How to show uploaded and saved photo from database to a JLabel

Question

I am making a system where the user can save a picture and database. It is already saving, but I want that saved photo to be displayed on a JLabel when I click it from the JTable. I don't know the code on how make it appear, and I want it to be automatically resized according to the size of my JLabel.

Here is the code for the Table Mouse Clicked Event:

private void tblTableMouseClicked(java.awt.event.MouseEvent evt) {                                      
        int row = tblTable.getSelectedRow();
        String selection = tblTable.getModel().getValueAt(row, 0).toString();
        String sql = "select * from LibrarySystemDatabase where No = " + selection;
        try {
            pst = conn.prepareStatement(sql);
            rs = pst.executeQuery();
            if (rs.next()) {
                txtNo.setText(rs.getString("No"));
                txtTitle.setText(rs.getString("Title"));
                txtAuthor.setText(rs.getString("Author"));
                txtGenre.setText(rs.getString("Genre"));
                txtLexile.setText(rs.getString("Lexile"));
                txtPoints.setText(rs.getString("Points"));


            }
        } catch (Exception e) {
            JOptionPane.showMessageDialog(null, e);
        } finally {
            try {
                rs.close();
                pst.close();
            } catch (Exception e) {
            }
        }
    }

Here is the code for the Upload Button:

private void btnUploadActionPerformed(java.awt.event.ActionEvent evt) {                                          


        JFileChooser chooser = new JFileChooser();
        chooser.showOpenDialog(null);
        File f = chooser.getSelectedFile();
        filename = f.getAbsolutePath();

        ImageIcon imageIcon =  new ImageIcon (new ImageIcon(filename).getImage().getScaledInstance(lblImage.getWidth(), lblImage.getHeight(), Image.SCALE_DEFAULT));
        lblImage.setIcon(imageIcon);



        try {


            File image = new File(filename);
            FileInputStream fix = new FileInputStream(image);
            ByteArrayOutputStream bos = new ByteArrayOutputStream();
            byte[] buf = new byte[1024];
            for (int number; (number = fix.read(buf)) != -1;) {
                bos.write(buf, 0, number);
            }
            bookImage = bos.toByteArray();
        } catch (Exception e) {
            JOptionPane.showMessageDialog(null, e);
        }
//*/
    }

    byte[] bookImage = null;
    String filename = null;
    private ImageIcon format = null;

Thanks!

Is this question just about displaying an image on a JLabel at different sizes? It seems like you have a lot of extra information. — matt, Feb 26 '20 at 08:27
I want the image to be automatically resized and displayed according to JLabel size — zultz, Feb 26 '20 at 08:34
So this doesn't have anything to do with a database? What about solutions found here? https://stackoverflow.com/questions/16343098/resize-a-picture-to-fit-a-jlabel — matt, Feb 26 '20 at 08:36
The images are save into database,what i want to happen to retrieve the image from database and show it into a JLabel — zultz, Feb 26 '20 at 08:54
Right now you can retrieve and show the images? The only issue you're having is the scaling of the JLabel? Ie if I have an example of a jlabel that scales the displayed image to display as much as possible then you could put the reset together? — matt, Feb 26 '20 at 08:55
Quit reposting questions. This is your 3rd question on this topic. Your question is NOT clear and you were asked in your last question: https://stackoverflow.com/q/60403831/131872 to post a [mre]. You haven't. Your question is about showing an image in a label. So all you need to demonstrate the problem is a JFrame with a JLabel (with a preferred size) and a JButton. When you click the button you read the image and scale it to the size of the label. The entire code will 20-30 lines. Then once you understand the basic concept of scaling an image to fit your label you fix your real code. — camickr, Feb 26 '20 at 15:24
Also, you question looks similar to this question: https://stackoverflow.com/questions/60406636/how-to-put-getscaledinstance (a friend of yours?). That posting contains a solution where you don't even need to create a scaled instance of the image. It will dynamically resize. — camickr, Feb 26 '20 at 15:29

score 0 · Answer 1 · answered Feb 26 '20 at 09:10

As it isn't clear when you'll know the size of your JLabel, I created a listener that can resize the JLabels icon when necessary.

static public JLabel getScalingJLabel(BufferedImage img){
    JLabel z1 = new JLabel( new ImageIcon(img) );
    z1.addComponentListener( new ComponentAdapter(){
        @Override
        public void componentResized(ComponentEvent e){
            JLabel label = (JLabel)e.getComponent();

            int w = img.getWidth();
            int h = img.getHeight();
            int cw = label.getWidth();
            int ch = label.getHeight();

            //constrains the sizes.
            int mw = cw>w ? w : cw;
            int mh = ch>h ? h : ch;

            //for iso-tropic scaling.
            if( mw != w || mh != h ){
                int scaled_height = h*mw/w;
                int scaled_width = w*mh/h;

                if (scaled_height>mh){
                    mw = scaled_width;
                } else{
                    mh = scaled_height;
                }
            }

            Icon i = label.getIcon();

            if( i.getIconWidth() == mw && i.getIconHeight() == mh ){
                //no change.
            } else{
                label.setIcon( new ImageIcon( img.getScaledInstance( mw, mh, Image.SCALE_FAST ) ) );
            }
        }
    } );
    return z1;
}

It looks like what you're doing, but I scale the icon when the label gets resized so you don't have to know the final dimensions, but swing will take care of it.

How to show uploaded and saved photo from database to a JLabel

1 Answers1