当applet在Web浏览器上运行时，JFilechooser无法正常工作

Question

当applet在浏览器上运行时，JFileChooser无法正常工作。将出现GUI，但单击“浏览”按钮时不会执行任何操作，并显示空白文件系统。当从Eclipse测试applet时，在网页之外JFileChooser工作正常。如何让JFileChooser访问本地文件？

import java.awt.Color;
import java.awt.Font;
import java.awt.Graphics2D;
import java.awt.Image;
import java.awt.RenderingHints;
import java.awt.SystemColor;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;
import java.nio.file.Path;
import java.util.Scanner;
import javax.imageio.ImageIO;
import javax.print.DocFlavor.BYTE_ARRAY;
import javax.swing.ImageIcon;
import javax.swing.JButton;
import javax.swing.JFileChooser;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JTextField;

public class Test extends javax.swing.JApplet{
JFrame frame = new JFrame();// frame
JTextField textField_path = new JTextField();// browse path
JButton btnBrowse = new JButton("Browse");
JLabel Jlabel_image1 = new JLabel(" ");
JLabel Jlabel_image2 = new JLabel(" ");
JButton btnSave = new JButton("Save");

BufferedImage img = null;
BufferedImage image1 =null;
BufferedImage capture = null;

// function to rescale the image to fit in the frame
private Image ScaledImage(BufferedImage image, int w,int h){
    BufferedImage resizeimage = new             BufferedImage(w,h,BufferedImage.TYPE_INT_BGR);
    Graphics2D g2= resizeimage.createGraphics();
    g2.setRenderingHint(RenderingHints.KEY_INTERPOLATION, RenderingHints.VALUE_INTERPOLATION_BILINEAR);
    g2.drawImage(image,0,0,w,h,null);
    g2.dispose();
    return resizeimage; 
}


public Test() {

    // set the framesize
    frame.getContentPane().setBackground(new Color(169, 169, 169));
    frame.setSize(900,700);//2
    frame.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);//3
    frame.setLocationRelativeTo(null);
    textField_path.setForeground(new Color(0, 0, 0));
    textField_path.setBackground(new Color(245, 245, 220));

    //set the text path for browsing
    textField_path.setBounds(114, 626, 507, 23);
    frame.getContentPane().setLayout(null);//intially set the path field empty
    frame.getContentPane().add(textField_path);
    Jlabel_image1.setBackground(SystemColor.inactiveCaptionBorder);


    //set the label for original image
    Jlabel_image1.setBounds(142, 29, 429, 267);
    frame.getContentPane().add(Jlabel_image1);

    //set the label for gray image
    Jlabel_image2.setBounds(142, 345, 429, 267);
    frame.getContentPane().add(Jlabel_image2);
    btnBrowse.setFont(new Font("Cambria Math", Font.PLAIN, 13));

    //set the BROWSE button
    btnBrowse.setBounds(714, 621, 89, 30);
    frame.getContentPane().add(btnBrowse);
    btnSave.setFont(new Font("Cambria Math", Font.PLAIN, 13));


    //set the save button
    btnSave.setBounds(714, 580, 89, 30);
    frame.getContentPane().add(btnSave);


    // actionlistener for save button

    btnSave.addActionListener(new ActionListener() {
        public void actionPerformed(ActionEvent e) {
            JFileChooser jFile = new JFileChooser();
            jFile.showSaveDialog(null);
            Path pth = jFile.getSelectedFile().toPath();
            //JOptionPane.showMessageDialog(null, pth.toString());
            //Graphics2D graphics2D = image1.createGraphics();
            try { 
                ImageIO.write(img, "png", new File(pth.toString()));
            } catch (IOException ox) {
                // TODO: handle exception
                ox.printStackTrace();

            }
        }
    });

    // actonlistener for browse button

    btnBrowse.addActionListener(new ActionListener() {
        public void actionPerformed(ActionEvent e) {
            System.out.println("browse button");
             JFileChooser chooser = new JFileChooser();
             int figure = chooser.showOpenDialog(chooser);
                if (figure == JFileChooser.APPROVE_OPTION) {
                    File file = chooser.getSelectedFile();               
                    if(!file.exists()){
                        return;
                    }
                    try {
                         String filedetails[]= new String[2];
                            filedetails[0]=file.getName();
                            filedetails[1]=file.getAbsolutePath(); 
                            textField_path.setText(filedetails[1]);// display the path of the image browsed                             
                            img=ImageIO.read(file);
                            image1 =ImageIO.read(file);                 
                            for (int i = 0; i < image1.getWidth(); i++) {           
                                for (int j = 0; j < image1.getHeight(); j++) {              
                                    Color color = new Color(image1.getRGB(i,j));
                                    int red = color.getRed();
                                    int green = color.getGreen();
                                    int blue = color.getBlue();
                                    int gray = (int)(red * 0.299 + green * 0.587 + blue * 0.114);
                                    color = new Color(gray, gray, gray);
                                    int rgb = color.getRGB();
                                    image1.setRGB(i, j, rgb);
                                }                
                            }
                            //*********** display image on jframe*********
                            ImageIcon grayimage  = new ImageIcon(ScaledImage(image1, Jlabel_image1.getWidth(), Jlabel_image1.getHeight()));   
                            Jlabel_image1.setIcon(grayimage);         
                            frame.getContentPane().add(Jlabel_image1);
                            ImageIcon originalimage  = new ImageIcon(ScaledImage(img, Jlabel_image2.getWidth(), Jlabel_image2.getHeight()));    
                            Jlabel_image2.setIcon(originalimage);         
                            frame.getContentPane().add(Jlabel_image2);

                            } catch (IOException e1) {
                                // TODO Auto-generated catch block
                                e1.printStackTrace();
                            }
                        }
                    }
                });


                frame.setVisible(true);

            }
public static void main(String[] args) {
Test jb = new Test();
}
}