随机生成手机号

public class Phone {
    public static void getPhoneNum() {
        String[] Top3 = {"133", "149", "153", "173", "177",
                "180", "181", "189", "199", "130", "131", "132",
                "145", "155", "156", "166", "171", "175", "176", "185", "186", "166", "134", "135",
                "136", "137", "138", "139", "147", "150", "151", "152", "157", "158", "159", "172",
                "178", "182", "183", "184", "187", "188", "198", "170", "171"};
        //随机出真实号段   使用数组的length属性，获得数组长度，
        //通过Math.random（）*数组长度获得数组下标，从而随机出前三位的号段
        String firstNum = Top3[(int) (Math.random() * Top3.length)];
        //随机出剩下的8位数
        String lastNum = "";
        final int last = 8;
        for (int i = 0; i < last; i++) {
            //每次循环都从0~9挑选一个随机数
            lastNum += (int) (Math.random() * 10);
        }
        //最终将号段和尾数连接起来
        String phoneNum = firstNum+ lastNum;
        System.out.println(phoneNum);
    }
    

    public static  void main(String[] args) {
        //生成二十个手机号码
        int num = 20;
        System.out.println("手机号码如下：");
        for (int i = 0; i < num; i++) {
            getPhoneNum();
        }
    }

}