javaSE学习笔记——随机点名器

近来上课想做一个随机点名的小软件，刚刚写了一个，望大家指正。

import java.io.*;import java.awt.*;import java.awt.event.*;import java.util.List;import java.util.ArrayList;public class DianName extends Frame{private String fileName="a.txt";private File f;private FileReader fr;private BufferedReader br;private List<String> names=new ArrayList<String>();private String strName;private Label labelName;private Button btOK;public static void main(String[] args){DianName dn=new DianName();dn.newFrame();dn.read();}public void newFrame(){labelName=new Label("显示姓名");btOK=new Button("开始");this.setLocation(300,300);this.setResizable(false);this.setSize(500,400);this.add(labelName,BorderLayout.NORTH);this.add(btOK,BorderLayout.SOUTH);this.pack();this.setVisible(true);this.addWindowListener(new WindowAdapter(){public void windowClosing(WindowEvent e){System.exit(0);}});btOK.addActionListener(new ButtonAction());}public void read(){try{f=new File(fileName);if(!f.exists()){f.createNewFile();}fr=new FileReader(f);br=new BufferedReader(fr);String str=br.readLine();while(str!=null){names.add(str);str=br.readLine();}}catch(Exception e){e.printStackTrace();}}public void write(){try{int index=(int)(Math.random()*names.size());strName=names.get(index);}catch(Exception e){e.printStackTrace();}}private class ButtonAction implements ActionListener{public void actionPerformed(ActionEvent e){write();labelName.setText(strName);}}}