Convert character to ASCII numeric value in java

I have String name = "admin";
then I do String charValue = name.substring(0,1); //charValue="a"

I want to convert the charValue to its ASCII value (97), how can I do this in java?

Solution 1:

Very simple. Just cast your char as an int.

char character = 'a';    
int ascii = (int) character;

In your case, you need to get the specific Character from the String first and then cast it.

char character = name.charAt(0); // This gives the character 'a'
int ascii = (int) character; // ascii is now 97.

Though cast is not required explicitly, but its improves readability.

int ascii = character; // Even this will do the trick.

Solution 2:

just a different approach

    String s = "admin";
    byte[] bytes = s.getBytes("US-ASCII");

bytes[0] will represent ascii of a.. and thus the other characters in the whole array.

Solution 3:

Instead of this:

String char = name.substring(0,1); //char="a"

You should use the charAt() method.

char c = name.charAt(0); // c='a'
int ascii = (int)c;

Solution 4:

The several answers that purport to show how to do this are all wrong because Java characters are not ASCII characters. Java uses a multibyte encoding of Unicode characters. The Unicode character set is a super set of ASCII. So there can be characters in a Java string that do not belong to ASCII. Such characters do not have an ASCII numeric value, so asking how to get the ASCII numeric value of a Java character is unanswerable.

But why do you want to do this anyway? What are you going to do with the value?

If you want the numeric value so you can convert the Java String to an ASCII string, the real question is "how do I encode a Java String as ASCII". For that, use the object StandardCharsets.US_ASCII.