Question

Ideally, we would like to take a long(System.currentTimeMillis in java) plus a postfix long as well and convert it to a set of characters+numbers in a much shorter string. We only want uppercase letters used. Is there a library for this already as it would seem like a very re-usable library for generating keys that users can type in easier as they are shorter.

I guess I could always write one but it would be nice to easily just grab someone else’s code/library.

example

• 0 = 0
• 1 = 1
• 2 = 2
• the rest digits
• 11 = A
• 12 = B
• 13 = C

so I can take a number and reduce the number of digits quite significantly.

thanks,
Dean

Answer 1

Simply use this:

long l = System.currentTimeMillis();
String str = Long.toString(l, 36).toUpperCase();

To convert it back, use:

String str = "9XQ693458KF";
long = Long.parseLong(str, 36); // No need to use toLowerCase here

The 36 refers to the radix (10 digits + 26 characters).

JavaDoc references:

• Long.toString(long, int);
• Long.parseLong(String, int);