[023-01-40].第40节：组件应用 - OpenFeign与 Sentinel 集成实现fallback服务降级

1.01^10002025-03-13 17:13

SpringCloud学习大纲

一、需求说明：

需求1：通过fallback属性进行统一配置

a.问题分析：

  • 1.需要实现cloudalibaba-consumer-nacos-order83模块通过OpenFeign调用cloudalibaba-provider-payment9001
    • 83服务通过OpenFeign调用 9001微服务，正常访问OK
    • 83服务通过OpenFeign调用 9001微服务，异常访问error
  • 2.访问者要有fallback服务降级的情况，不要持续访问9001加大微服务负担，但是通过feign接口调用的各个方法又自不同，如果每个不同方法都加一个fallback配对方法，会导致代码膨胀不好管理，工程埋雷...

b.解决办法：

  • 在feign接口里面定义的全部方法都走统一的服务降级 ，一个搞定即可

需求2：Sentinel访问触发了自定义的限流配置

  • 9001微服务自身还带着sentinel内部配置的流控规则，如果满足也会被触发
  • Sentinel访问触发了自定义的限流配置,在注解@SentinelResource里面配置的blockHandler方法

二、案例实现：

2.1.启动nacos和Sentinue

  • 启动nacos: startup.cmd -m standalone
  • 启动Sentine: java -jar sentinel-dashboard-1.8.6.jar

2.2.修改服务启动方法：cloudalibaba-provider-payment9001

改pom

xml 复制代码 
<?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">
    <modelVersion>4.0.0</modelVersion>
    <parent>
        <groupId>com.atguigu.cloud</groupId>
        <artifactId>mscloudV5</artifactId>
        <version>1.0-SNAPSHOT</version>
    </parent>

    <artifactId>cloudalibaba-provider-payment9001</artifactId>

    <properties>
        <maven.compiler.source>17</maven.compiler.source>
        <maven.compiler.target>17</maven.compiler.target>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
    </properties>



    <dependencies>
        <!--openfeign-->
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-openfeign</artifactId>
        </dependency>
        <!--alibaba-sentinel-->
        <dependency>
            <groupId>com.alibaba.cloud</groupId>
            <artifactId>spring-cloud-starter-alibaba-sentinel</artifactId>
        </dependency>
        <!--nacos-discovery-->
        <dependency>
            <groupId>com.alibaba.cloud</groupId>
            <artifactId>spring-cloud-starter-alibaba-nacos-discovery</artifactId>
        </dependency>
        <!-- 引入自己定义的api通用包 -->
        <dependency>
            <groupId>com.atguigu.cloud</groupId>
            <artifactId>cloud-api-commons</artifactId>
            <version>1.0-SNAPSHOT</version>
        </dependency>
        <!--SpringBoot通用依赖模块-->
        <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>
        <!--hutool-->
        <dependency>
            <groupId>cn.hutool</groupId>
            <artifactId>hutool-all</artifactId>
        </dependency>
        <!--lombok-->
        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <version>1.18.28</version>
            <scope>provided</scope>
        </dependency>
        <!--test-->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>

</project>

写yml

java 复制代码 
server:
  port: 9001

spring:
  application:
    name: nacos-payment-provider
  cloud:
    nacos:
      discovery:
        server-addr: localhost:8848 #配置Nacos地址
    sentinel:
      transport:
        dashboard: localhost:8080 #配置Sentinel dashboard控制台服务地址
        port: 8719 #默认8719端口，假如被占用会自动从8719开始依次+1扫描,直至找到未被占用的端口

主启动：

java 复制代码 
package com.atguigu.cloud;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.boot.autoconfigure.jdbc.DataSourceAutoConfiguration;
import org.springframework.boot.autoconfigure.jdbc.DataSourceTransactionManagerAutoConfiguration;
import org.springframework.cloud.client.discovery.EnableDiscoveryClient;
@SpringBootApplication
@EnableDiscoveryClient
public class Main9001{
    public static void main(String[] args){
        SpringApplication.run(Main9001.class,args);
    }
}

