在Ribbon中添加Hystrix

在pom.xml添加

<dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-netflix-hystrix</artifactId>
</dependency>

在RibApplication上方
写上
@EnableHystrix
开启熔断器

@EnableHystrix
@SpringBootApplication
@EnableDiscoveryClient
public class RibApplication {

    public static void main(String[] args) {
        SpringApplication.run(RibApplication.class, args);
    }
}

修改Service

@Service
public class ClientService {

    @Autowired
    private RestTemplate restTemplate;

    //当程序出现错误时候熔断并调用hiError
    @HystrixCommand(fallbackMethod = "hiError")
    public String sayHi(String message) {
        System.out.println(message);
        return restTemplate.getForObject("http://client/hi?message="+message,String.class);
    }

    //写一段返回错误信息的方法
    public String hiError(String message){
        return String.format("Hi your message is : %s but request bad",message);
    }
}

在Feign中添加Hystrix

feign:
  hystrix:
    enabled: true

()最后)

spring:
  application:
    name: feign
server:
  port: 8789
feign:
  hystrix:
    enabled: true
eureka:
  client:
    service-url:
      defaultZone: http://127.0.0.1:8081/eureka/

Application无变化

@SpringBootApplication
@EnableFeignClients
@EnableDiscoveryClient
public class FeignApplication {

    public static void main(String[] args) {
        SpringApplication.run(FeignApplication.class, args);
    }
}

Service 下创建hystrix目录
并创建FeignHystrix.class

image.png

@Component
public class FeignHystrix implements FeignService {
    @Override
    public String sayHi(String message) {
        return String.format("Hi your message is err" + message);
    }
}

改造FeignService
加上fallback = 熔断回调方法

@FeignClient(value = "client",fallback = FeignHystrix.class)
public interface FeignService {

    @RequestMapping(value = "hi",method = RequestMethod.GET)
    String sayHi(@RequestParam(value = "message") String message);

}

添加熔断仪表盘监控

<dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-netflix-hystrix-dashboard</artifactId>
</dependency>

添加@EnableHystrixDashboard

@SpringBootApplication
@EnableFeignClients
@EnableDiscoveryClient
@EnableHystrixDashboard
public class FeignApplication {

    public static void main(String[] args) {
        SpringApplication.run(FeignApplication.class, args);
    }
}

创建HystrixDashboardConfiguration

@Configuration
public class HystrixDashboardConfiguration {

    @Bean
    public ServletRegistrationBean getServlet(){
        //创建servlet
        HystrixMetricsStreamServlet streamServlet = new HystrixMetricsStreamServlet();
        //servlet注册bean
        ServletRegistrationBean registrationBean = new ServletRegistrationBean(streamServlet);
        //servlet创建时机
        registrationBean.setLoadOnStartup(1);
        //servlet映射路径
        registrationBean.addUrlMappings("/hystrix.stream");
        //servlet名称
        registrationBean.setName("HystrixMetricsStreamServlet");
        return registrationBean;
    }
}

相当于创建了一个servlet
(对应字段对比)

image.png

image.png