Java Hex Calculate toHexFromBytes(final byte[] bytes)

Description

Takes the given input and returns a String containing the hex representation of the bytes.

License

Open Source License

Parameter

Parameter	Description
bytes	byte[] the bytes to be converted

Return

String the hex conversion of the bytes (2 * bytes.length characters), and empty String if a null array is passed

Declaration

public static String toHexFromBytes(final byte[] bytes)

Method Source Code

//package com.java2s;
//License from project: Open Source License 

public class Main {
    /** Allowable hex values */
    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;

    /**//w w  w .  ja  v a2s . com
     * Takes the given input and returns a String containing the hex representation of the bytes.
     *
     * @param bytes
     *            byte[] the bytes to be converted
     *
     * @return String the hex conversion of the bytes (2 * bytes.length characters), and empty String if a null array is passed
     *
     */
    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());
    }

    /**
     * Takes the given input and returns a String containing the hex representation of the bytes.
     *
     * @param bytes
     *            byte[] the bytes to be converted
     * @param offset starting offset into the byte array
     * @param length number of bytes to convert
     * 
     * @return String the hex conversion of the bytes (2 * length characters), and empty String if a null array is passed
     *
     */
    public static String toHexFromBytes(final byte[] bytes, int offset, int length) {
        if (bytes == null || bytes.length == 0) {
            return ("");
        }

        if (offset > bytes.length || offset + length > bytes.length) {
            throw new IllegalArgumentException("Offset/length combination exceeds length of input byte array");
        }

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

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

        return (hexBuffer.toString());
    }

    /**
     * Takes the given input and returns a String containing the hex representation of the byte.
     *
     * @param b
     *            byte the byte to be converted
     *
     * @return String the hex conversion of the byte (2 characters)
     */
    public static String toHexFromByte(final byte b) {
        // need to and the shift result as java maintains the
        // sign bit and puts it back after the shift
        byte leftSymbol = (byte) ((b >>> BITS_PER_HEX_DIGIT) & 0x0f);
        byte rightSymbol = (byte) (b & 0x0f);

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