Spring 6 HTTP 接口中的重试机制实现指南

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

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.web.reactive.function.client.ClientResponse;
import org.springframework.web.reactive.function.client.ExchangeFilterFunction;
import reactor.core.publisher.Mono;
import reactor.util.retry.Retry;

import java.time.Duration;

public class RetryFilterConfig {

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

    // ... 其他配置或客户端 bean ...

    public ExchangeFilterFunction retryFilter() {
        return (request, next) ->
            next.exchange(request) // 执行原始请求
                .flatMap(clientResponse -> {
                    // 检查响应状态码是否为错误
                    if (clientResponse.statusCode().isError()) {
                        // 如果是错误，则创建一个异常并将其作为错误信号传播
                        // 这是关键一步，让 retryWhen 能够捕获到错误并触发重试
                        return clientResponse.createException()
                            .flatMap(Mono::error);
                    }
                    // 如果不是错误，则直接返回响应
                    return Mono.just(clientResponse);
                })
                .retryWhen(
                    // 配置重试策略
                    Retry.fixedDelay(3, Duration.ofSeconds(30)) // 固定延迟30秒，重试3次
                        .doAfterRetry(retrySignal -> log.warn("检测到错误，正在进行第 {} 次重试...", retrySignal.totalRetriesInARow() + 1)) // 每次重试后记录日志
                        .filter(throwable -> {
                            // 可选：根据异常类型决定是否重试
                            // 例如，只对 IOException 或特定的 WebClientResponseException 进行重试
                            // return throwable instanceof WebClientResponseException;
                            return true; // 默认对所有错误进行重试
                        })
                );
    }
}

import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.reactive.function.client.WebClient;
import org.springframework.web.reactive.function.client.support.WebClientAdapter;
import org.springframework.web.service.invoker.HttpServiceProxyFactory;

@Configuration
public class HttpClientConfig {

    // 假设 TodoClient 是你的 HTTP 接口
    // public interface TodoClient { ... }

    @Bean
    public TodoClient todoClient(RetryFilterConfig retryFilterConfig) { // 注入 RetryFilterConfig
        WebClient webClient =
            WebClient.builder()
                .baseUrl("http://localhost:8080") // 你的服务基础URL
                .filter(retryFilterConfig.retryFilter()) // 注册重试过滤器
                .build();

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

    // 将 RetryFilterConfig 声明为一个 Bean
    @Bean
    public RetryFilterConfig retryFilterConfig() {
        return new RetryFilterConfig();
    }
}