Using Eclipse SWT Image, JAVA and SQLite to insert, store and retrieve Images

Question

I'm writing a basic Java application that allows a user to insert details about individuals into an SQLite database. I'm using Eclipse SWT for the GUI.

Eclipse SWT defines a type Image (org.eclipse.swt.graphics.Image) for displaying Images in a GUI.

I am trying to allow a user to browse the file system, select an image and then insert that image into a database. I also want to be able to retrieve that image from the database and display it in the GUI.

All pretty straightforward, but for the life of me I can't get it to work! I've searched around a lot too and can't seem to find a solution to this.

I'm using Eclipse IDE for Java Developers (3.6), sqlite-jdbc-3.7.2.jar and JDK 1.6.0_22.

import org.eclipse.swt.*;
import org.eclipse.swt.events.*;
import org.eclipse.swt.layout.*;
import org.eclipse.swt.widgets.*;
import org.eclipse.swt.graphics.*;

import java.sql.*;

/***********************************************************************/
/*** Tests reading and writing SWT Images from an SQLite Database    ***/
/***********************************************************************/
public class ImageTest {

    Shell shell;

    //Variables to store the current values when editing
    private Canvas personPhoto;
    private Image personImage;
    private int personID = 1;

    private double photoWidth = 100;
    private double photoHeight = 100;

    //Database connection and statement variables
    private static Connection connection = null;
    private static Statement statement = null;
    private static PreparedStatement ps = null;
    private static ResultSet rs = null;

    public ImageTest(Shell parent, Connection passedConnection) {
        shell = new Shell(parent, SWT.DIALOG_TRIM | SWT.PRIMARY_MODAL);
        shell.setLayout(new GridLayout());
        connection = passedConnection;
    }

    private void createControlButtons() {
        Composite composite = new Composite(shell, SWT.NONE);
        composite.setLayoutData(new GridData(GridData.HORIZONTAL_ALIGN_END));
        GridLayout layout = new GridLayout();
        layout.numColumns = 2;
        composite.setLayout(layout);

        Button okButton = new Button(composite, SWT.PUSH);
        okButton.setText("OK");
        okButton.addSelectionListener(new SelectionAdapter() {
            public void widgetSelected(SelectionEvent e) {
                if(personID > 0){
                    try {
                        PreparedStatement ps = connection.prepareStatement("UPDATE person SET photo = ? " +
                                                                                              "WHERE person_id = ?");
                        ps.setBytes(1, personImage.getImageData().data);
                        ps.setInt(2, personID);
                        ps.executeUpdate();
                        ps.close();
                    } catch (SQLException err) {
                        err.printStackTrace();
                    }
                } else {
                    try {
                        PreparedStatement ps = connection.prepareStatement("INSERT INTO person (photo) VALUES (?)");
                        ps.setBytes(1, personImage.getImageData().data);
                        ps.executeUpdate();
                        ps.close();
                    } catch (SQLException err) {
                        err.printStackTrace();
                    }
                }               
                shell.close();
            }
        });

        Button cancelButton = new Button(composite, SWT.PUSH);
        cancelButton.setText("Cancel");
        cancelButton.addSelectionListener(new SelectionAdapter() {
            public void widgetSelected(SelectionEvent e) {
                shell.close();
            }
        });

        shell.setDefaultButton(okButton);
    }

    private void createTextWidgets(final Display display) {

        GridLayout gridLayout = new GridLayout();
        gridLayout.numColumns = 2;
        shell.setLayout(gridLayout);
        new Label(shell, SWT.NONE).setText("Photo:");

        personPhoto = new Canvas(shell, SWT.BORDER);
        GridData gridData = new GridData(GridData.FILL, GridData.FILL, true, true);
        gridData.widthHint = (int)photoWidth;
        gridData.heightHint = (int)photoHeight;
        gridData.verticalSpan = 5;
        gridData.horizontalSpan = 2;
        personPhoto.setLayoutData(gridData);
        personPhoto.redraw();

        personPhoto.addPaintListener(new PaintListener() {
            public void paintControl(final PaintEvent event) {
                if (personImage != null) {
                    event.gc.drawImage(personImage, 0, 0);
                }
            }
        });

