package com.atm.cloud;

import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.boot.builder.SpringApplicationBuilder;
import org.springframework.boot.web.servlet.ServletComponentScan;
import org.springframework.cloud.client.circuitbreaker.EnableCircuitBreaker;
import org.springframework.cloud.client.loadbalancer.LoadBalanced;
import org.springframework.cloud.netflix.eureka.EnableEurekaClient;
import org.springframework.cloud.netflix.feign.EnableFeignClients;
import org.springframework.context.annotation.Bean;
import org.springframework.web.client.RestTemplate;

@SpringBootApplication
@EnableEurekaClient
@EnableCircuitBreaker//打开Hystrix断路器
@ServletComponentScan//扫描缓存
@EnableFeignClients//打开Feign注解
public class HystrixInvokerApp {

    @Bean
    @LoadBalanced
    public RestTemplate getRestTemplate() {
        return new RestTemplate();
    }

    public static void main(String[] args) {
        new SpringApplicationBuilder(HystrixInvokerApp.class).web(true).run(
                args);
    }
}

1.3、新建Feign接口（测试回退）

1.3.1、回顾服务提供者MyRestController

去调用服务提供者的接口，以下代码是服务提供者的接口代码

package com.atm.cloud;

import org.springframework.http.MediaType;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.ResponseBody;
import org.springframework.web.bind.annotation.RestController;

@RestController
public class MyRestController {

    @RequestMapping(value = "/person/{personId}", method = RequestMethod.GET, produces = MediaType.APPLICATION_JSON_VALUE)
    public Person findPerson(@PathVariable("personId") Integer personId) {
        Person person = new Person();

        person.setId(personId);
        person.setAge(18);
        person.setName("atm");

        return person;
    }

    @GetMapping("/hello")
    @ResponseBody
    public String sayHello(){
        return "Hello World!";
    }

}

1.3.2、回顾服务调用者HelloClient

package com.atm.cloud.feignCtr;

import org.springframework.cloud.netflix.feign.FeignClient;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;

@FeignClient("atm-eureka-hystrix-provider")
public interface HelloClient {

    @RequestMapping(method=RequestMethod.GET,value="/hello")
    String sayHello();
}

1.3.3、回顾服务调用者FeignController

package com.atm.cloud.feignCtr;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.RestController;

@RestController
public class FeignController {

    @Autowired
    private HelloClient helloClient;

    @RequestMapping(value = "ivHello", method = RequestMethod.GET)
    public String ivHello() {
        return helloClient.sayHello();
    }
}

1.3.4、修改application.yml

server:
 port: 9000
spring:
 application:
  name: atm-eureka-hystrix-invoker
##开启feign开关
feign:
  hystrix:
    enabled: true
eureka:
 client:
  serviceUrl:
   defaultZone: http://localhost:8761/eureka/

1.3.5、新增HelloClientFallBack

package com.atm.cloud.feignCtr;

import org.springframework.stereotype.Component;

//HelloClient类去Spring容器中寻找HelloClientFallBack
//所以添加注解Component
@Component
public class HelloClientFallBack implements HelloClient {

    public String sayHello() {
        return "fallBack Hello";
    }

}

1.3.6、修改HelloClient

package com.atm.cloud.feignCtr;

import org.springframework.cloud.netflix.feign.FeignClient;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;

//当HellClien访问atm-eureka-hystrix-provider失败时，需要有一个后备服务
//后备服务需要实现该接口
@FeignClient(name = "atm-eureka-hystrix-provider", fallback = HelloClientFallBack.class)
public interface HelloClient {

    @RequestMapping(method = RequestMethod.GET, value = "/hello")
    String sayHello();
}

1.4、测试断路器

断路器打开的要求
1. 10秒内连续20个同样的请求
2. 失败率过50%
断路器关闭
1. 休眠期5分钟
2. 5分钟后尝试请求，请求成功则关闭

1.4.1、服务提供者MyRestController

package com.atm.cloud;

import org.springframework.http.MediaType;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.ResponseBody;
import org.springframework.web.bind.annotation.RestController;

@RestController
public class MyRestController {

    @GetMapping("/tmhello")
    @ResponseBody
    public String timeOutHello() throws InterruptedException {
        // 此方法处理最少需要1s
        Thread.sleep(1000);
        return "TimeOut Hello";
    }

}

1.4.2、服务调用者HelloClient

package com.atm.cloud.feignCtr;

import org.springframework.cloud.netflix.feign.FeignClient;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;

