package com.random;

import java.util.Random;

public class RandomNum {

	public static String genRandomNum(int pwd_len) {
		final int maxNum = 36;
		int i;
		int count = 0;
		char[] str = { 'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k',
				'l', 'm', 'n', 'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w',
				'x', 'y', 'z', '0', '1', '2', '3', '4', '5', '6', '7', '8', '9' };
		StringBuffer pwd = new StringBuffer("");
		Random r = new Random();
		while (count < pwd_len) {
			i = Math.abs(r.nextInt(maxNum));

			if (i >= 0 && i < str.length) {
				pwd.append(str[i]);
				count++;
			}
		}
		return pwd.toString();
	}

	public static void main(String[] args) {
		String num = genRandomNum(10);
		System.out.println(num);
	}

}