随机生成手机号

//随机生成手机号码前3位
public static String randomPhonoNum(){
    int[] mobileStart = {139,138,137,136,135,134,159,158,157,150,151,152,188,130,131,132,156,155,133,153,189,180,177,176};
    Random r = new Random();
    ArrayList<Integer> mobileList = new ArrayList<>();
    for(int i = 0;i<mobileStart.length;i++){
        mobileList.add(mobileStart[i]);
    }

    Random r1 = new Random();
    String temp = "";
    for(int i=0;i<8;i++){
        if(i==4){
            temp += "";
        }
        temp += r1.nextInt(10);
    }
    return mobileList.get(r.nextInt(mobileList.size()))+temp;
}