Java 正規表現構文の詳細

import java.util.regex.Matcher;
import java.util.regex.Pattern;

public class EmailValidator {
    private static final String EMAIL_REGEX = "^[\w-]+(\.[\w-]+)*@[\w-]+(\.[\w-]+)+$";

    public static boolean validateEmail(String email) {
        Pattern pattern = Pattern.compile(EMAIL_REGEX);
        Matcher matcher = pattern.matcher(email);
        return matcher.matches();
    }

    public static void main(String[] args) {
        String[] emails = {"abc@163.com", "xyz@gmail.com", "invalidemail", "123456"};

        for (String email : emails) {
            System.out.println(email + ": " + validateEmail(email));
        }
    }
}

import java.util.regex.Matcher;
import java.util.regex.Pattern;

public class URLParser {
    private static final String URL_REGEX = "^(https?)://([\w-]+\.)+[\w-]+(/[\w-./?%&=]*)?$";

    public static void parseURL(String url) {
        Pattern pattern = Pattern.compile(URL_REGEX);
        Matcher matcher = pattern.matcher(url);
        if (matcher.matches()) {
            System.out.println("Protocol: " + matcher.group(1));
            System.out.println("Hostname: " + matcher.group(2));
            System.out.println("Path: " + matcher.group(3));
        } else {
            System.out.println("Invalid URL format");
        }
    }

    public static void main(String[] args) {
        String[] urls = {"http://www.example.com/path/to/page.html", "https://www.example.com/", "invalidurl"};

        for (String url : urls) {
            System.out.println("URL: " + url);
            parseURL(url);
            System.out.println();
        }
    }
}