业务类：

java 复制代码 
package com.atguigu.cloud.controller;

import cn.hutool.core.util.IdUtil;
import com.alibaba.csp.sentinel.annotation.SentinelResource;
import com.alibaba.csp.sentinel.slots.block.BlockException;
import com.atguigu.cloud.entities.PayDTO;
import com.atguigu.cloud.resp.ResultData;
import com.atguigu.cloud.resp.ReturnCodeEnum;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RestController;

import java.math.BigDecimal;

@RestController
public class PayAlibabaController{
    @Value("${server.port}")
    private String serverPort;

    @GetMapping(value = "/pay/nacos/{id}")
    public String getPayInfo(@PathVariable("id") Integer id){
        return "nacos registry, serverPort: "+ serverPort+"\t id"+id;
    }

    @GetMapping("/pay/nacos/get/{orderNo}")
    @SentinelResource(value = "getPayByOrderNo",blockHandler = "handlerBlockHandler")
    public ResultData getPayByOrderNo(@PathVariable("orderNo") String orderNo){
        //模拟从数据库查询出数据并赋值给DTO
        PayDTO payDTO = new PayDTO();

        payDTO.setId(1024);
        payDTO.setOrderNo(orderNo);
        payDTO.setAmount(BigDecimal.valueOf(9.9));
        payDTO.setPayNo("pay:"+IdUtil.fastUUID());
        payDTO.setUserId(1);

        return ResultData.success("查询返回值："+payDTO);
    }

    public ResultData handlerBlockHandler(@PathVariable("orderNo") String orderNo,BlockException exception){
        return ResultData.fail(ReturnCodeEnum.RC500.getCode(),"getPayByOrderNo服务不可用，" +
                "触发sentinel流控配置规则"+"\t"+"o(╥﹏╥)o");
    }


    /*
    fallback服务降级方法纳入到Feign接口统一处理，全局一个
    public ResultData myFallBack(@PathVariable("orderNo") String orderNo,Throwable throwable)
    {
        return ResultData.fail(ReturnCodeEnum.RC500.getCode(),"异常情况："+throwable.getMessage());
    }
    */
}

启动9001微服务：

2.3.修改cloud-api-commons

改pom

java 复制代码 
<?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">
    <modelVersion>4.0.0</modelVersion>
    <parent>
        <groupId>com.atguigu.cloud</groupId>
        <artifactId>cloud2024</artifactId>
        <version>1.0-SNAPSHOT</version>
    </parent>

    <artifactId>cloud-api-commons</artifactId>

    <properties>
        <maven.compiler.source>17</maven.compiler.source>
        <maven.compiler.target>17</maven.compiler.target>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
    </properties>

    <dependencies>
        <!--openfeign-->
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-openfeign</artifactId>
        </dependency>
        <!--alibaba-sentinel-->
        <dependency>
            <groupId>com.alibaba.cloud</groupId>
            <artifactId>spring-cloud-starter-alibaba-sentinel</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>
        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <optional>true</optional>
        </dependency>
        <!--hutool-->
        <dependency>
            <groupId>cn.hutool</groupId>
            <artifactId>hutool-all</artifactId>
        </dependency>
    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>

</project>

新增PayFeignSentinelApi接口：

java 复制代码 
package com.atguigu.cloud.apis;
import com.atguigu.cloud.resp.ResultData;
import org.springframework.cloud.openfeign.FeignClient;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PathVariable;
@FeignClient(value = "nacos-payment-provider",fallback = PayFeignSentinelApiFallBack.class)
public interface PayFeignSentinelApi{
    @GetMapping("/pay/nacos/get/{orderNo}")
    public ResultData getPayByOrderNo(@PathVariable("orderNo") String orderNo);
}

为远程调用新建全局统一服务降级类：

java 复制代码 
package com.atguigu.cloud.apis;

import com.atguigu.cloud.resp.ResultData;
import com.atguigu.cloud.resp.ReturnCodeEnum;
import org.springframework.stereotype.Component;

