Java: File to Hex?

hex, java

Solution

You're in luck. I had to do this a couple months ago. Here's a dumbed-down version that takes two parameters from the command line. Both comand line parameters are filenames...the first is the input file and the second is the output file. The input file is read in binary and the output file is written as ASCII hex. Hopefully you can just adapt this to your needs.

import java.io.BufferedWriter;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileWriter;
import java.io.IOException;

public class BinToHex
{
    private final static String[] hexSymbols = { "0", "1", "2", "3", "4", "5", "6", "7", "8", "9", "a", "b", "c", "d", "e", "f" };

    public final static int BITS_PER_HEX_DIGIT = 4;

    public static String toHexFromByte(final byte b)
    {
        byte leftSymbol = (byte)((b >>> BITS_PER_HEX_DIGIT) & 0x0f);
        byte rightSymbol = (byte)(b & 0x0f);

        return (hexSymbols[leftSymbol] + hexSymbols[rightSymbol]);
    }

    public static String toHexFromBytes(final byte[] bytes)
    {
        if(bytes == null || bytes.length == 0)
        {
            return ("");
        }

        // there are 2 hex digits per byte
        StringBuilder hexBuffer = new StringBuilder(bytes.length * 2);

        // for each byte, convert it to hex and append it to the buffer
        for(int i = 0; i < bytes.length; i++)
        {
            hexBuffer.append(toHexFromByte(bytes[i]));
        }

        return (hexBuffer.toString());
    }

    public static void main(final String[] args) throws IOException
    {
        try
        {
            FileInputStream fis = new FileInputStream(new File(args[0]));
            BufferedWriter fos = new BufferedWriter(new FileWriter(new File(args[1])));

            byte[] bytes = new byte[800];
            int value = 0;
            do
            {
                value = fis.read(bytes);
                fos.write(toHexFromBytes(bytes));

            }while(value != -1);

            fos.flush();
            fos.close();
        }
        catch(Exception e)
        {
            e.printStackTrace();
        }
    }
}

Problem

Original source