Add Hexidecimal Header Info to JPEG File Using Java
- by jboyd
I need to add header info to a JPEG file in order to get it to work properly when shared on some websites, I've tracked down the correct info through a lot of Hex digging, but now I'm kind of stuck trying to get it into the file. I know where in the file it needs to go, and I know how long it is, my problem is that RandomAccessFile just overwrites existing data in the file and FileOutputStream appends the data to the end. I don't want either, I want to INSERT data starting at the third byte.
My example code:
File fileToChange = new File("someimage.jpg");
byte[] i = new byte[2];
i[0] = (byte)Integer.decode("0xcc");
i[1] = (byte)Integer.decode("0xcc");
RandomAccessFile f =
new RandomAccessFile(new File("videothing.jpg"), "rw");
long aPositionWhereIWantToGo = 2;
f.seek(aPositionWhereIWantToGo); // this basically reads n bytes in the file
f.write((byte[])i);
f.close();
So this doesn't work because it overwrites, and does not insert, I can't find any way to just insert data into a file
