第六次JAVA作业

import java.awt.GridLayout;
import java.awt.event.MouseEvent;
import java.awt.event.MouseListener;
import java.util.Iterator;
import java.util.Random;
import java.util.Set;
import java.util.TreeSet;

import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JTextField;

public class cj {

private JFrame f = new JFrame("Lucky Drawn");
private JButton btn = new JButton("Drawn");
private JTextField result = new JTextField("Result");
private static final int MIN = 1;
private static final int MAX = 30;
private static final int RESULT_COUNT = 7;

public cj(){
f.add(btn);
f.add(result);
result.setEditable(false);

btn.addMouseListener(new MouseListener(){

public void mouseClicked(MouseEvent e) {

Random rand = new Random();

Set<Integer> set = new TreeSet<Integer>();

while(set.size() < RESULT_COUNT){
set.add(new Integer(rand.nextInt(MAX)+ 1));
}

StringBuffer sb = new StringBuffer("Lucky numbers are: ");
for (Iterator iter = set.iterator(); iter.hasNext();) {
sb.append(((Integer) iter.next()).intValue()).append(", ");
}

result.setText(sb.substring(0, sb.length() - 2).toString());
f.pack();
}

public void mouseEntered(MouseEvent e) {}
public void mouseExited(MouseEvent e) {}
public void mousePressed(MouseEvent e) {}
public void mouseReleased(MouseEvent e) {}
});

f.setLayout(new GridLayout(2, 1));
f.setVisible(true);
f.setLocation(500, 200);
f.pack();
f.validate();
f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
}

public static void main(String[] args) {
new cj();
}

}