How to get byte[] from javafx imageView?

问题

How do i get byte[] from javafx image/imageview class? I want to store my image as a Blob into my database.This is the method that i use for it

 public PreparedStatement prepareQuery(HSQLDBConnector connector) {
        try {
            Blob logoBlob = connector.connection.createBlob();
            logoBlob.setBytes(0,logo.getImage());//stuck  here
            for (int i = 0, a = 1; i < data.length; i++, a++) {

                connector.prepStatCreateProfile.setString(a, data[i]);

            }
            //store LOB

            connector.prepStatCreateProfile.setBlob(11, logoBlob);

        } catch (SQLException ex) {
            ex.printStackTrace();
        }
        return connector.prepStatCreateProfile;
    }

Is there a way to convert from my current object (imageview),image) into byte[]?, or shoud i start to think about using other class for my image/ alternatively point to the location with reference and work with paths/urls?

回答1:

try this one:

BufferedImage bImage = SwingFXUtils.fromFXImage(logo.getImage(), null);
ByteArrayOutputStream s = new ByteArrayOutputStream();
ImageIO.write(bImage, "png", s);
byte[] res  = s.toByteArray();
s.close(); //especially if you are using a different output stream.

should work depending on the logo class

you need to specify a format while writing and reading, and as far as I remember bmp is not supported so you will end up with a png byte array on the database

回答2:

pure java fx solution trace ( == you will have to fill in missing points :)

Image i = logo.getImage();
PixelReader pr = i.getPixelReader();
PixelFormat f = pr.getPixelFormat();

WriteablePixelFromat wf = f.getIntArgbInstance(); //???

int[] buffer = new int[size as desumed from the format f, should be  i.width*i.height*4];

pr.getPixels(int 0, int 0, int i.width, i.height, wf, buffer, 0, 0);

回答3:

Lorenzo's answer is correct, this answer just examines efficiency and portability aspects.

Depending on the image type and storage requirements, it may be efficient to convert the image to a compressed format for storage, for example:

ByteArrayOutputStream byteOutput = new ByteArrayOutputStream();
ImageIO.write(SwingFXUtils.fromFXImage(fxImage, null), "png", byteOutput);
Blob logoBlob = connector.connection.createBlob();
logoBlob.setBytes(0, byteOutput.toByteArray());

Another advantage of doing a conversion to a common format like png before persisting the image is that other programs which deal with the database would be able to read the image without trying to convert it from a JavaFX specific byte array storage format.

来源：https://stackoverflow.com/questions/24038524/how-to-get-byte-from-javafx-imageview