Convert Integer to Hex in Java

Question

I want to convert an hex to int and back again.

Hex to int:

String input = "˜";
char charValue = new String(input.getBytes(), "ISO-8859-1").charAt(0);
int intValue = (int) charValue; //=152
String hexString = Integer.toHexString(intValue); //=98

Is it possible to get the ˜ back again?

Answer 1

The ˜ isn't a tilde, it is character with unicode 732.

When you convert it to a byte[], you get two bytes if you use UTF-8, -53 and -100

However if you ignore the second one and convert it to a char you get 152 (which is -53 & 0xFF)

You have a number of lossy transformations which makes it impossible to reverse them.

What you can do is convert the character to hexadecimal and back again.

String input = "˜";
String hex = DatatypeConverter.printHexBinary(input.getBytes("UTF-16BE"));
System.out.println("hex: "+hex);
String input2 = new String(DatatypeConverter.parseHexBinary(hex), "UTF-16BE");
System.out.println("input2: "+input2);

prints

hex: 02DC
input2: ˜

This will work for arbitrary Strings (of less than half a billion characters)