Extract and convert blob field in image. MySQL - Java [closed] - java

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I am writing a java program for fingerprint recognition, and I insert the fingerprint image in the MySQL database( in a field blob), but now is the problem.
How do I go back to the image of the fingerprint? where I have to print it?( I presume in a canvas). help me please is very important, thanks to all.

The blob is a array of bytes, so is the Image.
So
img -> read bytes -> store as blob
vs
blob -> read bytes -> store as img

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How to read PSD format image by Java? [closed]

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I am developing a java swing based application which show thumbnail of any format(jpg,png) images. For that, at first I read the image file by ImageIO.read(file name) and then create thumbnail of it. But it shows null pointer exception when read PSD format file.
I use ideli library for read PSD type file but it requires subcription/paid. So there have any free library to read PSD type file in Java?
image = ImageIO.read(new File(i));
thumb = Thumbnails.of(image).size(140,100).outputFormat("png").asBufferedImage();
ImageIO.write(thumb, "png", new File("thumb.png"));
By above code, I can read (without PSD) image file and create thumbnail of image.
Have a read of the documentation, PSD is not a supported format.
You might find some value from a similar question here.

Writing a list to a file and reading from it [closed]

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I have looked around but have not been able to find anything related. I have 3 Lists (week, day, period) I need to write them to a file so that they are not deleted when the app is closed. How would I write these lists to a file and then when the app is open read them back into a List as they were before. Not sure if this is a stupid question.
You can find some examples in the android doc.
Basically, you can use File like in Java, for example to write (from android doc):
String FILENAME = "hello_file";
String string = "hello world!";
FileOutputStream fos = openFileOutput(FILENAME, Context.MODE_PRIVATE);
fos.write(string.getBytes());
fos.close();

MySQL BLOB Default Value [closed]

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how to clear blob column cell in MySQL without remove complete row in the data table and what is the default value in MySQL blob data type ?
From 11.4.3. The BLOB and TEXT Types:
BLOB and TEXT columns cannot have DEFAULT values.
Thus, if the column is NULLABLE then NULL is the default; otherwise there is no default value. (Although, at the application level, a blob of length=0 might be a sensible "default".)

How to convert Grayscale image to Color in Java? [closed]

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Could you point me in the right direction to find a tutorial on how to convert a grayscale image to it's original colors? Is this even possible?
I've tried using BufferedImage and applying a function to the RGB values by bitshifting them 8 bits to the left and isolating the reds, but, of course, there are no reds that are found, as it is grayscale.
I'd really appreciate a push in the right direction!
"Is this even possible?" -- No, not a prayer's chance in Hades. Once you have a grayscale image, all color information is gone.

How to create a suggestion box [closed]

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I was developing an java swing application to add view and modify the list of medicines.While adding the medicines it should show the list from the database(like google search box).For example if we press "p" it should show 'paracetamol' from the database.
You should implement a change listener on the text input box, when the text is changed, run a query to the database with the contents of the input box.

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