        //Skip a Column
        new Label(shell, SWT.NONE);

        Button browse = new Button(shell, SWT.PUSH);
        browse.setText("Browse...");
        gridData = new GridData(GridData.FILL, GridData.CENTER, true, false);
        gridData.horizontalIndent = 5;
        browse.setLayoutData(gridData);
        browse.addSelectionListener(new SelectionAdapter() {
            public void widgetSelected(SelectionEvent event) {
                String fileName = new FileDialog(shell).open();
                if (fileName != null) {
                    personImage = new Image(display, fileName);
                    personPhoto.redraw();
                }
            }
        });

        Button delete = new Button(shell, SWT.PUSH);
        delete.setText("Delete");
        gridData = new GridData(GridData.FILL, GridData.BEGINNING, true, false);
        gridData.horizontalIndent = 5;
        delete.setLayoutData(gridData);
        delete.addSelectionListener(new SelectionAdapter() {
            public void widgetSelected(SelectionEvent event) {
                if (personImage != null) {
                    personImage.dispose();
                    personImage = null;
                    personPhoto.redraw();
                }
            }
        });

        //Skip a Column
        new Label(shell, SWT.NONE);

        //Skip two Rows
        new Label(shell, SWT.NONE);
        new Label(shell, SWT.NONE);
        new Label(shell, SWT.NONE);
        new Label(shell, SWT.NONE);     
    }

    public void open() {
        Display display = shell.getDisplay();
        //To avoid null pointer exceptions
        personImage = new Image(display,"user.png");

        try{
            PreparedStatement ps = connection.prepareStatement("SELECT photo FROM person WHERE person_id = ?");
            ps.setInt(1, personID);
            rs = ps.executeQuery();
            while (rs.next()) {
                //dispose of the current image
                personImage.dispose();
                personImage = new Image(display, (int) photoWidth, (int) photoHeight);
                //Retrieve the photo for this person
                personImage.getImageData().data = rs.getBytes("photo");
            }
            ps.close();
            rs.close();    
        } catch (SQLException e) {
            e.printStackTrace();
        }

        createTextWidgets(display);
        createControlButtons();
        shell.pack();
        shell.open();
        while(!shell.isDisposed()){
            if(!display.readAndDispatch())
                display.sleep();
        }
    }
}

---

I have simplified the code down now, but I still can't get it to correctly pull the byte array from the database and display it as an SWT Image. Anybody have any ideas? Any help would be really appreciated!

Shay

    /* Imports */
import org.eclipse.swt.*;
import org.eclipse.swt.events.*;
import org.eclipse.swt.layout.*;
import org.eclipse.swt.widgets.*;
import org.eclipse.swt.graphics.*;

import java.sql.*;

/***********************************************************************/
/*** Tests reading and writing SWT Images from an SQLite Database    ***/
/***********************************************************************/
public class ImageTest {

    Shell shell;

    //Variables to store the current values when editing
    private Canvas personPhoto;
    private Image personImage;
    private int personID = 1;

    private double photoWidth = 100;
    private double photoHeight = 100;

    //Database connection and statement variables
    private static Connection connection = null;
    private static Statement statement = null;
    private static PreparedStatement ps = null;
    private static ResultSet rs = null;

    public ImageTest(Shell parent, Connection passedConnection) {
        shell = new Shell(parent, SWT.DIALOG_TRIM | SWT.PRIMARY_MODAL);
        shell.setLayout(new GridLayout());
        connection = passedConnection;
    }

    private void createControlButtons() {
        Composite composite = new Composite(shell, SWT.NONE);
        composite.setLayoutData(new GridData(GridData.HORIZONTAL_ALIGN_END));
        GridLayout layout = new GridLayout();
        layout.numColumns = 2;
        composite.setLayout(layout);

