Java做的一个小程序,随机点名器

Java做的一个小程序，随机点名器
1.import java.io.*;
2.import java.awt.*;
3.import java.awt.event.*;
4.import java.util.List;
5.import java.util.ArrayList;
6.
7.public class DianName extends Frame{
8.
9.private String fileName="a.txt";
10.private File f;
11.private FileReader fr;
12.private BufferedReader br;
13.private List<String> names=new ArrayList<String>();
14.private String strName;
15.
16.private Label labelName;
17.private Button btOK;
18.
19.public static void main(String[] args){
20. DianName dn=new DianName();
21. dn.newFrame();
22. dn.read();
23. }
24.
25.public void newFrame(){
26. labelName=new Label("显示姓名");
27. btOK=new Button("开始");
28.
29.this.setLocation(300,300);
30.this.setResizable(false);
31.this.setSize(500,400);
32.this.add(labelName,BorderLayout.NORTH);
33.this.add(btOK,BorderLayout.SOUTH);
34.this.pack();
35.this.setVisible(true);
36.this.addWindowListener(new WindowAdapter(){
37.public void windowClosing(WindowEvent e){
38. System.exit(0);
39. }
40. });
41. btOK.addActionListener(new ButtonAction());
42. }
43.
44.public void read(){
45.try{
46. f=new File(fileName);
47.if(!f.exists()){
48. f.createNewFile();
49. }
50. fr=new FileReader(f);
51. br=new BufferedReader(fr);
52. String str=br.readLine();
53.while(str!=null){
54. names.add(str);
55. str=br.readLine();
56. }
57. }catch(Exception e){
58. e.printStackTrace();
59. }
60.
61. }
62.
63.public void write(){
64.try{
65.int index=(int)(Math.random()*names.size());
66. strName=names.get(index);
67. }catch(Exception e){
68. e.printStackTrace();
69. }
70.
71. }
72.
73.private class ButtonAction implements ActionListener{
74.public void actionPerformed(ActionEvent e){
75. write();
76. labelName.setText(strName);
77. }
78. }
79.}。