RandomNumberUtil

public class RandomNumberUtil {     public static String getRandomNumber(){        String[] beforeShuffle = new String[] {"0","1","2","3","4","5","6","7","8","9"};         List list = Arrays.asList(beforeShuffle);         Collections.shuffle(list);        StringBuilder sb = new StringBuilder();         for (int i = 0; i < list.size(); i++) {             sb.append(list.get(i));        }        String afterShuffle = sb.toString();         return afterShuffle.substring(3, 9) ;    }    public static void main(String[] args) {        System.out.println(getRandomNumber());    }}`这里写代码片`