Spring Cloud Alibaba-Feign整合Sentinel

第1步: 引入sentinel的依赖

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

第2步: 在配置文件中开启Feign对Sentinel的支持

feign:
sentinel:enabled: true

第3步: 创建容错类

//容错类要求必须实现被容错的接口,并为每个方法实现容错方案
@Component
@Slf4j
public class ProductServiceFallBack implements ProductService {@Overridepublic Product findByPid(Integer pid) {Product product = new Product();product.setPid(-1);return product;}
}

第4步: 为被容器的接口指定容错类

//value用于指定调用nacos下哪个微服务
//fallback用于指定容错类
@FeignClient(value = "service-product", fallback = ProductServiceFallBack.class)
public interface ProductService {@RequestMapping("/product/{pid}")//指定请求的URI部分Product findByPid(@PathVariable Integer pid);
}

第5步: 修改controller

@RestController
@Slf4j
public class OrderController {@Autowiredprivate OrderService orderService;@Autowiredprivate ProductService productService;//下单--fegin@RequestMapping("/order/prod/{pid}")public Order order(@PathVariable("pid") Integer pid) {log.info("接收到{}号商品的下单请求,接下来调用商品微服务查询此商品信息", pid);//调用商品微服务,查询商品信息Product product = productService.findByPid(pid);if (product.getPid() == -1) {Order order = new Order();order.setPname("下单失败");return order;}log.info("查询到{}号商品的信息,内容是:{}", pid, JSON.toJSONString(product));//下单(创建订单)Order order = new Order();order.setUid(1);order.setUsername("测试用户");order.setPid(pid);order.setPname(product.getPname());order.setPprice(product.getPprice());order.setNumber(1);orderService.createOrder(order);log.info("创建订单成功,订单信息为{}", JSON.toJSONString(order));try {Thread.sleep(100);} catch (InterruptedException e) {e.printStackTrace();}return order;}
}

第6步: 停止所有 shop-product 服务,重启 shop-order 服务,访问请求,观察容错效果

扩展: 如果想在容错类中拿到具体的错误,可以使用下面的方式

@FeignClient(value = "service-product",//fallback = ProductServiceFallBack.class,fallbackFactory = ProductServiceFallBackFactory.class)
public interface ProductService {//@FeignClient的value + @RequestMapping的value值 其实就是完成的请求地址
"http://service-product/product/" + pid@RequestMapping("/product/{pid}")//指定请求的URI部分Product findByPid(@PathVariable Integer pid);
}
@Component
public class ProductServiceFallBackFactory implements
FallbackFactory<ProductService> {@Overridepublic ProductService create(Throwable throwable) {return new ProductService() {@Overridepublic Product findByPid(Integer pid) {throwable.printStackTrace();Product product = new Product();product.setPid(-1);return product;}};}
}