Feign使用Hystrix（断路器的使用）

前言

在springcloud中，为Feign添加回退更加简单。事实上，springcloud默认已为Feign整合了Hystrix，要想为Feign打开Hystrix支持，只需要设置feign.hystrix.enabled=true即可。

编码

1.复制项目microservie-consumer-movie-feign,将ArtifactId修改为microservice-consumer-movie-feign-hystrix-fallback.

2.在application.yml中添加feign.hystrix.enabled: true,从而开启Feign的Hystrix支持。

server:
  port: 8082
eureka:
  client:
    serviceUrl:
      defaultZone: http://localhost:8083/eureka/
  instance:
    prefer-ip-address: true
spring:
  application:
    name: microservice-consumer-movie
feign:
  hystrix:
    enabled: true

 

3.将之前编写的Feign接口修改成如下内容：

@FeignClient(name = "microservice-provider-user",fallback = FeignClientFallback.class)
public interface UserFeignClient {
    @RequestMapping(value="/{id}",method = RequestMethod.GET)
    public User findById(@PathVariable("id") Long id);
}
@Component
class FeignClientFallback implements UserFeignClient{
    public User findById(Long id) {
        User user = new User();
        user.setId(-1L);
        user.setUsername("默认用户");
        return user;
    }
}

由代码可知，只需使用@FeignClient注解的fallback属性，就可为指定名称的Feign客户添加回退。

测试

启动microservice-discovery-eureka.

启动microservice-provider-user.

启动microservice-consumer-movie-feign-hystrix-fallback.

访问http://localhost:8082/user/1,可正常获得结果。

{"id":1,"username":"account1","name":"张三","age":20,"balance":98.23}

停止microservice-provider-user.

再次访问http://localhost:8082/user/1,可获得如下结果。说明当用户微服务不可用时，进入了回退的逻辑。

{"id":-1,"username":"默认用户","name":null,"age":null,"balance":null}

补充：在springcloud Dalston之前的版本中，Feign默认开启Hystrix支持，无需设置feign.hystrix.enabled=true.从springcloud Dalston版本开始，Feign的Hystrix支持默认关闭，需要手动设置开启。

由于代码过于简单，这里就不提交源码了

标签：feign,Hystrix,Feign,断路器,user,microservice,id
来源： https://blog.csdn.net/Dingwensheng1222/article/details/97282896