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：
- 只能有一个@
- @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
- @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 = "[\\w-]+@([a-zA-Z]+\\.)+[a-zA-Z]+";
Homework01 work = new Homework01();
String content = "jihongchang@jihongchang.top";
System.out.printf("\"%s\".matches(regex):%b \n", content, content.matches(regex));
content = "jihongchang@";
System.out.printf("\"%s\".matches(regex):%b \n", content, content.matches(regex));
content = "jihongchang@jihongchang";
System.out.printf("\"%s\".matches(regex):%b \n", content, content.matches(regex));
content = "jihongchang@jihongchang.";
System.out.printf("\"%s\".matches(regex):%b \n", content, content.matches(regex));
content = "ji_hong-chang@jihongchang.top";
System.out.printf("\"%s\".matches(regex):%b \n", content, content.matches(regex));
content = "ji_hong-chang@jihongchang.@jihongchang.top";
System.out.printf("\"%s\".matches(regex):%b \n", content, content.matches(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);
}
public boolean test6(String regex) {
String content = "ji_hong-chang@jihongchang.@jihongchang.top";
return content.matches(regex);
}
}
"jihongchang@jihongchang.top".matches(regex):true
"jihongchang@".matches(regex):false
"jihongchang@jihongchang".matches(regex):false
"jihongchang@jihongchang.".matches(regex):false
"ji_hong-chang@jihongchang.top".matches(regex):true
"ji_hong-chang@jihongchang.@jihongchang.top".matches(regex):false
注意：String matches 是整体匹配