1.服務熔斷

1.1引入坐標

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

1.2 主啟動類標識

package org.maple;

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.netflix.eureka.EnableEurekaClient;

/**
 * @author
 
 mapleins
 * @Date 2019-01-12 17:13
 * @Desc
 **/
@SpringBootApplication
@EnableEurekaClient
@EnableDiscoveryClient//服務發現 可以看到服務信息
@EnableCircuitBreaker //開啟斷路器
public class App_Provider_Dept_8001_Hystrix {

    public static void main(String[] args) {
        SpringApplication.run(App_Provider_Dept_8001_Hystrix.
 
class,args);
    }
}

1.3 添加熔斷方法

    @GetMapping("/dept/get/{id}")
    //出錯調用hystrixCommand中的方法
    @HystrixCommand(fallbackMethod = "hystrix_get")
    public Dept get(@PathVariable("id") Long id) {
        Dept dept = service.find(id);
        if (null == dept) {
            throw new RuntimeException("該id"+id+"沒有對應信息");
        }
        return dept;
    }

    public Dept hystrix_get(@PathVariable("id") Long id){
        return new Dept().setDeptNo(id).setDName("該id"+id+"沒有對應的信息，null--@HystrixCommand").setDb_source("no this database in Mysql");
    }

1.4 訪問

2.服務降級

　　添加服務熔斷，會造成方法翻倍，每一個接口都需要一個服務熔斷，此時就可以使用服務降級，類似異常處理+切面編程

2.1 針對接口編寫回調函數工廠，在接口上聲明工廠類

　　之前將服務的調用通過feign來實現接口調用，現在對接口操作實現服務降級，對整個方法進行統一管理，實現解耦

package org.maple.service;

import feign.hystrix.FallbackFactory;
import org.maple.entity.Dept;
import org.springframework.stereotype.Component;

import java.util.List;

/**
 * @author mapleins
 * @Date 2019-01-13 12:01
 * @Desc 服務降級
 **/
@Component
public class DeptClientServiceFallbackFactory implements FallbackFactory<DeptClientService> {

    @Override
    public DeptClientService create(Throwable throwable) {

        return new DeptClientService() {
            @Override
            public boolean add(Dept dept) {
                return false;
            }

            @Override
            public Dept get(Long id) {
                return new Dept().setDeptNo(id).setDName("該服務已經關閉").setDb_source("no this database in Mysql");
            }

            @Override
            public List<Dept> list() {
                return null;
            }
        };
    }
}

package org.maple.service;

import org.maple.entity.Dept;
import org.springframework.cloud.openfeign.FeignClient;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.RequestBody;

import java.util.List;

/**
 * @author mapleins
 * @Date 2019-01-12 23:10
 * @Desc 通過接口和註解 面向接口編程訪問微服務
 **/
//@FeignClient("ms-provider-dept")
@FeignClient(value = "ms-provider-dept",fallbackFactory = DeptClientServiceFallbackFactory.class) //服務降級類
public interface DeptClientService {

    @PostMapping("/dept/add")
    boolean add(@RequestBody Dept dept);

    @GetMapping("/dept/get/{id}")
    Dept get(@PathVariable("id") Long id);

    @GetMapping("/dept/list")
    List<Dept> list();

}

2.2 在調用接口的消費方開啟hystrix

feign:
  hystrix:
    enabled: true #開啟服務降級

2.3 調用

開啟2個eureka server,1個provider-dept,1個consumer

關閉provider

3.Hystrix Dashboard 準實時調用監控

3.1 操作

需要監控的服務必須依賴：

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

新建一個hystrix-dashboard工程

<?xml version="1.0" encoding="UTF-8"?>
<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/xsd/maven-4.0.0.xsd">
    <parent>
        <artifactId>spring-cloud-learning</artifactId>
        <groupId>org.org.maple</groupId>
        <version>0.0.1-SNAPSHOT</version>
    </parent>
    <modelVersion>4.0.0</modelVersion>

    <artifactId>ms-consumer-hystrix-dashboard</artifactId>

    <dependencies>
        <dependency>
            <groupId>org.org.maple</groupId>
            <artifactId>ms-common-api</artifactId>
            <version>0.0.1-SNAPSHOT</version>
        </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-hystrix</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-netflix-hystrix-dashboard</artifactId>
        </dependency>
    </dependencies>

</project>

server:
  port: 9001

package org.maple;

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

/**
 * @author mapleins
 * @Date 2019-01-13 12:44
 * @Desc
 **/
@SpringBootApplication
@EnableHystrixDashboard //開啟儀表盤
public class App_Hystrix_Dashboard_9001 {

    public static void main(String[] args) {
        SpringApplication.run(App_Hystrix_Dashboard_9001.class,args);
    }
}

3.2 啟動界面

如果訪問路徑404，則需要在監控的服務中配置一個Bean

    @Bean
    public ServletRegistrationBean getServlet() {
        HystrixMetricsStreamServlet streamServlet = new HystrixMetricsStreamServlet();
        ServletRegistrationBean registrationBean = new ServletRegistrationBean(streamServlet);
        registrationBean.setLoadOnStartup(1);
        registrationBean.addUrlMappings("/hystrix.stream");
        registrationBean.setName("HystrixMetricsStreamServlet");
        return registrationBean;
    }

<Spring Cloud>入門五 hystrix