sentinel实现对openfeign保护

1. 引入依赖

   <dependency>
       <groupId>com.alibaba.cloud</groupId>
       <artifactId>spring-cloud-starter-alibaba-sentinel</artifactId>
   </dependency>

2. yml添加配置

   feign:
     sentinel:
       enabled: true

3. 编写feign接口并配置fallback属性

   @FeignClient(value = "nacos-client-app"
           , contextId = "nacosHelloClient"
           , fallback = NacosHelloClientFallback.class
   )
   public interface NacosHelloClient {
   
       @GetMapping("/hello/index")
       String hello() ;
   
       @GetMapping("/hello/exception")
       String exception() ;
   }

4. 编写fallback实现代码

   @Component
   public class NacosHelloClientFallback implements NacosHelloClient {
   
       @Override
       public String hello() {
           return "fallback hello ret value";
       }
       @Override
       public String exception() {
           return "fallback exception ret value";
       }
   }