前言

項目地址：https://github.com/SunSmileAZY/anzy-master-v1

用的模塊：service-eruka、demo-cloud-01、demo-hystrix

一、新建一個Eureka Server服務

核心依賴包：

<code>    <dependencies>
        <dependency>
            <groupid>org.springframework.cloud/<groupid>
            <artifactid>spring-cloud-starter-netflix-eureka-server/<artifactid>
        /<dependency>
    /<dependencies>/<code>

啟動類：

<code>package com.anzy.cloud.eruka;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.boot.autoconfigure.amqp.RabbitAutoConfiguration;
import org.springframework.boot.autoconfigure.data.elasticsearch.ElasticsearchAutoConfiguration;
import org.springframework.boot.autoconfigure.data.mongo.MongoDataAutoConfiguration;
import org.springframework.boot.autoconfigure.data.redis.RedisAutoConfiguration;
import org.springframework.boot.autoconfigure.jdbc.DataSourceAutoConfiguration;
import org.springframework.boot.autoconfigure.mongo.MongoAutoConfiguration;
import org.springframework.boot.autoconfigure.orm.jpa.HibernateJpaAutoConfiguration;
import org.springframework.cloud.netflix.eureka.server.EnableEurekaServer;

/**
 * ServerEurekaApplication
 *
 * @author anzy
 * @date 2018-05-01
 */
@SpringBootApplication(exclude = {
        DataSourceAutoConfiguration.class,
        HibernateJpaAutoConfiguration.class,
        ElasticsearchAutoConfiguration.class,
        RabbitAutoConfiguration.class,
        RedisAutoConfiguration.class,
        MongoAutoConfiguration.class,
        MongoDataAutoConfiguration.class})
@EnableEurekaServer 

public class ServerEurekaApplication {
    public static void main(String[] args) {
        SpringApplication.run(ServerEurekaApplication.class, args);
    }
}/<code>

啟動項目：

瀏覽器輸入127.0.0.1:20000

二、創建服務提供端demo-cloud-01

提供服務接口：

<code>package com.anzy.cloud.cloud01.product;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.cloud.client.ServiceInstance;
import org.springframework.cloud.client.discovery.DiscoveryClient;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;
import org.springframework.web.client.RestTemplate;

import java.util.List;
import java.util.Random;

/**
 * @author anzy
 * @version 1.0
 * @date 2020/3/11 20:50
 **/
@RestController
@RequestMapping(value = "/product")
public class ProductController {

    @Autowired
    RestTemplate restTemplate;

    @Autowired
    private DiscoveryClient discoveryClient;

    @GetMapping("/list")
    public String list(){
        List<serviceinstance> serviceInstance = discoveryClient.getInstances("DEMO-CLOUD-01");
        System.out.println(serviceInstance);
\t\t\t // 隨機睡眠模擬超時，斷路器默認2000ms
        int sleepTime = new Random().nextInt(3000);
        System.out.println("======== sleepTime: " + sleepTime);
        try {
            Thread.sleep(sleepTime);
        } catch (InterruptedException e) { 

            e.printStackTrace();
        }

        return "成功調用demo-cloud-01 服務，我是商品列表";
    }
}
/<serviceinstance>/<code>

三、創建服務調用者demo-hystrix

斷路器需要引入spring-cloud-starter-netflix-hystrix包

<code>
        <dependency>
            <groupid>org.springframework.cloud/<groupid>
            <artifactid>spring-cloud-starter-netflix-hystrix/<artifactid>
        /<dependency>/<code>

開啟斷路器，在main類中開啟@EnableCircuitBreaker

<code>import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.boot.autoconfigure.amqp.RabbitAutoConfiguration;
import org.springframework.boot.autoconfigure.data.elasticsearch.ElasticsearchAutoConfiguration;
import org.springframework.boot.autoconfigure.data.mongo.MongoDataAutoConfiguration;
import org.springframework.boot.autoconfigure.data.redis.RedisAutoConfiguration;
import org.springframework.boot.autoconfigure.mongo.MongoAutoConfiguration;
import org.springframework.cloud.client.circuitbreaker.EnableCircuitBreaker;
import org.springframework.cloud.client.discovery.EnableDiscoveryClient;
import org.springframework.cloud.client.loadbalancer.LoadBalanced;
import org.springframework.cloud.openfeign.EnableFeignClients;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.ComponentScan;
import org.springframework.transaction.annotation.EnableTransactionManagement;
import org.springframework.web.client.RestTemplate;

/**
 * ServerEurekaApplication
 *
 * @author anzy
 * @date 2018-05-01
 */
@SpringBootApplication(exclude = {
        ElasticsearchAutoConfiguration.class,
        RabbitAutoConfiguration.class,
        RedisAutoConfiguration.class, 

        MongoAutoConfiguration.class,
        MongoDataAutoConfiguration.class})
@EnableTransactionManagement // 事務
//@EnableEurekaClient // @EnableEurekaClient只適用於Eureka作為註冊中心，@EnableDiscoveryClient 可以是其他註冊中心。
@EnableDiscoveryClient
@EnableCircuitBreaker
@EnableFeignClients(basePackages = {"com.anzy.cloud"})
@ComponentScan(basePackages = {"com.anzy.cloud"})
public class DemoHystrixApplication {
    public static void main(String[] args) {
        SpringApplication.run(DemoHystrixApplication.class, args);
    }

    @Bean
    @LoadBalanced
    RestTemplate restTemplate(){
        return new RestTemplate();
    }
}/<code>

<code>package com.anzy.cloud.hystrix.user;

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.RequestMapping;
import org.springframework.web.bind.annotation.RestController;
import org.springframework.web.client.RestTemplate;

/**
 * 斷路器使用
 * @author anzy
 * @version 1.0
 * @date 2020/1/18 20:51
 **/
@RestController
@RequestMapping(value = "/user")
public class UserController {

    @Autowired
    RestTemplate restTemplate;

    @HystrixCommand(fallbackMethod = "productListFallback")
    @GetMapping("/product/list")
    public String productList(){
        return restTemplate.getForEntity("http://DEMO-CLOUD-01/product/list",String.class).getBody().toString();
    }
    // 服務不可能或者超時調用此方法 

    public String productListFallback(){
        return "DEMO-CLOUD-01 服務崩掉了";
    }

}
/<code>

四、進行測試

打開postman調用 /user/product/list 接口

調用成功未超時

調用失敗

具體代碼可以看一下項目地址，直接運行service-eruka、demo-cloud-01、demo-hystrix三個項目即可，自己可以修改一下對應的配置。

本文主要是做一個斷路器的入門認識一下hystrix，後面將會講解具體的原理。

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關鍵字: 瀏覽器 容錯 斷路器