package com.cloud.stagging.lhcloudzuul;

 import java.util.Random;

 /**

  * 1、生成一个随机四位数，每位数字不重复。

  */

 public class demo001image {

     public static void main(String[] args) {

         generateNum();

     }

     private static void generateNum() {

         Random random = new Random();

         int[] arr = {0, 0, 0, 0, 0, 0, 0, 0, 0, 0};

         StringBuffer stringBuffer = new StringBuffer();

         int tmp = 0;

         while (stringBuffer.length() < 4) {

             tmp = random.nextInt(10);//0-9的随机数

             if (arr[tmp] == 0) {

                 stringBuffer.append(tmp);

                 arr[tmp] = 1;

             }

         }

         System.out.println(stringBuffer);

     }

 }