关于在APPLICATION中显示JPEG图象问题??

Question

一个类似的基本图形处理程序：
import java.awt.*;
import java.awt.event.*;
import java.awt.geom.*;
import java.awt.image.*;
import java.io.*;
import javax.imageio.*;
import javax.swing.*;public class ImageProcessingTest
{ 
   public static void main(String[] args)
   {  
      JFrame frame = new ImageProcessingFrame();
      frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
      frame.show();
   }
}/**
   This frame has a menu to load an image and to specify
   various transformations, and a panel to show the resulting
   image.
*/
class ImageProcessingFrame extends JFrame
{  
   public ImageProcessingFrame()
   {  
      setTitle("ImageProcessingTest");
      setSize(WIDTH, HEIGHT);      JPanel panel = new 
         JPanel()
         {  
            public void paintComponent(Graphics g)
            {  
               super.paintComponent(g);
               if (image != null)
                  g.drawImage(image, 0, 0, null);
            }
         };      getContentPane().add(panel, BorderLayout.CENTER);      JMenu fileMenu = new JMenu("File");
      JMenuItem openItem = new JMenuItem("Open");
      openItem.addActionListener(new
         ActionListener()
         {
            public void actionPerformed(ActionEvent event)
            {
               openFile();
            }
         });
      fileMenu.add(openItem);      JMenuItem exitItem = new JMenuItem("Exit");
      exitItem.addActionListener(new
         ActionListener()
         {
            public void actionPerformed(ActionEvent event)
            {
               System.exit(0);
            }
         });
      fileMenu.add(exitItem);      JMenu editMenu = new JMenu("Edit");
      JMenuItem blurItem = new JMenuItem("Blur");
      blurItem.addActionListener(new
         ActionListener()
         {
            public void actionPerformed(ActionEvent event)
            {
               float weight = 1.0f/9.0f;
               float[] elements = new float[9];
               for (int i = 0; i < 9; i++)
                  elements[i] = weight;
               convolve(elements);
            }
         });
      editMenu.add(blurItem);            JMenuItem brightenItem = new JMenuItem("Brighten");
      brightenItem.addActionListener(new
         ActionListener()
         {
            public void actionPerformed(ActionEvent event)
            {
               float a = 1.5f;
               float b = -20.0f;
               RescaleOp op = new RescaleOp(a, b, null);
               filter(op);
            }
         });
      editMenu.add(brightenItem);      JMenuItem edgeDetectItem = new JMenuItem("Edge detect");
      edgeDetectItem.addActionListener(new
         ActionListener()
         {
            public void actionPerformed(ActionEvent event)
            {
               float[] elements =
               {  0.0f, -1.0f, 0.0f,
                  -1.0f,  4.f, -1.0f,
                  0.0f, -1.0f, 0.0f
               };
               convolve(elements);
            }
         });
      editMenu.add(edgeDetectItem);      JMenuItem negativeItem = new JMenuItem("Negative");
      negativeItem.addActionListener(new
         ActionListener()
         {
            public void actionPerformed(ActionEvent event)
            {
               byte negative[] = new byte[256];
               for (int i = 0; i < 256; i++)
                  negative[i] = (byte)(255 - i);
               ByteLookupTable table 
                  = new ByteLookupTable(0, negative);
               LookupOp op = new LookupOp(table, null);
               filter(op);
            }
         });
      editMenu.add(negativeItem);      JMenuItem rotateItem = new JMenuItem("Rotate");
      rotateItem.addActionListener(new
         ActionListener()
         {
            public void actionPerformed(ActionEvent event)
            {
               AffineTransform transform
                  = AffineTransform.getRotateInstance(
                     Math.toRadians(5),
                     image.getWidth() / 2, 
                     image.getHeight() / 2);
               AffineTransformOp op 
                  = new AffineTransformOp(transform,
                     AffineTransformOp.TYPE_BILINEAR);
               filter(op);
            }
         });
      editMenu.add(rotateItem);      JMenuBar menuBar = new JMenuBar();
      menuBar.add(fileMenu);
      menuBar.add(editMenu);
      setJMenuBar(menuBar);
   }   /**
      Open a file and load the image.
   */
   public void openFile()
   {  
      JFileChooser chooser = new JFileChooser();
      chooser.setCurrentDirectory(new File("."));
      
      chooser.setFileFilter(new
         javax.swing.filechooser.FileFilter()
         {  
            public boolean accept(File f)
            {  
               String name = f.getName().toLowerCase();
               return name.endsWith(".gif")
                  || name.endsWith(".jpg")
                  || name.endsWith(".jpeg")
                  || name.endsWith(".bmp")
                  || f.isDirectory();
            }
            public String getDescription()
            {  
               return "Image files";
            }
         });      int r = chooser.showOpenDialog(this);
      if(r != JFileChooser.APPROVE_OPTION) return;      try
      {
         image = ImageIO.read(chooser.getSelectedFile());
      }
      catch (IOException exception)
      {
         JOptionPane.showMessageDialog(this, exception);
      }
      repaint();
   }   /**
      Apply a filter and repaint.
      @param op the image operation to apply
   */
   private void filter(BufferedImageOp op)
   {  
      BufferedImage filteredImage
         = new BufferedImage(image.getWidth(), image.getHeight(),
            image.getType());
      op.filter(image, filteredImage);
      image = filteredImage;
      repaint();
   }   /**
      Apply a convolution and repaint.
      @param elements the convolution kernel (an array of
      9 matrix elements)
   */
   private void convolve(float[] elements)
   {  
      Kernel kernel = new Kernel(3, 3, elements);
      ConvolveOp op = new ConvolveOp(kernel);
      filter(op);
   }   private BufferedImage image;
   private static final int WIDTH = 400;
   private static final int HEIGHT = 400;
}