Spring 6/Spring Boot 3 HTTP 接口中的重试机制实现

public interface TodoClient {
    @GetExchange("/todos/{id}")
    Mono<Todo> getTodo(@PathVariable String id);
}

WebClient webClient = WebClient.builder().baseUrl("http://localhost:8080").build();
HttpServiceProxyFactory factory = HttpServiceProxyFactory.builder(WebClientAdapter.forClient(webClient)).build();
TodoClient todoClient = factory.createClient(TodoClient.class);

public Mono<String> getData(String stockId) {
    return webClient.get()
        .uri("/data/{id}", stockId)
        .retrieve()
        .bodyToMono(String.class)
        .retryWhen(Retry.backoff(3, Duration.ofSeconds(2)));
}

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.reactive.function.client.ClientResponse;
import org.springframework.web.reactive.function.client.ExchangeFilterFunction;
import org.springframework.web.reactive.function.client.WebClient;
import org.springframework.web.reactive.function.client.support.WebClientAdapter;
import org.springframework.web.service.invoker.HttpServiceProxyFactory;
import reactor.core.publisher.Mono;
import reactor.util.retry.Retry;

import java.time.Duration;

@Configuration
public class HttpClientConfig {

    private static final Logger log = LoggerFactory.getLogger(HttpClientConfig.class);

    /**
     * 定义一个重试过滤器
     * 该过滤器会在请求失败（HTTP 错误状态码）时触发重试
     *
     * @return ExchangeFilterFunction 实例
     */
    @Bean
    public ExchangeFilterFunction retryFilter() {
        return (request, next) ->
            next.exchange(request) // 执行实际的HTTP请求
                .flatMap(clientResponse ->
                    Mono.just(clientResponse)
                        .filter(response -> clientResponse.statusCode().isError()) // 检查响应是否为错误状态码
                        .flatMap(ClientResponse::createException) // 如果是错误，则创建并抛出WebClientResponseException
                        .flatMap(Mono::error) // 将异常包装成Mono.error()，以便retryWhen捕获
                        .thenReturn(clientResponse) // 如果不是错误，则直接返回响应
                )
                .retryWhen(
                    Retry.fixedDelay(3, Duration.ofSeconds(30)) // 配置重试策略：固定延迟30秒，重试3次
                        .doAfterRetry(retrySignal -> log.warn("HTTP请求失败，正在进行第 {} 次重试...", retrySignal.totalRetriesInARow() + 1))
                        .onRetryExhaustedThrow((retryBackoffSpec, retrySignal) -> {
                            log.error("HTTP请求重试次数耗尽，总计重试 {} 次。", retrySignal.totalRetriesInARow());
                            return retrySignal.failure(); // 重试耗尽后抛出原始异常
                        })
                );
    }

    /**
     * 配置并创建 TodoClient 实例，集成重试过滤器
     *
     * @return TodoClient 实例
     */
    @Bean
    public TodoClient todoClient(WebClient.Builder webClientBuilder) {
        WebClient webClient = webClientBuilder
            .baseUrl("http://localhost:8080") // 替换为你的服务基础URL
            .filter(retryFilter()) // 将重试过滤器添加到WebClient
            .build();

        HttpServiceProxyFactory factory =
            HttpServiceProxyFactory.builder(WebClientAdapter.forClient(webClient)).build();
        return factory.createClient(TodoClient.class);
    }
}

@Bean
public TodoClient todoClient(WebClient.Builder webClientBuilder) {
    WebClient webClient = webClientBuilder
        .baseUrl("http://localhost:8080") // 替换为你的服务基础URL
        .filter(retryFilter()) // 将重试过滤器添加到WebClient
        .build();

    HttpServiceProxyFactory factory =
        HttpServiceProxyFactory.builder(WebClientAdapter.forClient(webClient)).build();
    return factory.createClient(TodoClient.class);
}