Using Java StringBuilder Formatter class

Question

I'm learning how to use java's Formatter class. I'd like to convert a positive byte to a hexadecimal number, then parse it into a String with two digits.

My method would look something like this:

String toHexString(byte byteToConvert) {
        StringBuilder hexBuilder = new StringBuilder();
        hexBuilder.append(Integer.toHexString(byteToConvert));
        return hexBuilder.toString();
}

Is there a way to be able to format the String (or the StringBuilder) to get two digits?

System.out.println(toHexString(127)); // Would like it to output "7f"
System.out.println(toHexString(1)); // Would like it to output "01"

A quick google search presents [this example](https://stackoverflow.com/questions/9610254/string-format-and-hex-numbers-in-java) and [this example](https://stackoverflow.com/questions/5258415/how-to-get-hex-value-from-integer-in-java) as possible options — MadProgrammer, Sep 24 '17 at 08:19

score 2 · Accepted Answer · answered Sep 24 '17 at 08:19

2

You don't need a StringBuilder here. Simply using String.format would do the trick:

String toHexString(byte byteToConvert) {
    return String.format("%02x", byteToConvert);
}

answered Sep 24 '17 at 08:19

Mureinik

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Using Java StringBuilder Formatter class

1 Answers1