一 新建项目microservice-consumer-movie-ribbon-hystrix
二 为项目添加以下依赖
<dependency> <groupId>org.springframework.cloud</groupId> <artifactId>spring-cloud-starter-hystrix</artifactId> </dependency>
三 在启动类上添加注解@EnableCircuitBreaker或@Enablehystrix,从而为项目添加断路器功能
package com.itmuch.cloud.study; import org.springframework.boot.SpringApplication; import org.springframework.boot.autoconfigure.SpringBootApplication; import org.springframework.cloud.client.circuitbreaker.EnableCircuitBreaker; 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; @EnableDiscoveryClient @SpringBootApplication @EnableCircuitBreaker public class ConsumerMovieApplication { @Bean @LoadBalanced public RestTemplate restTemplate() { return new RestTemplate(); } public static void main(String[] args) { SpringApplication.run(ConsumerMovieApplication.class, args); } }
四 修改MovieController,让其中的findByid方法具有容错能力
package com.itmuch.cloud.study.user.controller; import org.slf4j.Logger; import org.slf4j.LoggerFactory; import org.springframework.beans.factory.annotation.Autowired; import org.springframework.cloud.client.ServiceInstance; import org.springframework.cloud.client.loadbalancer.LoadBalancerClient; 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; import com.itmuch.cloud.study.user.entity.User; import com.netflix.hystrix.contrib.javanica.annotation.HystrixCommand; @RestController public class MovieController { private static final Logger LOGGER = LoggerFactory.getLogger(MovieController.class); @Autowired private RestTemplate restTemplate; @Autowired private LoadBalancerClient loadBalancerClient; @HystrixCommand(fallbackMethod = "findByIdFallback") @GetMapping("/user/{id}") public User findById(@PathVariable Long id) { return this.restTemplate.getForObject("http://microservice-provider-user/" + id, User.class); } public User findByIdFallback(Long id) { User user = new User(); user.setId(-1L); user.setName("默认用户"); return user; } @GetMapping("/log-user-instance") public void logUserInstance() { ServiceInstance serviceInstance = this.loadBalancerClient.choose("microservice-provider-user"); // 打印当前选择的是哪个节点 MovieController.LOGGER.info("{}:{}:{}", serviceInstance.getServiceId(), serviceInstance.getHost(), serviceInstance.getPort()); } }
五 测试
1 启动eureka
2 启动user微服务
3 启动movie微服务
4 访问http://localhost:8010/user/1,结果如下
{"id":1,"username":"account1","name":"张三","age":20,"balance":100.00}
5 停止user微服务
6 再次访问http://localhost:8010/user/1,结果如下
{"id":-1,"username":null,"name":"默认用户","age":null,"balance":null}
说明当前微服务不可用,进入回退方法。