how to convert image to byte array in java? [dupli

Question

This question already has an answer here:

• File to byte[] in Java 21 answers

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.

Answer 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())

Answer 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.

Answer 3

Using RandomAccessFile would be simple and handy.

RandomAccessFile f = new RandomAccessFile(filepath, "r");
byte[] bytes = new byte[(int) f.length()];
f.read(bytes);
f.close();

Answer 4

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();

Answer 5

I think the best way to do that is to first read the file into a byte array, then convert the array to an image with ImageIO.read()

Answer 6

java.io.FileInputStream is what you're looking for :-)