写一个Java的白名单过滤

import java.util.ArrayList;
import java.util.List;

public class WhitelistFilter {

private List<String> whitelist;

public WhitelistFilter() {
this.whitelist = new ArrayList<>();
}

public void add(String url) {
this.whitelist.add(url);
}

public boolean isAllowed(String url) {
for (String allowedUrl : this.whitelist) {
if (url.startsWith(allowedUrl)) {
return true;
}
}
return false;
}

public static void main(String[] args) {
WhitelistFilter filter = new WhitelistFilter();
filter.add("http://www.example.com");
filter.add("https://www.example.com");
filter.add("http://subdomain.example.com");

String url1 = "http://www.example.com/index.html";
String url2 = "https://www.example.com/about.html";
String url3 = "http://www.example.org/index.html";

System.out.println(filter.isAllowed(url1)); // true
System.out.println(filter.isAllowed(url2)); // true
System.out.println(filter.isAllowed(url3)); // false
}
}