@FeignClient同一个name使用多个配置类(详细教程)

@FeignClient无法支持同一service具有多种不同配置的FeignClient，因此，在必要时需要手动build FeignClient

首先创建FeignClientConfigurer类，这个类相当于build FeignClient的工具类

FeignClientConfigurer.java

@Import(FeignClientsConfiguration.class)
public class FeignClientConfigurer {

    private Decoder decoder;
    private Encoder encoder;
    private Client client;
    private Contract contract;
    private LoadBalancedResourceDetails loadBalancedResourceDetails;

    public FeignClientConfigurer(Decoder decoder, Encoder encoder, Client client, Contract contract, LoadBalancedResourceDetails loadBalancedResourceDetails) {
        this.decoder = decoder;
        this.encoder = encoder;
        this.client = client;
        this.contract = contract;
        this.loadBalancedResourceDetails = loadBalancedResourceDetails;
    }

    public RequestInterceptor getOAuth2RequestInterceptor() {
        return new OAuth2FeignRequestInterceptor(new DefaultOAuth2ClientContext(), loadBalancedResourceDetails);
    }


    public RequestInterceptor getUserFeignClientInterceptor() {
        return new UserFeignClientInterceptor();
    }


    public  T buildAuthorizedFeignClient(Class clazz, String serviceName) {
        return getBasicBuilder().requestInterceptor(getOAuth2RequestInterceptor()).target(clazz, buildServiceUrl(serviceName));
    }

    public  T buildAuthorizedUserFeignClient(Class clazz, String serviceName) {
        return getBasicBuilder().requestInterceptor(getUserFeignClientInterceptor()).target(clazz, buildServiceUrl(serviceName));
    }

    private String buildServiceUrl(String serviceName) {
        return "http://" + serviceName;
    }

    protected Feign.Builder getBasicBuilder() {
        return Feign.builder().client(client).encoder(encoder).decoder(decoder).contract(contract);
    }
}

使用工具类的方法创建多个FeignClient配置

FeignClientConfiguration.java

@Configuration
public class FeignClientConfiguration extends FeignClientConfigurer {
    public FeignClientConfiguration(Decoder decoder, Encoder encoder, Client client, Contract contract, LoadBalancedResourceDetails loadBalancedResourceDetails) {
        super(decoder, encoder, client, contract, loadBalancedResourceDetails);
    }

    @Bean
    public UaaFeignClient uaaFeignClient() {
        return super.buildAuthorizedFeignClient(UaaFeignClient.class, "uaa");
    }

    @Bean
    public QueryUserFeignClient queryUserFeignClient() {
        return super.buildAuthorizedUserFeignClient(QueryUserFeignClient.class, "uaa");
    }
}

其中，super.buildAuthorizedUserFeignClient()方法中，第一个参数为调用别的服务的接口类，第二个参数为被调用服务在注册中心的service-id。

UaaFeignClient.java

public interface UaaFeignClient {

    @RequestMapping(value = "/users", method = RequestMethod.GET)
    UserDTO getUser(@RequestParam("userId") String userId);
    
}