SpringCloud之Hystrix

1.什么是Hystrix

Hystix是Netflix开源的一个延迟和容错库，用于隔离访问远程服务、第三方库，防止出现级联失败

2.熔断器的工作机制

3.hytrix的入门demo

3.1pom文件

<dependencies>
        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>3.8.1</version>
            <scope>test</scope>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-netflix-eureka-client</artifactId>
            <version>1.4.3.RELEASE</version>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-actuator</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-netflix-hystrix</artifactId>
            <version>1.4.3.RELEASE</version>
        </dependency>
    </dependencies>

3.2application.yml

server:
  port: 8200
spring:
  application:
    name: springcloud-consumer-hy
eureka:
  client:
    serviceUrl:
      defaultZone: http://user:123@localhost:10000/eureka
  instance:
    prefer-ip-address: true
    ip-address: 127.0.0.1 # 指定自己的ip信息，不指定的话会自己寻找

3.3启动类

@SpringBootApplication
@EnableEurekaClient
@EnableCircuitBreaker
public class HyonsumerApplication {
    public static void main(String[] args) {
        SpringApplication.run(HyonsumerApplication.class,args);
    }
}

3.4修改消费者

import carry.shuai.pojo.User;
import com.netflix.appinfo.InstanceInfo;
import com.netflix.discovery.EurekaClient;
import com.netflix.hystrix.contrib.javanica.annotation.HystrixCommand;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RestController;
import org.springframework.web.client.RestTemplate;

@RestController
public class UserControllerConsoumer {


    @Autowired
    private RestTemplate restTemplate;

    @Autowired
    private EurekaClient eurekaClient;

    @GetMapping("/getUser")
    @HystrixCommand(fallbackMethod = "shibai")
    public User getUser(){
        String url = eurekaClient.getNextServerFromEureka("springcloud-privider", false).getHomePageUrl();
      //  String url = "192.168.247.1:8001/";
        //url.replace("/","%2F");
        System.out.println("url:"+url+"getUserById");
        //User user = restTemplate.getForObject(url + "getUserById", User.class);
        //System.out.println("user:"+user);
        return restTemplate.getForObject(url+"getUserById",User.class);
    }
    //失败后调用的方法
    public User shibai(){//参数需要和原方法一致
        User user = new User();
        user.setId(-400L);
        user.setName("jeery");
        return user;
    }
}

4.设置hytrix的超时时长

hystrix:
  command:
  	default:
        execution:
          isolation:
            thread:
              timeoutInMillisecond: 6000 # 设置hystrix的超时时间为6000ms

5.别的springcloud组件

1.eureake:https://blog.youkuaiyun.com/oldshaui/article/details/86589606

2.ribbon :https://blog.youkuaiyun.com/oldshaui/article/details/86593504