Hàm - Chuyễn từ Hex qua String

 public String convertHexToString(String hex){

   StringBuilder sb = new StringBuilder();
   StringBuilder temp = new StringBuilder();
   
   //49204c6f7665204a617661 split into two characters 49, 20, 4c...
   for( int i=0; i<hex.length()-1; i+=2 ){
    
       //grab the hex in pairs
       String output = hex.substring(i, (i + 2));
       //convert hex to decimal
       int decimal = Integer.parseInt(output, 16);
       //convert the decimal to character
       sb.append((char)decimal);
    
       temp.append(decimal);
   }
   System.out.println("Decimal : " + temp.toString());
   
   return sb.toString();
  }