@FeignClient("xxxClient")
public interface xxxClient{
}

@Configuration
public class FeignClientsConfiguration {
	@Autowired
	private ObjectFactory<HttpMessageConverters> messageConverters;
	@Autowired(required = false)
	private List<AnnotatedParameterProcessor> parameterProcessors = new ArrayList<>();
	@Autowired(required = false)
	private List<FeignFormatterRegistrar> feignFormatterRegistrars = new ArrayList<>();
	@Autowired(required = false)
	private Logger logger;
	@Bean
	@ConditionalOnMissingBean
	public Decoder feignDecoder() {
		return new OptionalDecoder(new ResponseEntityDecoder(new SpringDecoder(this.messageConverters)));
	}
	@Bean
	@ConditionalOnMissingBean
	public Encoder feignEncoder() {
		return new SpringEncoder(this.messageConverters);
	}
	@Bean
	@ConditionalOnMissingBean
	public Contract feignContract(ConversionService feignConversionService) {
		return new SpringMvcContract(this.parameterProcessors, feignConversionService);
	}
	@Bean
	public FormattingConversionService feignConversionService() {
		FormattingConversionService conversionService = new DefaultFormattingConversionService();
		for (FeignFormatterRegistrar feignFormatterRegistrar : feignFormatterRegistrars) {
			feignFormatterRegistrar.registerFormatters(conversionService);
		}
		return conversionService;
	}

	@Configuration
	@ConditionalOnClass({ HystrixCommand.class, HystrixFeign.class })
	protected static class HystrixFeignConfiguration {
		@Bean
		@Scope("prototype")
		@ConditionalOnMissingBean
		@ConditionalOnProperty(name = "feign.hystrix.enabled")
		public Feign.Builder feignHystrixBuilder() {
			return HystrixFeign.builder();
		}
	}
	@Bean
	@ConditionalOnMissingBean
	public Retryer feignRetryer() {
		return Retryer.NEVER_RETRY;
	}
	@Bean
	@Scope("prototype")
	@ConditionalOnMissingBean
	public Feign.Builder feignBuilder(Retryer retryer) {
		return Feign.builder().retryer(retryer);
	}
	@Bean
	@ConditionalOnMissingBean(FeignLoggerFactory.class)
	public FeignLoggerFactory feignLoggerFactory() {
		return new DefaultFeignLoggerFactory(logger);
	}
}

protected Feign.Builder feign(FeignContext context) {
		FeignLoggerFactory loggerFactory = get(context, FeignLoggerFactory.class);
		Logger logger = loggerFactory.create(type);

		// @formatter:off 從spring上下文中獲取對應的Bean
		Feign.Builder builder = get(context, Feign.Builder.class)
				// required values
				.logger(logger)
				.encoder(get(context, Encoder.class))
				.decoder(get(context, Decoder.class))
				.contract(get(context, Contract.class));
		// @formatter:on

		configureFeign(context, builder);

		return builder;
	}

@Configuration
public class FeignClientsConfiguration {

    @Bean
    public Decoder feignDecoder() {
        return new ResultDecoder();
    }

    @Bean
    public Encoder feignEncoder() {
        return new ParamEncoder();
    }

    @Bean
    public Contract feignContract() {
        return new DefaultContract();
    }
}

/**
	 * A custom <code>@Configuration</code> for the feign client. Can contain override
	 * <code>@Bean</code> definition for the pieces that make up the client, for instance
	 * {@link feign.codec.Decoder}, {@link feign.codec.Encoder}, {@link feign.Contract}.
	 *
	 * @see FeignClientsConfiguration for the defaults
	 */
	Class<?>[] configuration() default {};

public class SelfFeignClientsConfiguration {
    @Bean
    @ConditionalOnMissingBean(name = "SelfFeignDecoder")
    public Decoder SelfFeignDecoder() {
        return new JacksonDecoder();
    }
}

@FeignClient(name = "xxxClient", configuration = SelfFeignClientsConfiguration.class)
public interface xxxClient{
}