GetImage.java顯示網路上的圖片

import java.net.*;
import java.io.*;
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;

public class GetImage extends JFrame{
    Container theContainer;
        JTextField theTextField;
        JButton theButton;
        Toolkit theToolkit;
        Image theImage;
        URL theURL;
    public GetImage() {
        super("從網路取得圖片");
        theContainer = super.getContentPane();
        theTextField = new JTextField(18);
        theContainer.add(theTextField);
        theButton = new JButton("輸入網址");
        theContainer.add(theButton);
        theToolkit = getToolkit();
        
        
        theButton.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent e) {
                try {
                    theURL = new URL(theTextField.getText());
                    theImage = theToolkit.getImage(theURL);
                    repaint();    
                }catch(MalformedURLException malformedEx) {
                    JOptionPane.showMessageDialog(null,"不合標準的URL格式!");
                }catch(IOException ioEx) {
                    JOptionPane.showMessageDialog(null,"發生IO例外!");
                }catch(Exception Ex) {
                    JOptionPane.showMessageDialog(null,"發生例外!");
                }
            }
        });
        
        
        
        
        
        pack();
        setLayout(new FlowLayout(FlowLayout.CENTER));
        setVisible(true);
        setBounds(100,100,400,300);
        
    }
    public void paint(Graphics g) {
            super.paint(g);
            if(theImage != null) {
                g.drawImage(theImage,20,80,this);
            }

    }

    public static void main(String[] args) {
        GetImage demo = new GetImage();
    }
}