@Component
public class PayFeignSentinelApiFallBack implements PayFeignSentinelApi{
    @Override
    public ResultData getPayByOrderNo(String orderNo){
        return ResultData.fail(ReturnCodeEnum.RC500.getCode(),"对方服务宕机或不可用，FallBack服务降级o(╥﹏╥)o");
    }
}

业务类：

xml 复制代码 
<!-- 引入自己定义的api通用包 -->
<dependency>
    <groupId>com.atguigu.cloud</groupId>
    <artifactId>cloud-api-commons</artifactId>
    <version>1.0-SNAPSHOT</version>
</dependency>

2.4.修改cloudalibaba-consumer-nacos-order83

改pom

xml 复制代码 
<?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">
    <modelVersion>4.0.0</modelVersion>
    <parent>
        <groupId>com.atguigu.cloud</groupId>
        <artifactId>mscloudV5</artifactId>
        <version>1.0-SNAPSHOT</version>
    </parent>

    <artifactId>cloudalibaba-consumer-nacos-order83</artifactId>

    <properties>
        <maven.compiler.source>17</maven.compiler.source>
        <maven.compiler.target>17</maven.compiler.target>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
    </properties>

    <dependencies>
        <!-- 引入自己定义的api通用包 -->
        <dependency>
            <groupId>com.atguigu.cloud</groupId>
            <artifactId>cloud-api-commons</artifactId>
            <version>1.0-SNAPSHOT</version>
        </dependency>
        <!--openfeign-->
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-openfeign</artifactId>
        </dependency>
        <!--alibaba-sentinel-->
        <dependency>
            <groupId>com.alibaba.cloud</groupId>
            <artifactId>spring-cloud-starter-alibaba-sentinel</artifactId>
        </dependency>
        <!--nacos-discovery-->
        <dependency>
            <groupId>com.alibaba.cloud</groupId>
            <artifactId>spring-cloud-starter-alibaba-nacos-discovery</artifactId>
        </dependency>
        <!--loadbalancer-->
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-loadbalancer</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>
        <!--lombok-->
        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <optional>true</optional>
        </dependency>
    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>
</project>

写yml

java 复制代码 
server:
  port: 83

spring:
  application:
    name: nacos-order-consumer
  cloud:
    nacos:
      discovery:
        server-addr: localhost:8848
#消费者将要去访问的微服务名称(nacos微服务提供者叫什么你写什么)
service-url:
  nacos-user-service: http://nacos-payment-provider

# 激活Sentinel对Feign的支持
feign:
  sentinel:
    enabled: true

主启动：

java 复制代码 
package com.atguigu.cloud;

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


@EnableDiscoveryClient
@SpringBootApplication
@EnableFeignClients
public class Main83{
    public static void main(String[] args){
        SpringApplication.run(Main83.class,args);
    }
}

业务类：

java 复制代码 
package com.atguigu.cloud.controller;
import com.atguigu.cloud.apis.PayFeignSentinelApi;
import com.atguigu.cloud.resp.ResultData;
import jakarta.annotation.Resource;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RestController;
import org.springframework.web.client.RestTemplate;
@RestController
public class OrderNacosController{
    @Resource
    private RestTemplate restTemplate;
    @Resource
    private PayFeignSentinelApi payFeignSentinelApi;

    @Value("${service-url.nacos-user-service}")
    private String serverURL;

    @GetMapping("/consumer/pay/nacos/{id}")
    public String paymentInfo(@PathVariable("id") Integer id){
        String result = restTemplate.getForObject(serverURL + "/pay/nacos/" + id, String.class);
        return result+"\t"+"    我是OrderNacosController83调用者。。。。。。";
    }

    @GetMapping(value = "/consumer/pay/nacos/get/{orderNo}")
    public ResultData getPayByOrderNo(@PathVariable("orderNo") String orderNo){
        return payFeignSentinelApi.getPayByOrderNo(orderNo);
    }
}

启动83服务

2.5.测试验证：

  • 9001正常启动后，再启动83，通过feign调用
  • 测试地址：
  • 3.sentinue流控为例，进行配置：测试发现频繁访问触发了Sentinue的流控规则，blockHandler起效
  • 4.9001宕机了，83通过feign调用，降级效果如下图
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