06-CircuitBreaker断路器 06-CircuitBreaker断路器

1、介绍

Spring Cloud Circuit breaker provides an abstraction across different circuit breaker implementations. It provides a consistent API to use in your applications allowing you the developer to choose the circuit breaker implementation that best fits your needs for your app.

Spring Cloud断路器提供了一个跨不同断路器的抽象实现。它提供了在您的应用程序中使用的一致的API，允许您的开发人员选择最适合您的应用程序需要的断路器实现。
支持断路器实现有以下几种

Netfix Hystrix (Spring Cloud官方已经不予支持)
Resilience4J （支持）
Sentinel
Spring Retry

2、快速开始 【06-CircuitBreaker断路器】pom.xml
maven依赖配置文件，如下：

4.0.0org.springframework.boot spring-boot-starter-parent 2.6.4 com.mindasoft spring-cloud-circuitbreaker-consumer 0.0.1-SNAPSHOT spring-cloud-circuitbreaker-consumer Demo project for Spring BootUTF-8UTF-8 1.8 2021.0.1 org.springframework.cloud spring-cloud-starter-netflix-eureka-client org.springframework.cloud spring-cloud-starter-circuitbreaker-resilience4j org.springframework.boot spring-boot-starter-web org.springframework.boot spring-boot-starter-test test org.springframework.cloud spring-cloud-dependencies ${spring-cloud.version} pom import org.springframework.boot spring-boot-maven-plugin nexus-aliyun Nexus aliyun https://maven.aliyun.com/repository/public defaultfalse true nexus-aliyun Nexus aliyun https://maven.aliyun.com/repository/publicfalse true

比上个项目多了如下配置：

org.springframework.cloud spring-cloud-starter-circuitbreaker-resilience4j

使用resilience4j 实现断路器。
application.properties

server.port=9004# 服务注册中心地址 eureka.client.service-url.defaultZone=http://localhost:9000/eureka/# 服务名称 spring.application.name=circuitbreaker-customer

SpringCloudCircuitBreakerConsumerApplication

package com.mindasoft; import io.github.resilience4j.circuitbreaker.CircuitBreakerConfig; import io.github.resilience4j.timelimiter.TimeLimiterConfig; import org.springframework.boot.SpringApplication; import org.springframework.boot.autoconfigure.SpringBootApplication; import org.springframework.cloud.circuitbreaker.resilience4j.Resilience4JCircuitBreakerFactory; import org.springframework.cloud.circuitbreaker.resilience4j.Resilience4JConfigBuilder; import org.springframework.cloud.client.circuitbreaker.Customizer; import org.springframework.cloud.client.discovery.EnableDiscoveryClient; import org.springframework.cloud.client.loadbalancer.LoadBalanced; import org.springframework.context.annotation.Bean; import org.springframework.web.client.RestTemplate; import java.time.Duration; @EnableDiscoveryClient // Eureka Discovery Client 标识 @SpringBootApplication public class SpringCloudCircuitBreakerConsumerApplication {// 开启负载均衡的功能 @Bean @LoadBalanced RestTemplate restTemplate() { return new RestTemplate(); }@Bean public Customizer defaultCustomizer() { return factory -> factory.configureDefault(id -> new Resilience4JConfigBuilder(id) .timeLimiterConfig(TimeLimiterConfig.custom().timeoutDuration(Duration.ofSeconds(3)).build()) .circuitBreakerConfig(CircuitBreakerConfig.ofDefaults()) .build()); }public static void main(String[] args) { SpringApplication.run(SpringCloudCircuitBreakerConsumerApplication.class, args); }}

ConsumerController

package com.mindasoft.consumer; import org.slf4j.Logger; import org.slf4j.LoggerFactory; import org.springframework.beans.factory.annotation.Autowired; import org.springframework.cloud.client.circuitbreaker.CircuitBreakerFactory; import org.springframework.web.bind.annotation.RequestMapping; import org.springframework.web.bind.annotation.RestController; import org.springframework.web.client.RestTemplate; /** * Created by huangmin on 2017/11/10 14:50. */ @RestController public class ConsumerController {private static final Logger LOGGER = LoggerFactory.getLogger(ConsumerController.class); @Autowired private RestTemplate restTemplate; // HTTP 访问操作类 @Autowired private CircuitBreakerFactory circuitBreakerFactory; @RequestMapping("/hello") public String hello() { String providerMsg = circuitBreakerFactory.create("hello") .run(() -> restTemplate.getForObject("http://PROVIDER-SERVICE/hello", String.class), throwable -> "CircuitBreaker fallback msg"); return "Hello,I'm Customer! msg from provider : " + providerMsg; }}

启动eureka server和本项目，访问http://127.0.0.1:9004/hello
页面打印如下：