【SpringCloud】（十二）：Fegion的Hystrix支持

  Fegion也支持Hystrix。当服务提供者出现异常的时候，使用Hystrix回调方法。

  在前面文章中提到的microservice-comsumer-movie-feign的基础上进行修改，主要是有一个回调的方法。

启动类：

package com.dynamic.cloud;import org.springframework.boot.SpringApplication;import org.springframework.boot.autoconfigure.SpringBootApplication;import org.springframework.cloud.netflix.eureka.EnableEurekaClient;import org.springframework.cloud.netflix.feign.EnableFeignClients;@SpringBootApplication@EnableEurekaClient@EnableFeignClientspublic class ComsumerMovieFeignApplication {public static void main(String[] args) {SpringApplication.run(ComsumerMovieFeignApplication.class, args);}}

Controller

package com.dynamic.cloud.controller;import org.springframework.beans.factory.annotation.Autowired;import org.springframework.web.bind.annotation.GetMapping;import org.springframework.web.bind.annotation.PathVariable;import org.springframework.web.bind.annotation.RestController;import com.dynamic.cloud.entity.User;import com.dynamic.cloud.feign.UserFeignClient;@RestControllerpublic class MovieController {@Autowiredprivate UserFeignClient userFeignClient;@GetMapping("/movie/{id}")public User findById(@PathVariable Long id){return this.userFeignClient.findById(id);}}

UserFeignClient 

package com.dynamic.cloud.feign;import org.springframework.cloud.netflix.feign.FeignClient;import org.springframework.web.bind.annotation.PathVariable;import org.springframework.web.bind.annotation.RequestMapping;import org.springframework.web.bind.annotation.RequestMethod;import com.dynamic.cloud.entity.User;@FeignClient(name="microservice-provider-user",fallback =HystrixClientFallback.class)public interface UserFeignClient {@RequestMapping(value="/simple/{id}",method = RequestMethod.GET) //只能是RequestMappingpublic User findById(@PathVariable("id") Long id); //@PathVariable需要设置括号中的名称}

@FeignClient，要用name 和 fallback 

HystrixClientFallback要实现UserFeignClient，并且加入到容器中。

package com.dynamic.cloud.feign;import org.springframework.stereotype.Component;import com.dynamic.cloud.entity.User;@Componentpublic class HystrixClientFallback implements UserFeignClient {@Overridepublic User findById(Long id) {User user = new User();user.setId(0L);return user;}}

  启动Eureka，用户微服务和修改后的电影微服务。正常情况下，电影微服务调用用户微服务显示数据，当用户微服务出现异常时。电影微服务执行回调方法。