界面编程 文件IO 监听

package MyNote;

import java.awt.BorderLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.io.*;

import javax.swing.*;

public class MyNote extends JFrame implements ActionListener{

/**
* @param args
*/
JTextArea jta;
JScrollPane jsp;

JMenuBar jmb;
JMenu jm;
JMenuItem jmi1,jmi2;
public static void main(String[] args) {
// TODO Auto-generated method stub
MyNote mn = new MyNote();
}

public MyNote(){
jta = new JTextArea();
jsp = new JScrollPane(jta);
jmb = new JMenuBar();
jm = new JMenu("File");
jmi1 = new JMenuItem("open");
jmi2 = new JMenuItem("save");
jmi1.addActionListener(this);
jmi1.setActionCommand("open");
jmi2.addActionListener(this);
jmi2.setActionCommand("save");

this.setJMenuBar(jmb);
jm.add(jmi1);
jm.add(jmi2);
jmb.add(jm);

this.add(jsp);
this.setSize(400,300);
this.setVisible(true);
this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
}

@Override
public void actionPerformed(ActionEvent e) {
// TODO Auto-generated method stub
if(e.getActionCommand().equals("open")){
System.out.println("open");
JFileChooser fc = new JFileChooser("dd");
fc.setDialogTitle("请选择");
fc.showOpenDialog(null);
fc.setVisible(true);

String s = fc.getSelectedFile().getAbsolutePath();
System.out.print(s);

FileReader fr =null;
BufferedReader br=null;
String str = "";
String str1 = "";

try {
fr = new FileReader(s);
br = new BufferedReader(fr);

int n=0;
while((str=br.readLine())!=null){
str1 = str1+str+"\r\n";
}
} catch (Exception e1) {
// TODO Auto-generated catch block
e1.printStackTrace();
}finally{
try {
br.close();
} catch (IOException e1) {
// TODO Auto-generated catch block
e1.printStackTrace();
}
}

jta.setText(str1);

}
}
}