//当HellClien访问atm-eureka-hystrix-provider失败时，需要有一个后备服务
//后备服务需要实现该接口
@FeignClient(name = "atm-eureka-hystrix-provider", fallback = HelloClientFallBack.class)
public interface HelloClient {

    @RequestMapping(method = RequestMethod.GET, value = "/tmhello")
    String toHello();
}

package com.atm.cloud.feignCtr;

import org.springframework.stereotype.Component;

@Component
public class HelloClientFallBack implements HelloClient {

    public String toHello() {
        return "fallBack timeOut Hello";
    }

}

1.4.3、服务调用者FeignController

package com.atm.cloud.feignCtr;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.RestController;

import com.netflix.hystrix.HystrixCircuitBreaker;
import com.netflix.hystrix.HystrixCommandKey;

@RestController
public class FeignController {

    @Autowired
    private HelloClient helloClient;

    @RequestMapping(value = "tmHello", method = RequestMethod.GET)
    public String tmHello() {
        String result = helloClient.toHello();
        HystrixCircuitBreaker breaker = HystrixCircuitBreaker.Factory
                .getInstance(HystrixCommandKey.Factory
                        .asKey("HelloClient#toHello()"));
        System.out.println("断路器状态：" + breaker.isOpen());
        return result;
    }
}

1.4.4、服务调用者application.yml

server:
 port: 9000
spring:
 application:
  name: atm-eureka-hystrix-invoker
feign:
  hystrix:
    enabled: true
hystrix:
  command:
    ##全局方法使用default
    HelloClient#toHello():
      execution:
        isolation:
          thread: 
          ##超时时间
            timeoutInMilliseconds: 500
      circuitBreaker:
      ##每秒3次请求
        requestVolumeThreshold: 3
eureka:
 client:
  serviceUrl:
   defaultZone: http://localhost:8761/eureka/

1.4.5、服务调用者HttpClientMain

package com.atm.cloud.feignCtr;

import org.apache.http.HttpResponse;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.impl.client.CloseableHttpClient;
import org.apache.http.impl.client.HttpClients;
import org.apache.http.util.EntityUtils;

public class HttpClientMain {

    public static void main(String[] args) throws Exception{
        final CloseableHttpClient httpclient = HttpClients.createDefault();
        final String url = "http://localhost:9000/tmHello";

        for(int i = 0; i < 6; i++) {
            Thread t = new Thread() {

                @Override
                public void run() {
                    try {
                        HttpGet httpget = new HttpGet(url);
                        HttpResponse response = httpclient.execute(httpget);
                        System.out.println(EntityUtils.toString(response.getEntity()));
                    } catch (Exception e ) {
                        e.printStackTrace();
                    }
                }               
            };
            t.start();
        }
        Thread.sleep(15000);
    }
}

1.5、Hystrix监控

客户端被监控
谁去监控客户端，一般由其他项目监控，这里新建一个maven项目进行监控

1.5.1、服务提供者引入依赖

<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-actuator</artifactId>
    <version>1.5.3.RELEASE</version>
</dependency>

1.5.2、监控引入依赖

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <groupId>com.atm.cloud</groupId>
    <artifactId>atm_eureka_hystrix_visit</artifactId>
    <packaging>war</packaging>
    <version>0.0.1-SNAPSHOT</version>
    <name>atm_eureka_hystrix_visit Maven Webapp</name>
    <url>http://maven.apache.org</url>

    <dependencyManagement>
        <dependencies>
            <dependency>
                <groupId>org.springframework.cloud</groupId>
                <artifactId>spring-cloud-dependencies</artifactId>
                <version>Dalston.SR1</version>
                <type>pom</type>
                <scope>import</scope>
            </dependency>
        </dependencies>
    </dependencyManagement>

    <dependencies>
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-hystrix-dashboard</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-hystrix</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-actuator</artifactId>
            <version>1.5.3.RELEASE</version>
        </dependency>
    </dependencies>
    <build>
        <finalName>atm_eureka_hystrix_visit</finalName>
    </build>
</project>

1.5.3、监控启动

监控服务调用者

package com.atm.cloud;

import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.boot.builder.SpringApplicationBuilder;
import org.springframework.cloud.netflix.hystrix.dashboard.EnableHystrixDashboard;

@SpringBootApplication
@EnableHystrixDashboard
public class HystrixVisitApp {

    public static void main(String[] args) {
        new SpringApplicationBuilder(HystrixVisitApp.class).properties(
                "server.port=8082").run(args);
    }

}