feign + hystrix 降级

Posted 2021-04-30 程序餐厅

feign 启用 hystrix

feign 默认没有启用 hystrix，添加配置，启用 hystrix

• feign.hystrix.enabled=true

application.yml 添加配置

feign: hystrix:    enabled: true

启用 hystrix 后，访问服务
http://localhost:3001/item-service/35

默认1秒会快速失败，没有降级方法时，会显示白板页

可以添加配置，暂时减小降级超时时间，以便后续对降级进行测试

......
feign: hystrix: enabled: true hystrix: command: default: execution: isolation: thread: timeoutInMilliseconds: 500

feign + hystrix 降级

feign 远程接口中指定降级类

远程调用失败, 会执行降级类中的代码

ItemFeignService

...@FeignClient(name="item-service", fallback = ItemFeignServiceFB.class)public interface ItemFeignService {...

UserFeignService

...@FeignClient(name="user-service", fallback = UserFeignServiceFB.class)public interface UserFeignService {...

OrderFeignService

...@FeignClient(name="order-service",fallback = OrderFeignServiceFB.class)public interface OrderFeignService {...

降级类

降级类需要实现远程接口

ItemFeignServiceFB

package cn.tedu.sp09.service;
import java.util.List;import org.springframework.stereotype.Component;import cn.tedu.sp01.pojo.Item;import cn.tedu.web.util.JsonResult;
@Componentpublic class ItemFeignServiceFB implements ItemFeignService {
 @Override public JsonResult<List<Item>> getItems(String orderId) { return JsonResult.err("无法获取订单商品列表"); }
 @Override public JsonResult decreaseNumber(List<Item> items) { return JsonResult.err("无法修改商品库存"); }
}

UserFeignServiceFB

package cn.tedu.sp09.service;
import org.springframework.stereotype.Component;import cn.tedu.sp01.pojo.User;import cn.tedu.web.util.JsonResult;
@Componentpublic class UserFeignServiceFB implements UserFeignService {
 @Override public JsonResult<User> getUser(Integer userId) { return JsonResult.err("无法获取用户信息"); }
 @Override public JsonResult addScore(Integer userId, Integer score) { return JsonResult.err("无法增加用户积分"); }
}

OrderFeignServiceFB

package cn.tedu.sp09.service;
import org.springframework.stereotype.Component;import cn.tedu.sp01.pojo.Order;import cn.tedu.web.util.JsonResult;
@Componentpublic class OrderFeignServiceFB implements OrderFeignService {
 @Override public JsonResult<Order> getOrder(String orderId) { return JsonResult.err("无法获取商品订单"); }
 @Override public JsonResult addOrder() { return JsonResult.err("无法保存订单"); }
}

启动服务，访问测试

http://localhost:3001/item-service/35