java 随机抽奖程序

//设计一个图形化界面的随机抽奖程序,用户单击开始进行滚动抽奖，单击停止即可产生1~36之间的7个随机整数
import java.awt.Cursor;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;

import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JTextField;
public class GodLucky extends JFrame implements ActionListener {
	JTextField tf;
	JButton b1;
	JButton b2;
	boolean isGo;
	public GodLucky(){
		 tf = new JTextField();
		 b1 = new JButton("start");
		 b2 = new JButton("end");
		 b2.setEnabled(false);
		 isGo = false;
		 b1.setActionCommand("start");
		 b2.setActionCommand("end");
		 JPanel p1 = new JPanel();
		 p1.add(b1);
		 p1.add(b2);
		 b1.addActionListener(this);
		 b2.addActionListener(this);
		 this.getContentPane().add(tf,"North");
		 this.getContentPane().add(p1,"South");
		 
		 this.setTitle("随机抽奖程序");
		 this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
		 this.setSize(300,200);
		 this.setLocation(300, 300);
		 
		 Cursor cu = new Cursor(Cursor.HAND_CURSOR);
		 this.setCursor(cu);
		 
		 this.setVisible(true);
		 tf.setText("--------------welcome you!------------------");
		 this.go();
	}
	public static void main(String[] args) {
		new GodLucky();
	}
	public void actionPerformed(ActionEvent e){
		String s =e.getActionCommand();
		if(s.equals("start")){
			isGo =true;
			b1.setEnabled(false);
			b2.setEnabled(true);
		}
		else if(s.equals("end")){
			isGo =false;
			b1.setEnabled(true);
			b2.setEnabled(false);
		}
	}
	public void go(){
		while(true){
			if(isGo){
				String s = "";
				for(int j = 1;j <= 7; j++){
					int i=(int)(Math.random()*36)+1;
					if(i < 10){
						s = s+" 0"+i;
					}else{
						s=s+" "+i;
					}
				}
				tf.setText(s);
			}
			try{
				Thread.sleep(100);
			}catch(Exception e){
				e.printStackTrace();
			}
		}
		
	}
	
}