问题描述：

现有三个工程 A,B,C。  A工程会访问B工程接口，也会访问C工程接口，原来的做法是写好两个接口类去访问，如下所示，但是访问时出现问题，当第一次访问时，A调用B成功，A调用C成功。但第二次访问时，A调用B时，报错404

@FeignClient
public interface A{/*** * @Title getConfigsOfService* @Description 获取服务的配置* @param name* @return* @return String*/@GetMapping(value = "/data_control_web/ambari/service/getConfigsOfService")public String getConfigsOfService(@RequestParam("serviceName") String serviceName,@RequestParam("engineeringId") int engineeringId);}

@FeignClient
public interface B{/*** * @Title detailFileResourceVersion* @Description 获取文件详情* @param fileResourceId* @param version* @param engineeringId* @return* @return String*/@GetMapping("/data_resource_manage/resource/file/version/detail")public String detailFileResourceVersion(@RequestParam("fileResourceId") int fileResourceId,@RequestParam("version") String version,@RequestParam("engineeringId") int engineeringId);
}

解决方法：

A，B接口去掉@FeignClient注解，再编写一个类RemoteXxxClient，通过反射方式注解两个接口，如下图所示

import com.alibaba.fastjson.support.spring.FastJsonHttpMessageConverter;
import com.netflix.appinfo.InstanceInfo;
import com.netflix.discovery.EurekaClient;import feign.Contract;
import feign.Feign;
import feign.Request;
import feign.codec.Decoder;
import feign.codec.Encoder;
import org.springframework.beans.factory.ObjectFactory;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.autoconfigure.http.HttpMessageConverters;
import org.springframework.cloud.openfeign.FeignClient;
import org.springframework.cloud.openfeign.FeignContext;
import org.springframework.cloud.openfeign.support.SpringDecoder;
import org.springframework.cloud.openfeign.support.SpringEncoder;
import org.springframework.http.MediaType;
import org.springframework.context.annotation.Bean;
import org.springframework.stereotype.Component;import java.util.ArrayList;
import java.util.List;
import java.util.Map;
import java.util.Objects;
import java.util.concurrent.ConcurrentHashMap;/*** Feign配置类，负责实例化所需要的伪客户端*/
@Component
public class RemoteXxxClient {public final static String DATA_RESOURCE_MANAGER = "DATA-RESOURCE-MANAGER";public final static String DATA_CONTROL_WEB = "DATA-CONTROL-WEB";/*** FeignClientFactoryBean 该工厂类中 设置builder属性时就是通过该对象，源码中可看到*/protected FeignContext feignContext;/*** 通过注入Eureka实例对象，就不用手动指定url，只需要指定服务名即可*/protected EurekaClient eurekaClient;private static final Map<String, Object> FEIGN_CLIENTS = new ConcurrentHashMap<>();@Autowiredpublic void init(final EurekaClient eurekaClient, final FeignContext feignContext) {this.eurekaClient = eurekaClient;this.feignContext = feignContext;}@Beanpublic A getQcloudService() {return create(A.class, DATA_CONTROL_WEB);}@Beanpublic B getTaskService() {return create(B.class, DATA_RESOURCE_MANAGER);}/*** 设置编码解码器为FastJson** @param clazz* @param serverId* @param <T>* @return*/protected <T> T create(Class<T> clazz, String serverId) {InstanceInfo nextServerFromEureka = eurekaClient.getNextServerFromEureka(serverId, false);String key = nextServerFromEureka.getIPAddr() + ":" + nextServerFromEureka.getPort() + ":"+ clazz.getName();Object object = FEIGN_CLIENTS.get(key);if (Objects.isNull(object)) {object = Feign.builder()// encoder指定对象编码方式.encoder(this.feignEncoder())// decoder指定对象解码方式.decoder(this.feignDecoder())// .client(feignClient)// options方法指定连接超时时长及响应超时时长.options(new Request.Options(5000, 5000))// retryer方法指定重试策略// .retryer(new Retryer.Default(5000, 5000, 3)).contract(feignContext.getInstance(serverId, Contract.class))// 自己写的类，传输token，不需要的话可以去掉.requestInterceptor(new TokenConfig())// target方法绑定接口与服务端地址。返回类型为绑定的接口类型。.target(clazz, nextServerFromEureka.getHomePageUrl());FEIGN_CLIENTS.put(key, object);}return (T) object;}protected Encoder feignEncoder() {return new SpringEncoder(feignHttpMessageConverter());}protected Decoder feignDecoder() {return new SpringDecoder(feignHttpMessageConverter());}/*** 设置解码器为fastjson** @return*/private ObjectFactory<HttpMessageConverters> feignHttpMessageConverter() {final HttpMessageConverters httpMessageConverters =new HttpMessageConverters(this.getFastJsonConverter());return () -> httpMessageConverters;}private FastJsonHttpMessageConverter getFastJsonConverter() {FastJsonHttpMessageConverter converter = new FastJsonHttpMessageConverter();List<MediaType> supportedMediaTypes = new ArrayList<>();MediaType mediaTypeJson = MediaType.valueOf(MediaType.APPLICATION_JSON_UTF8_VALUE);supportedMediaTypes.add(mediaTypeJson);converter.setSupportedMediaTypes(supportedMediaTypes);return converter;}
}

访问方式：

类中直接引用接口即可

@@Autowired
private  A a;@@Autowired
private  B b;