Exec69 多线程

import javax.swing.*;
import java.awt.event.*;
import java.awt.*;
public class Exec69 extends JFrame{
    JTextField text;
    JTextArea re;
    JLabel label;
    public Exec69() {
        setSize(400,400);
        setTitle("Exec69");
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        setLocationRelativeTo(null);
        
        text = new JTextField(20);
        text.addKeyListener(new KeyLis());
        re = new JTextArea(5,10);
        add(text,BorderLayout.NORTH);
        
        label = new JLabel("            ");
        add(label,BorderLayout.SOUTH);
        JScrollPane js = new JScrollPane(re);
        js.setHorizontalScrollBarPolicy(ScrollPaneConstants.HORIZONTAL_SCROLLBAR_NEVER);
        add(js);
        setVisible(true);
        pack();
    }

    /**
     * @param args
     */
    public static void main(String[] args) {
        new Exec69();
    }
    private long getSum(long s) {
        long ret = 0;
        for(long i=1;i<=s;i++) ret+=i;
        return ret;
        
    }
    class KeyLis extends KeyAdapter {
        StringBuilder str = new StringBuilder();
        public void keyPressed(KeyEvent e) {
            if ((e.getKeyCode()>=KeyEvent.VK_0)&&(e.getKeyCode()<=KeyEvent.VK_9)) {
                //System.out.println(e.getKeyChar());
                str.append(e.getKeyChar());
            }
            else if(e.getKeyCode()==KeyEvent.VK_ENTER) {
                String s = str.toString();
                if (s.equals("")) s="0";
                final long num = Long.valueOf(s);
                new Thread(new Runnable(){
                    public void run(){
                        re.setText(String.valueOf(getSum(Long.valueOf(num))));
                        label.setText("1-"+num+"的和");
                    }
                }).start();
                //label.setText(String.valueOf(getSum(Long.valueOf(num))));
                str = new StringBuilder();
                text.setText("");
            }
            else {
                text.setText("");
                text.setText("输入错误!!");
                
                str = new StringBuilder();
            }
        }
    }
}