Reading in any file and converting to a byte array

Question

Okay what I am trying to do is to write a program that will read in any file and convert it into a int array so that I can then manipulate the values of the int array and then re-write the file. Once I get the file into an int array I want to try and compress the data with my own algorithm as well as try to write my own encryption algorithm.
What I have been looking for is code samples that essentially read in the file as a byte array and then I have been trying to convert that byte array into an int array which I could then manipulate. So does anyone have any sample code that essentially takes a file and converts it into an int array and then converts it back into a byte array and write the file. I have found code that is close but I guess I am just too new to this. Any help would be appreciated.

Answer 1

You can read a whole file into a byte array like this:File f = new File("somefile");
int size = (int) f.length();
byte[] contents = new byte[size];
DataInputStream in = new DataInputStream(
                          new BufferedInputStream(new FileInputStream(f)));
in.readFully(contents);
in.close();Note that you need to add in the proper exception handling code. You could also use RandomAccessFile instead of the DataInputStream.
Writing a byte array to a file is easier; just construct the FileOutputStream, call write on it with the byte array, and close the stream.