springcloud學習-12 Hystrix斷路器【周陽springcloud2020學習筆記】

作用：

• 服務降級：
  程序運行異常、超時、服務熔斷觸發服務降級、線程池或信號量打滿也會導致服務降級
• 服務熔斷：
  類比保險絲達到最大服務訪問後，直接拒絕訪問，拉閘限電，然後調用服務降級的方法並返回友好提示
  服務的降級->進而熔斷->恢復調用鏈路
• 服務限流：秒殺高併發等操作，嚴禁一窩蜂的過來擁擠，大家排隊，一秒鐘N個，有序進行
  接近實時的監控

---

提供者hystrix-provider-payment8005

1.新建hystrix-provider-payment8005
2.pom

<dependencies>

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

    <!--eureka-client-->
    <dependency>
        <groupId>org.springframework.cloud</groupId>
        <artifactId>spring-cloud-starter-netflix-eureka-client</artifactId>
    </dependency>

    <!--公共模塊:通用工具包-->
    <dependency>
        <groupId>cn.chen.demo</groupId>
        <artifactId>api-common</artifactId>
        <version>${project.version}</version>
    </dependency>

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

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

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

    <!-- druid -->
    <dependency>
        <groupId>com.alibaba</groupId>
        <artifactId>druid-spring-boot-starter</artifactId>
    </dependency>

    <!-- mysql -->
    <dependency>
        <groupId>mysql</groupId>
        <artifactId>mysql-connector-java</artifactId>
    </dependency>

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

    <!-- 熱部署依賴 -->
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-devtools</artifactId>
        <scope>runtime</scope>
        <optional>true</optional>
    </dependency>

    <!-- lombok -->
    <dependency>
        <groupId>org.projectlombok</groupId>
        <artifactId>lombok</artifactId>
        <optional>true</optional>
    </dependency>

    <!-- test -->
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-test</artifactId>
        <scope>test</scope>
    </dependency>
</dependencies>

3.yml

server:
  port: 8005 # 端口號

spring:
  # 應用名稱
  application:
    name: hystrix-payment-service # 服務名稱

  # 數據源
  datasource:
    type: com.alibaba.druid.pool.DruidDataSource # 數據庫操作類型
    driver-class-name: org.gjt.mm.mysql.Driver # 數據庫驅動
    #url: jdbc:mysql://192.168.221.129:3306/demo2020?useUnicode=true&characterEncoding=utf-8&useSSL=false
    url: jdbc:mysql://localhost:3306/demo2020?useUnicode=true&characterEncoding=utf-8&useSSL=false
    username: root
    password: 123456

  # 是否支持熱部署
  devtools:
    restart:
      enabled: true

eureka:
  client:
    register-with-eureka: true
    fetchRegistry: true
    service-url:
      defaultZone: http://localhost:7001/eureka # 單機版
      #defaultZone: http://eureka7001.com:7001/eureka,http://eureka7002.com:7002/eureka  # 集羣版
  instance:
    instance-id: payment8005
    prefer-ip-address: true
    # eureka客戶端想服務端發動心跳的時間間隔，單位爲秒（默認是30秒）。開發的時候可以設置小一些，以保證服務關閉後註冊中心及時剔除服務
    lease-renewal-interval-in-seconds: 1
    # eureka服務端在收到最後一次心跳後等待時間上限，單位爲秒（默認是90秒）。開發時候設置小一些
    lease-expiration-duration-in-seconds: 2

mybatis:
  mapperLocations: classpath:mapper/*.xml #mapper文件
  type-aliases-package: cn.chen.cloud.entity  #所有entity別名所在包

4.主啓動

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

5.業務類
1)service

 @Service
 public class PaymentService {

 	/**
 	 * @Description 模擬訪問成功情況
 	 **/
 	public String IsOk(){
 		return "線程池："+Thread.currentThread().getName()+"，IsOk。";
 	}

 	/**
 	 * @Description 模擬訪問失敗情況
 	 **/
 	public String IsTimeOut(int timeNumber){
 		try {
 			TimeUnit.SECONDS.sleep(timeNumber);
 		}catch (Exception e) {
 			e.printStackTrace();
 		}
 		return "線程池："+Thread.currentThread().getName()+"，IsTimeOut，耗時(秒)"+timeNumber;
 	}
 }

2)controller

  @RestController
  @Slf4j
  @RequestMapping("/payment")
  public class PaymentController {

  	@Resource
  	private PaymentService paymentService;

  	@GetMapping("/hystrix/ok")
  	public String ok(){
  		String result = paymentService.IsOk();
  		log.info("*******result:"+result);
  		return result;
  	}
  	@GetMapping("/hystrix/timeout")
  	public String timeOut(){
  		String result = paymentService.IsTimeOut(3);
  		log.info("*******result:"+result);
  		return result;
  	}
  }

6.啓動7001（單機版）
啓動8005（Hystrix）

---

消費者hystrix-consumer-order80

1.新建hystrix-consumer-order80
2.pom依賴（參考consumer-order80）

 <dependencies>

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

         <!--openfeign -->
         <dependency>
             <groupId>org.springframework.cloud</groupId>
             <artifactId>spring-cloud-starter-openfeign</artifactId>
         </dependency>

         <!--eureka-client-->
         <dependency>
             <groupId>org.springframework.cloud</groupId>
             <artifactId>spring-cloud-starter-netflix-eureka-client</artifactId>
         </dependency>

         <!--公共模塊-->
         <dependency>
             <groupId>cn.chen.demo</groupId>
             <artifactId>api-common</artifactId>
             <version>${project.version}</version>
         </dependency>

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

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

         <!-- devtools -->
         <dependency>
             <groupId>org.springframework.boot</groupId>
             <artifactId>spring-boot-devtools</artifactId>
             <scope>runtime</scope>
             <optional>true</optional>
         </dependency>

         <!-- lombok -->
         <dependency>
             <groupId>org.projectlombok</groupId>
             <artifactId>lombok</artifactId>
             <optional>true</optional>
         </dependency>

         <!-- test -->
         <dependency>
             <groupId>org.springframework.boot</groupId>
             <artifactId>spring-boot-starter-test</artifactId>
             <scope>test</scope>
         </dependency>
     </dependencies>

3.yml配置（參考consumer-order80）

    server:
      port: 80

    spring:
      application:
        name: hystrix-order-consumer

    eureka:
      client:
        register-with-eureka: true
        fetchRegistry: true
        service-url:
          defaultZone: http://localhost:7001/eureka # 單機版
          #defaultZone: http://eureka7001.com:7001/eureka,http://eureka7002.com:7002/eureka  #集羣版
      instance:
        instance-id: order80
        prefer-ip-address: true

    payment:
      #url: http://localhost:8001
      server:
        name: http://payment-service

4.主啓動類

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

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