练习题--字符判断

package com.javabin.interface_;

/**
 * Copyright (C), 2018-2021, Mr.Lin
 * Author: Mr.Lin
 * Date: 2021/11/20 1:11
 * FileName: Holloweork01
 * Description:
 */
public class Holloweork01 {
    public static void main(String[] args) {
        String name = "冯清河";
        String pwd = "1314520";
        String email = "5644@qq.4644";

        try {
            userRegister(name, pwd, email);
            System.out.println("恭喜注册成功！！！");
        } catch (Exception e) {
            System.out.println(e.getMessage());
        }
    }

    public static void userRegister(String name, String pwd, String email) {
        if (!(name != null && pwd != null && email != null)) {
            throw new RuntimeException("输入的字符不允许为空值;");
        }

        int userLength = name.length();
        if (!(userLength >= 2 && userLength <= 4)) {
            throw new RuntimeException("用户名长度要求2~4；");
        }
        if (!(pwd.length() == 7 && isDigital(pwd))) {
            throw new RuntimeException("密码长度要求长度7，密码要求位数字;");
        }

        int i = email.indexOf("@");
        int j = email.indexOf(".");
        if (!(i > 0 && j > i)) {
            throw new RuntimeException("邮箱必须包含@和. 并且.必须在@之后;");
        }

    }

    public static boolean isDigital(String str) {
        char[] chars = str.toCharArray();
        for (int i = 0; i < chars.length; i++) {
            if (chars[i] < '0' && chars[i] > '9') {
                return false;
            }
        }
        return true;
    }
}