일반 Hex string <-> String object

Question

I want to convert a Hex String to String.
Example input : "41424344"
Example output : "ABCD"

Answer

public static String hexToString(String input, int groupLength) { 

StringBuilder sb = new StringBuilder(input.length() / groupLength); 

for (int i = 0; i < input.length() - groupLength + 1; i += groupLength) { 

String hex = input.substring(i, i + groupLength); 

sb.append((char) Integer.parseInt(hex, 16)); 

}

return sb.toString(); 

}

Question

String object to Hex string

Answer

public String stringToHex(String st) {

StringBuffer sb = new StringBuffer();

for(int i = 0; i<st.length(); i++){

int ch=(int)st.charAt( i );

String hs = "00"+Integer.toHexString( ch );

sb.append(hs);

} 

return sb.toString();

}