CODEWITHSUNDEEP
javamysqlimageswingblob
user3151426
user3151426

Reputation:

Reading an image from Mysql DB and resend it again to DB in Java

I have problem with the writing image again to the database ! This what I do ! The user choose an image from the hard disk through a Jframe, I read the content of the image and then I send it to the database , here I don't have any problem ! The problem when the user open a Jframe again to edit something else ! I know it maybe vague for you if you don't see the whole code ! I know how can I read a file and then encode it into hex code to send it to the database - blob data type in mysql - this my code about reading an image and convert it to hex code: this works perfectly and I have no problems with it 

 private String makeBlob(String paths) {
    char[] hexArray = "0123456789abcdef".toCharArray();
    Path path = Paths.get(paths);

    byte[] bytes = null;
    try {
        bytes = Files.readAllBytes(path);
    } catch (IOException ex) {
        Logger.getLogger(LuggageAdd.class.getName()).log(Level.SEVERE, null, ex);
    }

    char[] hexChars = new char[bytes.length * 2];

    for (int j = 0; j < bytes.length; j++) {
        int v = bytes[j] & 0xFF;
        hexChars[j * 2] = hexArray[v >>> 4];
        hexChars[j * 2 + 1] = hexArray[v & 0x0F];
    }
    String test = new String(hexChars);
    return "0x" + test;
}

Note : the image is displayed using a jLabel on my jFrame ! so it's imageIcon

Is there is way to do the same thing with an existed image object ! I mean, here above I generate a hex code from a file (PATH TO AN IMAGE ), but I want to generate a hex code from an existing imageIcon object ?? If I can do that it will be easy to resend the image again to the database if it has not been edited !

Here is how I get a image from the data base : 

   public ImageIcon getImage(int id) {
    BufferedImage bufferedImage = null;
    try {
        String ss = "SELECT image FROM  luggage WHERE ID = " + id + " ";
        ResultSet result = this.databaseConnection.doQuery(ss);

        while (result.next()) {
            Blob blob = result.getBlob("image");

            int blobLength = (int) blob.length();

            byte[] blobAsBytes = blob.getBytes(1, blobLength);
            bufferedImage = ImageIO.read(new ByteArrayInputStream(blobAsBytes));
        }
    } catch (Exception ex) {
        ex.printStackTrace();   }

    return new ImageIcon(bufferedImage.getScaledInstance(128, 128, Image.SCALE_SMOOTH));
}

PS: I have tried an another solution, I read the image and the write it temporarily to a hard disk and then rewrite it again to the data base, but the problem that the size of the image increased when I saved it to the disk! if the original image size is 1.9MB then it will be 2.40MB . That's not efficient because, I want to re-save my image with same quality and size, beside that I have a limit of size of an image.

So the only way to solve it is know how I can get the content of an image icon and resend it again to the data base !

Thanks :)

Upvotes: 0

Views: 307

Answers (1)

StanislavL
StanislavL

Reputation: 57381

You can either store the image blob (of the blobAsBytes) reference as source of the image.

Or

use ImageIcon's method getImage() and convert the image to bytes.

E.g.

try {
    // retrieve image
    BufferedImage bi = getMyImage();
    File outputfile = new File("saved.png");
    ImageIO.write(bi, "png", outputfile);
} catch (IOException e) {
    ...
}

or save not to file but to ByteArrayOutputStream.

But for me the first way is better because the ImageIcon keeps scled instance instead of original image.

Upvotes: 1

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