText());
                    bw.flush();
                    fw.close();
           }
        catch (IOException ex)
        {
        System.out.println(ex);
        }
        }}
        );
        }
    public static void main(String[] args) {
       Note n=new Note();
       //n.OpenClickPerformed(e);
       
        Note.jframe.setVisible(true);

        // TODO code application logic here
    }
}


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