[java] Convert bytes, hex, hex string, string

String inputString = "Hello World!!"; System.out.println("input String :" + inputString); //string -> byte array byte[] inputBytes = inputString.getBytes(); String hexString = ""; for (byte b : inputBytes) { hexString += Integer.toString((b & 0xF0) >> 4, 16); hexString += Integer.toString(b & 0x0F, 16); } System.out.println("hex String :" + hexString); //hex string -> byte array byte[] bytes = new java.math.BigInteger(hexString, 16).toByteArray(); System.out.println("byte Array :" + bytes); //byte array -> hex string String hexStrin2 = new java.math.BigInteger(bytes).toString(16); System.out.println("hex String :" + hexStrin2); //hex string -> string byte [] hexBytes = new byte [hexStrin2.length() / 2]; int j = 0; for (int i = 0; i < hexStrin2.length(); i += 2) { hexBytes[j++] = Byte.parseByte(hexStrin2.substring(i, i + 2), 16); } String hr = new String(hexBytes); System.out.println("input String :" + hr);