how to generate randomly UNIQUE alphanumric number which are 6 / 8 digit

Question

I'm sorry this might be duplicated post, but i really not understand how can i do this. In my system I need to generate a code(coupon) which are alphanumeric around 6 - 8 value, and if user key simply key in the code which is not under generated code(coupon) it will show error message.

i saw alot of ppl using, but i failed to applied this during import the import java.util.UUID;

String uniqueID = UUID.randomUUID().toString(); //UUID method

What i have done so far only can generate a random number ( not expected result)

Javascript

var keylist="abcdefghijklmnopqrstuvwxyz123456789";
var temp="";
function generatecoupon(plength){
temp = "";

for (i=0;i<plength;i++)
    temp+=keylist.charAt(Math.floor(Math.random()*keylist.length));

return temp;
}

function populateform(enterlength){
   document.mainfrm.COUPON.value=generatecoupon(enterlength);
}

html

<input type="button" value="Generate Coupon" onClick="populateform(this.form.thelength.value)">
<input type="hidden" name="thelength" size=3 value="6">     
<input name="COUPON" type="text" id="COUPON" size="20" maxlength="20">

Need a guide in java code to generated random unique code and checked if the value key in if out of the generated value will show error message , Please any help would be appreciated

i know, that's why i need guide from java instead of javascript — user3835327, May 18 '15 at 07:52
As you mentioned UUID - never ever use them and then cut them down a certain length to use them as ID: http://blogs.msdn.com/b/oldnewthing/archive/2008/06/27/8659071.aspx — hamena314, May 18 '15 at 08:30
Hi @hamena314 may i know why when i import `java.util.UUID;` ,system will underlined the code as cannot be resolved? — user3835327, May 18 '15 at 08:48
just normal import put inside java file.. `package com.rexit.easc;import java.util.*;import java.util.UUID;` do i need to import any library? — user3835327, May 18 '15 at 08:52
Actually not, your import seems fine. Are you using this in a java environment? Like Eclipse or something? This wont work for javascript. — hamena314, May 18 '15 at 09:04
I guess it's due to my JDK compilation level is 1.5 not supported. Is ok , i try search around. Thanks for your time @hamena314 — user3835327, May 18 '15 at 09:18

MrSimpleMind · Answer 1 · 2015-05-18T07:55:49.337

0

I was looking for something similar a short time ago. I wanted something like youtube id, and came across some good sites:

Take a look at: Hashids.org (see demo here)

also very good reading for this kind of solution, take a look at: Blogg - Create Youtube-Like IDs With PHP/Python/Javascript/Java/SQL

edited May 18 '15 at 07:55

answered May 18 '15 at 07:50

MrSimpleMind

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Hi do you have other solution ? that's more specific ? – user3835327 May 18 '15 at 08:31

score 0 · Answer 2 · answered May 18 '15 at 08:01

You should replace:

document.mainfrm.COUPON.value=generatecoupon(enterlength);
// Uncaught TypeError: Cannot read property 'COUPON' of undefined

with:

document.getElementById("COUPON").value=generatecoupon(enterlength);

You missed this but your code works.

Here a demo: http://jsfiddle.net/zL1jz9c5/

how to generate randomly UNIQUE alphanumric number which are 6 / 8 digit

Javascript

html

2 Answers2