随机生成6位随机数（字母+数字）

package com.test;public class test {public static void main(String[] args) {String randomcode = "";// 用字符数组的方式随机String model = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ";char[] m = model.toCharArray();for (int j = 0; j < 6; j++) {char c = m[(int) (Math.random() * 36)];// 保证六位随机数之间没有重复的if (randomcode.contains(String.valueOf(c))) {j--;continue;}randomcode = randomcode + c;}System.out.println(randomcode);}}