写了个程序，可是不是我想要的。。

import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
import java.util.Random;

public class GuessNumber extends JFrame {
    private JTextField tfNumber;
    private JButton btnGenerate;
    private JButton btnGuess;
    private JLabel lbTip;
    private int number;
    private Timer timer;
    private int usedTime;
   
    private Action generate = new AbstractAction("生成一个随机数") {
        public void actionPerformed(ActionEvent e) {
            number = new Random().nextInt(1000); // 0 ~ 999之间的随机数
            lbTip.setText("请猜一猜这个数是多少？");
            generate.setEnabled(false);
            guess.setEnabled(true);
            timer.start();
        }
    };
   
    private Action guess = new AbstractAction("猜一猜") {
        public void actionPerformed(ActionEvent e) {
            String textNumber = tfNumber.getText().trim();
            if (textNumber.isEmpty())
                lbTip.setText("您还没有输入数字！");
            else {
                try {
                    int guessNumber = Integer.parseInt(textNumber);
                    if (guessNumber == number) {
                        lbTip.setText("恭喜您猜中啦！用时：" + (usedTime / 100.0) + "秒！");
                        timer.stop();
                        usedTime = 0;
                        generate.setEnabled(true);
                        guess.setEnabled(false);
                    } else if (guessNumber > number) {
                        lbTip.setText("您猜的数字有点大！");
                    } else {
                        lbTip.setText("您猜的数字有点小！");
                    }
                } catch (NumberFormatException ex) {
                    lbTip.setText("请输入数字！");
                }
            }
        }
    };
   
    private ActionListener timerListener = new ActionListener() {
        public void actionPerformed(ActionEvent e) {
            usedTime += 1; // "增加0.01秒"
        }
    };
   
    public GuessNumber() {
        tfNumber = new JTextField(20);
        btnGenerate = new JButton(generate);
        btnGuess = new JButton(guess);
        lbTip = new JLabel("");
        guess.setEnabled(false);
      
        timer = new Timer(10, timerListener);
      
        JPanel topPanel = new JPanel(new FlowLayout(FlowLayout.LEFT));
        JPanel bottomPanel = new JPanel(new FlowLayout(FlowLayout.LEFT));
        topPanel.add(btnGenerate);
        topPanel.add(lbTip);
        bottomPanel.add(tfNumber);
        bottomPanel.add(btnGuess);
        add(topPanel, BorderLayout.NORTH);
        add(bottomPanel, BorderLayout.CENTER);
      
        setTitle("猜数字游戏");
        setDefaultCloseOperation(EXIT_ON_CLOSE);
        setSize(400, 200);
        setLocation(300, 300);
    }
   
    public static void main(String[] args) throws Exception {
        UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
        SwingUtilities.invokeLater(new Runnable() {
            public void run() {
                new GuessNumber().setVisible(true);
            }
        });
    }
}