跟我学Spring Cloud（Finchley版）-14-Feign使用Hystrix

Feign默认已经整合了Hystrix，本节详细探讨Feign使用Hystrix的具体细节。

服务降级

加配置，默认Feign是不启用Hystrix的，需要添加如下配置启用Hystrix，这样所有的Feign Client都会受到Hystrix保护！

1 2 3 feign: hystrix: enabled: true

提供Fallback：

1 2 3 4 5 6 7 8 9 10 11 12 13 @FeignClient(name = "microservice-provider-user", fallback = UserFeignClientFallback.class) public interface UserFeignClient { @GetMapping("/users/{id}") User findById(@PathVariable("id") Long id); } @Component class UserFeignClientFallback implements UserFeignClient { @Override public User findById(Long id) { return new User(id, "默认用户", "默认用户", 0, new BigDecimal(1)); } }

获得造成fallback的原因

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 @FeignClient(name = "microservice-provider-user", fallbackFactory = UserFeignClientFallbackFactory.class) public interface UserFeignClient { @GetMapping("/users/{id}") User findById(@PathVariable("id") Long id); } @Component @Slf4j class UserFeignClientFallbackFactory implements FallbackFactory<UserFeignClient> { @Override public UserFeignClient create(Throwable throwable) { return new UserFeignClient() { @Override public User findById(Long id) { log.error("进入回退逻辑", throwable); return new User(id, "默认用户", "默认用户", 0, new BigDecimal(1)); } }; } }

Feign启用/禁用Hystrix

全局启用

1 feign.hystrix.enabled: true

全局禁用

1 feign.hystrix.enabled: false

或直接省略不写。

局部启用

利用Feign配置的自定义，为指定Feign Client指定如下配置类即可，Feign配置自定义详见：跟我学Spring Cloud（Finchley版）-10-Feign深入

1 2 3 4 5 6 7 public class FeignDisableHystrixConfiguration { @Bean @Scope("prototype") public HystrixFeign.Builder feignBuilder() { return HystrixFeign.builder(); } }

局部禁用

1 2 3 4 5 6 7 public class FeignDisableHystrixConfiguration { @Bean @Scope("prototype") public Feign.Builder feignBuilder() { return Feign.builder(); } }

配套代码

服务降级：

GitHub：https://github.com/eacdy/spring-cloud-study/tree/master/2018-Finchley/microservice-consumer-movie-feign-hystrixGitee：https://gitee.com/itmuch/spring-cloud-study/tree/master/2018-Finchley/microservice-consumer-movie-feign-hystrix

获得造成fallback的原因：

GitHub：https://github.com/eacdy/spring-cloud-study/tree/master/2018-Finchley/microservice-consumer-movie-feign-hystrix-fallback-factoryGitee：https://gitee.com/itmuch/spring-cloud-study/tree/master/2018-Finchley/microservice-consumer-movie-feign-hystrix-fallback-factory