如何使用Java 11 HTTP客户端进行抢占式身份验证？

import java.net.Authenticator;
import java.net.PasswordAuthentication;
import java.net.URI;
import java.net.http.HttpClient;
import java.net.http.HttpRequest;
import java.net.http.HttpResponse;

Authenticator authenticator = new Authenticator() {
    @Override
    protected PasswordAuthentication getPasswordAuthentication() {
        return new PasswordAuthentication("username", "password".toCharArray());
    }
};

Authenticator.setDefault(authenticator);

HttpClient client = HttpClient.newBuilder().build();

HttpRequest request = HttpRequest.newBuilder()
        .uri(URI.create("https://example.com"))
        .build();

HttpResponse<String> response = client.send(request, HttpResponse.BodyHandlers.ofString());

System.out.println(response.statusCode());
System.out.println(response.body());