Sentinel 服务熔断 OpenFeign

Feign组件一般是消费侧

1.POM中增加openfeign引入

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <parent>
        <artifactId>springcloud-nacos</artifactId>
        <groupId>com.ckfuture.springcloud</groupId>
        <version>1.0-SNAPSHOT</version>
    </parent>
    <modelVersion>4.0.0</modelVersion>

    <artifactId>cloudalibaba-consumer-nacos-order84</artifactId>

    <dependencies>
        <!--SpringCloud alibaba nacos-->
        <dependency>
            <groupId>com.alibaba.cloud</groupId>
            <artifactId>spring-cloud-starter-alibaba-nacos-discovery</artifactId>
        </dependency>
        <!--SpringCloud alibaba sentinel-->
        <dependency>
            <groupId>com.alibaba.cloud</groupId>
            <artifactId>spring-cloud-starter-alibaba-sentinel</artifactId>
        </dependency>
        <!--SpringCloud openfeign-->
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-openfeign</artifactId>
        </dependency>
        <!--web+actuator-->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-actuator</artifactId>
        </dependency>
    </dependencies>

</project>

2.YML中激活Sentinel对Feign的支持

server:
  port: 84
spring:
  application:
    name: nacos-order-consumer
  cloud:
    nacos:
      discovery:
        server-addr: localhost:8848
    sentinel:
      transport:
        #配置Sentinel dashboard地址
        dashboard: localhost:8080
        port: 8719

#消费者将要去访问的微服务名称（注册成功进nacos的微服务提供者）
service-url:
  nacos-user-service: http://nacos-payment-provider
#激活Sentinel 对Feign的支持
feign:
  sentinel:
    enabled: true

3.主启动类激活@EnableFeignClients

package com.ckfuture.springcloud;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.client.discovery.EnableDiscoveryClient;
import org.springframework.cloud.openfeign.EnableFeignClients;

@SpringBootApplication
@EnableDiscoveryClient
@EnableFeignClients
public class OrderNacosMain84 {
    public static void main(String[] args) {
        SpringApplication.run(OrderNacosMain84.class,args);
    }
}

 4.新建带@FeignClient注解的业务接口

Feign就是接口+注解

接口中方法调用地址要和生产者中的调用地址一样。参考Feign调用方式

package com.ckfuture.springcloud.service;

import org.springframework.cloud.openfeign.FeignClient;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PathVariable;

/**
 * @author ckfuture
 */
@FeignClient(value = "nacos-payment-provider")
public interface PaymentService {

    @GetMapping(value = "/payment/nacos/{id}")
    public String getPayment(@PathVariable("id") Integer id);

}

 5.创建Feign兜底类

创建名为“PaymentFallbackService”的类，实现PaymentService接口方法

package com.ckfuture.springcloud.service;

import org.springframework.stereotype.Component;

/**
 * Feign
 * 兜底类
 */
@Component
public class PaymentFallbackService implements PaymentService{
    @Override
    public String getPayment(Integer id) {
        return "服务降级返回，---PaymentFallbackService";
    }
}

6.接口中添加fallback（兜底）方法

package com.ckfuture.springcloud.service;

import org.springframework.cloud.openfeign.FeignClient;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PathVariable;

/**
 * @author ckfuture
 */
@FeignClient(value = "nacos-payment-provider",fallback = PaymentFallbackService.class)
public interface PaymentService {

    @GetMapping(value = "/payment/nacos/{id}")
    public String getPayment(@PathVariable("id") Integer id);
}

7.添加controller方法

//=============OpenFeign============
    @Resource
    private PaymentService paymentService;

    @GetMapping(value = "/consumer/payment/nacos/{id}")
    public String getPayment(@PathVariable("id") Integer id){
        return paymentService.getPayment(id);
    }

8.测试

启动9001生产者微服务，在Nacos中查看。

 启动84端口的消费者，在Nacos中查看

 此时故意关闭9001端口微服务，再次请求查看效果。