Java随机密码生成器

    public static String randomPassword(int num) {
        char[] password = new char[num];
        Random rand = new Random();
        //在ASCII码表中,48-57:数字, 65-90:大写字母, 97-122:小写字母, 33-47: 特殊符号
        for (int i = 0; i < password.length; i++) {
            int choice = rand.nextInt(4);
            int lowercase = rand.nextInt(26) + 65;
            int uppercase = rand.nextInt(26) + 97;
            int figure = rand.nextInt(10) + 48;
            int special = rand.nextInt(15) + 33;
            //将 " 和 ' 替换成#
            if (special == 34 || special == 39) {
                special = 35;
            }
            //从大写字母.小写字母.数字.特殊字符中随机取值
            switch (choice) {
                case 0:
                    password[i] = (char) lowercase;
                    break;
                case 1:
                    password[i] = (char) uppercase;
                    break;
                case 2:
                    password[i] = (char) figure;
                    break;
                case 3:
                    password[i] = (char) special;
                    break;
                default:
            }
        }
        return new String(password);
    }