Spring Cloud的服务熔断（resilience4j）

为什么我会将Hystrix的熔断器换成resilience4j，因为尝试了半天发现虽然Hystrix的熔断器可以正常使服务降级，单个api接口可以返回fallback错误信息，但是不能使得服务熔断，具体原因可能就是注解失效，被放弃了，所以后面边将熔断器换成了当前的熔断器resilience4j

具体可以看看这篇博客，这篇博客详细写了如何使用resilience4j熔断器去使服务下降和服务熔断。OpenFeign熔断与降级_openfeign熔断降级-优快云博客

紧接上文的熔断器使服务降级

resilience4j的依赖下载：

        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-circuitbreaker-resilience4j</artifactId>
        </dependency>

架构如图所示：

IProductClientServiceFallbackFactory

package com.gaolang.fallback;

import com.gaolang.FeignClient.OrderFeignClient;
import com.gaolang.entities.CommonResult;
import com.gaolang.entities.Payment;
import org.springframework.cloud.openfeign.FallbackFactory;
import org.springframework.stereotype.Component;



public class IProductClientServiceFallbackFactory implements FallbackFactory<OrderFeignClient> {

    @Override
    public OrderFeignClient create(Throwable cause) {

        return new OrderFeignClient() {
            @Override
            public CommonResult create(Payment payment) {
                return new CommonResult<>(444,"服务降级返回,---PaymentFallbackService");
            }

            @Override
            public CommonResult getPaymentById(Long id) {
                return new CommonResult<>(444,"服务降级返回,---PaymentFallbackService");
            }

        };
    }
}

OrderFeignClient

package com.gaolang.FeignClient;


import com.gaolang.entities.CommonResult;
import com.gaolang.entities.Payment;
import com.gaolang.fallback.IProductClientServiceFallbackFactory;
import org.springframework.cloud.openfeign.FeignClient;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.PostMapping;

@FeignClient(value  = "cloud-provider-payment8001", fallbackFactory  = IProductClientServiceFallbackFactory.class) // 指定调用的服务名称
public interface OrderFeignClient {

    @PostMapping(value = "/payment/create")
    CommonResult create(Payment payment); // 创建支付记录

    @GetMapping(value = "/payment/{id}")
    CommonResult getPaymentById(@PathVariable("id") Long id); // 根据 ID 获取支付记录
}

FallbackConfig

package com.gaolang.config;

import com.gaolang.fallback.IProductClientServiceFallbackFactory;
import org.springframework.context.annotation.Bean;

public class FallbackConfig {
    @Bean
    public IProductClientServiceFallbackFactory iArticleClientFallbackFactory() {
        return new IProductClientServiceFallbackFactory();
    }
}

OrderMain80

package com.gaolang;


import com.gaolang.config.FallbackConfig;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.client.circuitbreaker.EnableCircuitBreaker;
import org.springframework.cloud.client.loadbalancer.LoadBalanced;
//import org.springframework.cloud.netflix.hystrix.EnableHystrix;
import org.springframework.cloud.openfeign.EnableFeignClients;
import org.springframework.context.annotation.Bean;
import org.springframework.web.client.RestTemplate;



@SpringBootApplication
@EnableFeignClients(basePackages = "com.gaolang", defaultConfiguration = FallbackConfig.class)
public class OrderMain80 {
    public static void main(String[] args) {
        SpringApplication.run(OrderMain80.class,args);
    }

    @LoadBalanced // 使 RestTemplate 自动支持 Ribbon 负载均衡
    @Bean
    public RestTemplate restTemplate() {
        return new RestTemplate();
    }
}

单启动该模块后，对api进行测试http://localhost:80/customer/payment/1后的结果如图所示：

成功使得服务熔断。