成角透视书本:java编程问题

import java.awt.*;import java.awt.event.*;
import javax.swing.JOptionPane;
class Dwindow extends Frame implements ActionListener
{
TextField inputnumber;
TextArea show;
Dwindow(String s)
{
super(s);
inputnumber=new TextField(22);show=new TextArea();
inputnumber.addActionListener(this);
add(inputnumber,BorderLayout.NORTH);add(show,BorderLayout.CENTER);
setBounds(60,60,300,300);setVisible(true);
validate();
addWindowListener(new WindowAdapter()
{
public void windowClosing(WindowEvent e)
{
System.exit(0);
}
});
}
public void actionPerformed(ActionEvent e)
{
boolean boo=false;
if(e.getSource()==inputnumber)
{
String s=inputnumber.getText();
char a[]=s.toCharArray();
for(int i=0;i<a.length;i++)
{
if(!(Character.isDigit(a[i])))
boo=true;
}
if(boo==true)
{
JOptionPane.showMessageDialog(this,"你输入了非法字符",
"警告对话框",JOptionPane.WARNING_MESSAGE);
inputnumber.setText(null);
}
else if(boo==false)
{
int number=Integer.parseInt(s);
show.append("\n"+number+"平方:"+(number.number));
}
}
}
}
public class ex4
{
public static void main(String args[])
{
new Dwindow("带对话框的窗口");
}
}

错在什么地方，帮我改下，正确了后追加分数，谢了~~~~