一、服务端配置服务降级
1）、相关依赖
<dependency><groupId>org.springframework.cloud</groupId><artifactId>spring-cloud-starter-netflix-hystrix</artifactId>
</dependency>
<dependency><groupId>org.springframework.cloud</groupId><artifactId>spring-cloud-starter-netflix-eureka-client</artifactId>
</dependency>2）、启动类开启@EnableCircuitBreaker
@SpringBootApplication
@EnableEurekaClient
@EnableCircuitBreaker
public class PaymentHystrixMain8001 {public static void main(String[] args) {SpringApplication.run(PaymentHystrixMain8001.class,args);}
}3）、业务类开启服务降级@HystrixCommand
@Service
public class PaymentService {public String paymentInfoOk(Integer id) {return "线程池："+Thread.currentThread().getName()+" paymentInfoOk,id:"+id;}@HystrixCommand(fallbackMethod = "paymentInfoTimeOutHandler",commandProperties = {@HystrixProperty(name = "execution.isolation.thread.timeoutInMilliseconds",value = "5000")})public String paymentInfoTimeOut(Integer id) throws InterruptedException {// int age=1/0;TimeUnit.SECONDS.sleep(3);return "线程池："+Thread.currentThread().getName()+" paymentInfoTimeOut,id:"+id+"，耗时3秒钟";}public String paymentInfoTimeOutHandler(Integer id){return "线程池："+Thread.currentThread().getName()+" paymentInfoTimeOut繁忙请稍后重试,id:"+id+"，服务降级";}}二、客户端配置服务降级
1）、相关依赖
<dependency><groupId>org.springframework.cloud</groupId><artifactId>spring-cloud-starter-netflix-hystrix</artifactId>
</dependency>
<dependency><groupId>org.springframework.cloud</groupId><artifactId>spring-cloud-starter-openfeign</artifactId>
</dependency>
<dependency><groupId>org.springframework.cloud</groupId><artifactId>spring-cloud-starter-netflix-eureka-client</artifactId>
</dependency>2）、全局配置
server:port: 80
spring:application:name: cloud-order-serviceeureka:client:#表示是否将自己注册进Eureka Server 默认为trueregister-with-eureka: true#是否从Eureka Server抓取已有的注册信息，默认为true。单节点无所谓。集群必须设置为true才能配合ribbon使用负载均衡fetch-registry: trueservice-url:defaultZone: http://eureka7001.com:7001/eureka/,http://eureka7002.com:7002/eureka/#设置Feign客户端连接超时时间(openFeign默认支持ribbon)
ribbon:#指的是建立连接所用时间，使用于网络状态正常情况下，两端连接所用时间ReadTimeout: 5000#指的是建立连接后从服务器读取到可用资源所用的时间ConnectTimeout: 5000
feign:hystrix:enabled: true3）、业务类开启服务降级@HystrixCommand
@DefaultProperties指定全局的，@HystrixCommand指定特定的
@RestController
@Slf4j
@DefaultProperties(defaultFallback = "paymentInfoGlobalTimeOutHandler")
public class PaymentHystrixController {@Resourceprivate PaymentHystrxFeign paymentHystrxFeign;@GetMapping("/payment/hystrix/ok/{id}")public String paymentInfoOk(@PathVariable("id") Integer id){return paymentHystrxFeign.paymentInfoOk(id);}/* @HystrixCommand(fallbackMethod = "paymentInfoTimeOutHandler",commandProperties = {@HystrixProperty(name = "execution.isolation.thread.timeoutInMilliseconds",value = "3000")})*/@HystrixCommand(commandProperties = {@HystrixProperty(name = "execution.isolation.thread.timeoutInMilliseconds",value = "3000")})@GetMapping("/payment/hystrix/timeout/{id}")public String paymentInfoTimeOut(@PathVariable("id") Integer id){int agg=1/0;return paymentHystrxFeign.paymentInfoTimeOut(id);}public String paymentInfoTimeOutHandler(@PathVariable("id")Integer id){return "线程池："+Thread.currentThread().getName()+" 特定服务降级，繁忙请稍后重试,id:"+id+"，服务降级";}public String paymentInfoGlobalTimeOutHandler(){return "线程池："+Thread.currentThread().getName()+" 全局服务降级，繁忙请稍后重试,id:服务降级";}
}
3)、测试服务降级
