如何在Spring WebClient请求之间保存cookies？

import org.springframework.http.HttpHeaders;
import org.springframework.http.MediaType;
import org.springframework.web.reactive.function.client.ClientHttpConnector;
import org.springframework.web.reactive.function.client.ExchangeFilterFunction;
import org.springframework.web.reactive.function.client.WebClient;
import reactor.core.publisher.Mono;

import java.util.HashMap;
import java.util.Map;

public class WebClientCookiesExample {

    public static void main(String[] args) {
        // 创建一个WebClient实例
        WebClient webClient = WebClient.builder()
                .clientConnector(new ReactorClientHttpConnector())
                .filter(addCookies())
                .build();

        // 第一次请求，获取cookies
        Mono<String> firstResponse = webClient.get()
                .uri("https://example.com/login")
                .retrieve()
                .bodyToMono(String.class);

        // 假设第一次请求后，我们从响应中获取了cookies
        String cookies = extractCookiesFromResponse(firstResponse.block());

        // 第二次请求，使用之前获取的cookies
        Mono<String> secondResponse = webClient.get()
                .uri("https://example.com/user/profile")
                .header(HttpHeaders.COOKIE, cookies)
                .retrieve()
                .bodyToMono(String.class);

        System.out.println(secondResponse.block());
    }

    private static ExchangeFilterFunction addCookies() {
        return ExchangeFilterFunction.ofRequestProcessor(clientRequest -> {
            // 从某个地方获取cookies，例如从数据库或缓存
            String cookies = getCookiesFromSomewhere();
            if (cookies != null) {
                clientRequest = clientRequest.header(HttpHeaders.COOKIE, cookies);
            }
            return Mono.just(clientRequest);
        });
    }

    private static String extractCookiesFromResponse(String response) {
        // 实现从响应中提取cookies的逻辑
        // 这里只是一个示例，实际应用中需要解析响应头
        return "sessionid=123456";
    }

    private static String getCookiesFromSomewhere() {
        // 实现从某处获取cookies的逻辑
        return null;
    }
}