public class StringToHex{
 
  public String convertStringToHex(String str){
 
	  char[] chars = str.toCharArray();
 
	  StringBuffer hex = new StringBuffer();
	  for(int i = 0; i < chars.length; i++){
	    hex.append(Integer.toHexString((int)chars[i]));
	  }
 
	  return hex.toString();
  }
 
  public String convertHexToString(String hex){
 
	  StringBuilder sb = new StringBuilder();
	  StringBuilder temp = new StringBuilder();
 
	  //49204c6f7665204a617661 се превръща в двучислен 49, 
	  for( int i=0; i<hex.length()-1; i+=2 ){
 
	      //Взима hex по двойки
	      String output = hex.substring(i, (i + 2));
	      //Превръща hex в decimal
	      int decimal = Integer.parseInt(output, 16);
	      //Превръща decimal в character
	      sb.append((char)decimal);
 
	      temp.append(decimal);
	  }
	  System.out.println("Decimal : " + temp.toString());
 
	  return sb.toString();
  }
 
  public static void main(String[] args) {
 
	  StringToHex strToHex = new StringToHex();
	  System.out.println("\n***** Convert ASCII to Hex *****");
	  String str = "I Love Java!";  
	  System.out.println("Original input : " + str);
 
	  String hex = strToHex.convertStringToHex(str);
 
	  System.out.println("Hex : " + hex);
 
	  System.out.println("\n***** Convert Hex to ASCII *****");
	  System.out.println("Hex : " + hex);
	  System.out.println(
"ASCII : " + strToHex.convertHexToString(hex));
  }
}