hexa encoder decoder taken from the web

hexa.java

import java.io.UnsupportedEncodingException;


public class Hexa {
	public static void main(String[] args)  {
		//		System.out.println(h.encode("Test").toString());
		//		System.out.println(h.decode("79616c7").toString());
		System.out.println(encode("toto"));
		System.out.println(encode("★"));
		System.out.println(decode("746f746f"));
		System.out.println(decode("e29885"));

	}
	static private final int  BASELENGTH   = 128;
	static private final int  LOOKUPLENGTH = 16;
	static final private byte [] hexNumberTable    = new byte[BASELENGTH];
	static final private char [] lookUpHexAlphabet = new char[LOOKUPLENGTH];


	static {
		for (int i = 0; i < BASELENGTH; i++ ) {
			hexNumberTable[i] = -1;
		}
		for ( int i = '9'; i >= '0'; i--) {
			hexNumberTable[i] = (byte) (i-'0');
		}
		for ( int i = 'F'; i>= 'A'; i--) {
			hexNumberTable[i] = (byte) ( i-'A' + 10 );
		}
		for ( int i = 'f'; i>= 'a'; i--) {
			hexNumberTable[i] = (byte) ( i-'a' + 10 );
		}

		for(int i = 0; i<10; i++ ) {
			lookUpHexAlphabet[i] = (char)('0'+i);
		}
		for(int i = 10; i<=15; i++ ) {
			lookUpHexAlphabet[i] = (char)('A'+i -10);
		}
	}

	public static String encode(String input, String charsetName)  {
		if (input == null) throw new NullPointerException();
		try {
			return asHex(input.getBytes(charsetName));
		} catch (UnsupportedEncodingException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
			return null;
		}

	}
	public static String encode(String input)  {
		String charsetName = "UTF-8";
		if (input == null) throw new NullPointerException();
		try {
			return asHex(input.getBytes(charsetName));
		} catch (UnsupportedEncodingException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
			return null;
		}
	}



	private static String asHex(byte[] buf)
	{
		char[]  HEX_CHARS = "0123456789abcdef".toCharArray();
		char[] chars = new char[2 * buf.length];
		for (int i = 0; i < buf.length; ++i)
		{
			chars[2 * i] = HEX_CHARS[(buf[i] & 0xF0) >>> 4];
			chars[2 * i + 1] = HEX_CHARS[buf[i] & 0x0F];
		}
		return new String(chars);
	}



	public static String decode(String hexa)
	{
		for (int i=0;i < hexa.length();i++)
		{
			String codehex = hexa.substring(i) + hexa.substring(i++) ;

		}
		int lengthData = hexa.length();
		if (lengthData % 2 != 0)
			return null;

		char[] binaryData = hexa.toCharArray();
		int lengthDecode = lengthData / 2;
		byte[] decodedData = new byte[lengthDecode];
		byte temp1, temp2;
		char tempChar;
		for( int i = 0; i<lengthDecode; i++ ){
			tempChar = binaryData[i*2];
			temp1 = (tempChar < BASELENGTH) ? hexNumberTable[tempChar] : -1;
			if (temp1 == -1)
				return null;
			tempChar = binaryData[i*2+1];
			temp2 = (tempChar < BASELENGTH) ? hexNumberTable[tempChar] : -1;
			if (temp2 == -1)
				return null;
			decodedData[i] = (byte)((temp1 << 4) | temp2);
		}
		String retour =new String(decodedData);
		return retour;



	}
}