SpringCloud Fegin默认已为Feign整合了hystrix，所以添加Feign依赖后就不用在添加hystrix，那么怎么才能让Feign的熔断机制生效呢，只要按以下步骤开发：
一，添加feign依赖
<!--springCloud整合feign-->
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-openfeign</artifactId>
</dependency>二，配置application.yml 在Feign中开启hystrix
在Feign中已经内置了hystrix，但是默认是关闭的需要在工程的application.yml中开启对hystrix的支持
server:
port: 9013
tomcat:
max-threads: 10 # 设置线程数为最大10个
spring:
application:
name: service-order-hystrix
datasource:
driver-class-name: com.mysql.jdbc.Driver
url: jdbc:mysql://localhost:3306/springclouddemo?useUnicode=true&characterEncoding=utf8&serverTimezone=UTC
username: root
password: root
jpa:
database: MySQL
show-sql: true
open-in-view: true
eureka:
client:
service-url:
defaultZone: http://localhost:9003/eureka/,http://localhost:9004/eureka/
instance:
prefer-ip-address: true
instance-id: ${spring.cloud.client.ip-address}:${server.port} #向注册中心中展示注册服务id
lease-expiration-duration-in-seconds: 10 #eureka client 发送心跳给server端后，续约到期时间（默认为90秒）。
lease-renewal-interval-in-seconds: 5 # 发送心跳续约间隔（每一个心跳的间隔）
#修改ribbon的负载均衡策略 服务名-ribbon-NFLoadBalancer
service-product:
ribbon:
NFLoadBalancerRuleClassName: com.netflix.loadbalancer.RandomRule
ConnectTimeout: 250 # Ribbon的连接超时时间
ReadTimeout: 3000 # Ribbon的数据读取超时时间
OkToRetryOnAllOperations: true # 是否对所有操作都进行重试
MaxAutoRetriesNextServer: 1 # 切换实例的重试次数
MaxAutoRetries: 1 # 对当前实例的重试次数
feign:
client:
config:
service-product: # 服务提供者的服务名称
loggerLevel: FULL
hystrix:
enabled: true
logging:
level:
com.zjk.order.feign.productFeignHttpClient: debug #feign的自定义接口三，修改productFeignClient添加hystrix熔断
//指定需要调用的服务名称
@FeignClient(name = "service-product",fallback = ProductFeignClientCallBack.class)
public interface productFeignHttpClient {
//调用的请求路径
@RequestMapping(value = "/product/{Id}",method = RequestMethod.GET)
public TbProduct findById(@PathVariable("Id") Long Id);
}四，配置FeignClient接口的实现类
@Component
public class ProductFeignClientCallBack implements productFeignHttpClient {
@Override
public TbProduct findById(Long Id) {
TbProduct tbProduct = new TbProduct();
tbProduct.setProductName("服务降级");
return tbProduct;
}
}@FeignClient注解中以fallback声明降级方法