基于Spring 6.1 RestClient构建高可用声明式HTTP客户端方案详解

<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-web</artifactId>
</dependency>
<dependency>
    <groupId>org.springframework.cloud</groupId>
    <artifactId>spring-cloud-starter-loadbalancer</artifactId>
</dependency>
<dependency>
    <groupId>org.springframework</groupId>
    <artifactId>spring-web</artifactId>
    <version>6.1.0+</version> <!-- 必须6.1+ -->
</dependency>

/**  
 * <pre>
 *  调用远程同步角色权限服务
 *    注：http://horus/horus这个配置，非常关键：
 *       1. 第一个horus表示远程服务应用的名字（注册到nacos注册中心的应用名，运行期间会被负载均衡拦截并替换成实际的ip和端口）
 *       2. 第二个horus配置表示远程服务的base上下文路径，即contextPath，如果远程应用不带上下文路径，这里配置成http://horus即可
 * </pre>
 * @author sinhy
 * @since 2022-07-13 17:00
 * @version V1.0  
 */
@HttpExchange(url = "http://horus/horus")
public interface AuthoritySyncSDKService
{
    /**
     * 同步角色权限
     * @author sinhy
     * @since 2022-07-13 16:06  void
     */
    @PostExchange("/syncRoleAuthority")
    void syncRoleAuthority();
}

@Configuration
public class HttpExchangeFluxConfiguration
{
    /**
     *  @LoadBalanced负载均衡注入，此注解用于标记RestTemplate、RestClient或WebClient.Builder这几类对象。将生成器bean配置为使用LoadBalancerClient。
     * @author lilinhai
     * @since 2025-04-15 16:23 
     * @return WebClient.Builder
     */
    @LoadBalanced
    @Bean
    public RestClient.Builder loadBalancedWebClientBuilder()
    {
        return RestClient.builder().requestFactory(new HttpComponentsClientHttpRequestFactory(httpClient()));
    }
    @Bean
    public TokenPropagationExchangeFilterFunction tokenFilter()
    {
        return new TokenPropagationExchangeFilterFunction();
    }
    @Bean
    public HttpServiceProxyFactory httpServiceProxyFactory(RestClient.Builder restClientBuilder, TokenPropagationExchangeFilterFunction tokenFilter)
    {
        restClientBuilder.requestInterceptor(tokenFilter);
        RestClient restClient = restClientBuilder.build();
        return HttpServiceProxyFactory.builderFor(RestClientAdapter.create(restClient)).build();
    }
    private PoolingHttpClientConnectionManager poolingConnManager()
    {
        PoolingHttpClientConnectionManager pool = new PoolingHttpClientConnectionManager();
        // 最大连接数
        pool.setMaxTotal(200);
        // 每个路由的最大连接数
        pool.setDefaultMaxPerRoute(50);
        return pool;
    }
    private HttpClient httpClient()
    {
        return HttpClients.custom()
            .setConnectionManager(poolingConnManager())
            .setConnectionReuseStrategy(new DefaultClientConnectionReuseStrategy())
            .evictExpiredConnections()
            .evictIdleConnections(TimeValue.ofSeconds(30))
            .build();
    }
}

/**  
 * 令牌透传过滤器
 * @author lilinhai
 * @since 2025-04-15 14:35
 * @version V1.0  
 */
public class TokenPropagationExchangeFilterFunction implements ClientHttpRequestInterceptor
{
    @Override
    public ClientHttpResponse intercept(HttpRequest request, byte[] body, ClientHttpRequestExecution execution) throws IOException
    {
        // 设置授权信息
        RequestAttributes ra = RequestContextHolder.getRequestAttributes();
        if (ra != null)
        {
            ServletRequestAttributes servletRequestAttributes = (ServletRequestAttributes) ra;
            String clientInfoJsonStr = servletRequestAttributes.getRequest().getHeader(WebHttpConstant.CLIENT_INFO_HEADER_NAME);
            if (clientInfoJsonStr != null)
            {
                request.getHeaders().add(WebHttpConstant.CLIENT_INFO_HEADER_NAME, clientInfoJsonStr);
            }
            String acceptLanguage = servletRequestAttributes.getRequest().getHeader(HttpHeaders.ACCEPT_LANGUAGE);
            if (acceptLanguage != null)
            {
                request.getHeaders().add(HttpHeaders.ACCEPT_LANGUAGE, acceptLanguage);
            }
        }
        return execution.execute(request, body);
    }
}

@RestController
@RequestMapping("/authority")
public class AuthoritySyncController {
    private final AuthoritySyncSDKService authoritySyncSDKService;
    public AuthoritySyncController(AuthoritySyncSDKService authoritySyncSDKService)
    {
        this.authoritySyncSDKService = authoritySyncSDKService;
    }
    @GetMapping("/sync")
    public void sync() {
        authoritySyncSDKService.syncRoleAuthority();
    }
}