how to convert image to byte array in java? [duplicate]

I want to convert an image to byte array and vice versa. Here, the user will enter the name of the image (.jpg) and program will read it from the file and will convert it to a byte array.

Solution 1:

If you are using JDK 7 you can use the following code..

import java.nio.file.Files;
import java.io.File;

File fi = new File("myfile.jpg");
byte[] fileContent = Files.readAllBytes(fi.toPath())

Solution 2:

BufferedImage consists of two main classes: Raster & ColorModel. Raster itself consists of two classes, DataBufferByte for image content while the other for pixel color.

if you want the data from DataBufferByte, use:

public byte[] extractBytes (String ImageName) throws IOException {
 // open image
 File imgPath = new File(ImageName);
 BufferedImage bufferedImage = ImageIO.read(imgPath);

 // get DataBufferBytes from Raster
 WritableRaster raster = bufferedImage .getRaster();
 DataBufferByte data   = (DataBufferByte) raster.getDataBuffer();

 return ( data.getData() );
}

now you can process these bytes by hiding text in lsb for example, or process it the way you want.

Solution 3:

File fnew=new File("/tmp/rose.jpg");
BufferedImage originalImage=ImageIO.read(fnew);
ByteArrayOutputStream baos=new ByteArrayOutputStream();
ImageIO.write(originalImage, "jpg", baos );
byte[] imageInByte=baos.toByteArray();

Solution 4:

Try this code snippet

BufferedImage image = ImageIO.read(new File("filename.jpg"));

// Process image

ImageIO.write(image, "jpg", new File("output.jpg"));

Solution 5:

Here is a complete version of code for doing this. I have tested it. The BufferedImage and Base64 class do the trick mainly. Also some parameter needs to be set correctly.

public class SimpleConvertImage {
    public static void main(String[] args) throws IOException{
        String dirName="C:\\";
        ByteArrayOutputStream baos=new ByteArrayOutputStream(1000);
        BufferedImage img=ImageIO.read(new File(dirName,"rose.jpg"));
        ImageIO.write(img, "jpg", baos);
        baos.flush();

        String base64String=Base64.encode(baos.toByteArray());
        baos.close();

        byte[] bytearray = Base64.decode(base64String);

        BufferedImage imag=ImageIO.read(new ByteArrayInputStream(bytearray));
        ImageIO.write(imag, "jpg", new File(dirName,"snap.jpg"));
    }
}

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