1.指定数字范围

package com.jiayou.peis.official.account.biz.utils;

import java.util.Random;

public class Test {
    public static void main(String[] args) {
        Random r = new Random();
        String aa="";
        for(int i = 0; i < 10000; i++){
            aa+= r.nextInt(2);//获取小于2的随机数，即0和1
        }
        System.out.println(aa);
    }
}