正则表达式 练习：验证邮箱地址

https://www.bilibili.com/video/BV1Eq4y1E79W?p=24

验证电子邮件格式是否合法

规定电子邮件规则为：

1. 只能有一个@
2. @前面是用户名，可以是 a-z、A-Z、0-9、 _（下划线）、-（减号、中划线）字符
3. @后面是域名，并且域名只能是英文字母，比如 sohu.com 或者 tsinghua.org.cn

写出对应的正则表达式，验证输入的字符串是否满足规则

自己实现的

public class Homework01 {

    public static void main(String[] args) {

        String regex = "[a-zA-Z0-9_\\-]+@((\\w+\\.))+\\w+";

        Homework01 work = new Homework01();

        System.out.println("work.test1(regex) success:" + work.test1(regex));

        System.out.println("work.test2(regex) success:" + work.test2(regex));

        System.out.println("work.test3(regex) success:" + work.test3(regex));

        System.out.println("work.test4(regex) success:" + work.test4(regex));

        System.out.println("work.test5(regex) success:" + work.test5(regex));

    }


    public boolean test1(String regex) {

        String content = "jihongchang@jihongchang.top";

        return content.matches(regex);

    }

    public boolean test2(String regex) {

        String content = "jihongchang@";

        return !content.matches(regex);

    }

    public boolean test3(String regex) {

        String content = "jihongchang@jihongchang";

        return !content.matches(regex);

    }

    public boolean test4(String regex) {

        String content = "jihongchang@jihongchang.";

        return !content.matches(regex);

    }

    public boolean test5(String regex) {

        String content = "ji_hong-chang@jihongchang.top";

        return content.matches(regex);

    }

}

work.test1(regex) success:true
work.test2(regex) success:true
work.test3(regex) success:true
work.test4(regex) success:true
work.test5(regex) success:true