        Button okButton = new Button(composite, SWT.PUSH);
        okButton.setText("OK");
        okButton.addSelectionListener(new SelectionAdapter() {
            public void widgetSelected(SelectionEvent e) {
                if(personID > 0){
                    try {
                        PreparedStatement ps = connection.prepareStatement("UPDATE person SET photo = ? " +
                                                                                              "WHERE person_id = ?");
                        ps.setBytes(1, personImage.getImageData().data);
                        ps.setInt(2, personID);
                        ps.executeUpdate();
                        ps.close();
                    } catch (SQLException err) {
                        err.printStackTrace();
                    }
                } else {
                    try {
                        PreparedStatement ps = connection.prepareStatement("INSERT INTO person (photo) VALUES (?)");
                        ps.setBytes(1, personImage.getImageData().data);
                        ps.executeUpdate();
                        ps.close();
                    } catch (SQLException err) {
                        err.printStackTrace();
                    }
                }               
                shell.close();
            }
        });

        Button cancelButton = new Button(composite, SWT.PUSH);
        cancelButton.setText("Cancel");
        cancelButton.addSelectionListener(new SelectionAdapter() {
            public void widgetSelected(SelectionEvent e) {
                shell.close();
            }
        });

        shell.setDefaultButton(okButton);
    }

    private void createTextWidgets(final Display display) {

        GridLayout gridLayout = new GridLayout();
        gridLayout.numColumns = 2;
        shell.setLayout(gridLayout);
        new Label(shell, SWT.NONE).setText("Photo:");

        personPhoto = new Canvas(shell, SWT.BORDER);
        GridData gridData = new GridData(GridData.FILL, GridData.FILL, true, true);
        gridData.widthHint = (int)photoWidth;
        gridData.heightHint = (int)photoHeight;
        gridData.verticalSpan = 5;
        gridData.horizontalSpan = 2;
        personPhoto.setLayoutData(gridData);
        personPhoto.redraw();

        personPhoto.addPaintListener(new PaintListener() {
            public void paintControl(final PaintEvent event) {
                if (personImage != null) {
                    event.gc.drawImage(personImage, 0, 0);
                }
            }
        });

        //Skip a Column
        new Label(shell, SWT.NONE);

        Button browse = new Button(shell, SWT.PUSH);
        browse.setText("Browse...");
        gridData = new GridData(GridData.FILL, GridData.CENTER, true, false);
        gridData.horizontalIndent = 5;
        browse.setLayoutData(gridData);
        browse.addSelectionListener(new SelectionAdapter() {
            public void widgetSelected(SelectionEvent event) {
                String fileName = new FileDialog(shell).open();
                if (fileName != null) {
                    personImage = new Image(display, fileName);
                    personPhoto.redraw();
                }
            }
        });

        Button delete = new Button(shell, SWT.PUSH);
        delete.setText("Delete");
        gridData = new GridData(GridData.FILL, GridData.BEGINNING, true, false);
        gridData.horizontalIndent = 5;
        delete.setLayoutData(gridData);
        delete.addSelectionListener(new SelectionAdapter() {
            public void widgetSelected(SelectionEvent event) {
                if (personImage != null) {
                    personImage.dispose();
                    personImage = null;
                    personPhoto.redraw();
                }
            }
        });

        //Skip a Column
        new Label(shell, SWT.NONE);

        //Skip two Rows
        new Label(shell, SWT.NONE);
        new Label(shell, SWT.NONE);
        new Label(shell, SWT.NONE);
        new Label(shell, SWT.NONE);     
    }

    public void open() {
        Display display = shell.getDisplay();
        //To avoid null pointer exceptions
        personImage = new Image(display,"user.png");

        try{
            PreparedStatement ps = connection.prepareStatement("SELECT photo FROM person WHERE person_id = ?");
            ps.setInt(1, personID);
            rs = ps.executeQuery();
            while (rs.next()) {
                //dispose of the current image
                personImage.dispose();
                personImage = new Image(display, (int) photoWidth, (int) photoHeight);
                //Retrieve the photo for this person
                personImage.getImageData().data = rs.getBytes("photo");
            }
            ps.close();
            rs.close();    
        } catch (SQLException e) {
            e.printStackTrace();
        }

        createTextWidgets(display);
        createControlButtons();
        shell.pack();
        shell.open();
        while(!shell.isDisposed()){
            if(!display.readAndDispatch())
                display.sleep();
        }
    }
}

Answer 1

If it were me, I wouldn't save the image into a database. Firstly due to issues like this and secondly because it will make the database quite large. It may be easier to include a path to the image in the database, and then load that image from the path. Similarly an insert would only insert the path to the image file.