Solved "Codes"

Hello, I was wondering if there was a way, for me to be able to generate, let's say 8 character "codes" (numbers and letters) that I could give to a player and so on and so forth. The only trouble I'm having, is

1) Actually generating a random "code"

2) Authenticating a "code" so players don't just choose random numbers and letters

Example of a code "a9w9dfq3"

Any help?

 

@darthteddy1
Lets say the codes consist of 4 letters and 2 numbers. Here's what you would do.

1. Create a collection or array of letters/numbers (If you want it to be more secure, add lower case letters and upper case letters to the letters array)
   
2. Create an instance of random
3. Create a character by using "char c1 = letters.get(random.nextInt(letters.size))"
4. Do this for all 6 chars.
5. Turn the chars into one string.

As for authenticating the code, I do not know how you would go about this. You can create a "try" counter, that after 3 times failing to guess the password, the user will no longer be allowed to enter that account.

 

http://stackoverflow.com/questions/41107/how-to-generate-a-random-alpha-numeric-string

http://stackoverflow.com/questions/5683327/how-to-generate-a-random-string-of-20-characters

 

thanks for the making a code, but to clear up for everyone, it's not for logging into accounts, it's for redeeming things

 

Code:

char[] chars = "abcdefghijklmnopqrstuvwxyz".toCharArray();
StringBuilder sb = new StringBuilder();
Random random = new Random();
for (int i = 0; i < 5; i++) {
    char c = chars[random.nextInt(chars.length)];
    sb.append(c);
}

Then just put it in a hashmap storing their uuid and the "code" see if it's the exact same then do what you want to do from there

 

@darthteddy1
org.apache.commons.lang.RandomStringUtils#randomAlphanumeric

 

That... works too I guess.

 

@darthteddy1 Use RandomStringUtils as @Assist said (It's included in the bukkit api libraries), then use a HashMap to store what item/items they receive, a HashMap to store how many attempts a player has taken (Don't add an attempt if they get it right, otherwise they can't redeem more than a set amount and clear it after an amount of time), then to validate the code you just do HashMap#containsKey(String);

 

Thanks everyone, I got it! (Saving using a Hashmap: <UUID, String>)