springcloud学习-12 Hystrix断路器【周阳springcloud2020学习笔记】

作用：

• 服务降级：
  程序运行异常、超时、服务熔断触发服务降级、线程池或信号量打满也会导致服务降级
• 服务熔断：
  类比保险丝达到最大服务访问后，直接拒绝访问，拉闸限电，然后调用服务降级的方法并返回友好提示
  服务的降级->进而熔断->恢复调用链路
• 服务限流：秒杀高并发等操作，严禁一窝蜂的过来拥挤，大家排队，一秒钟N个，有序进行
  接近实时的监控

---

提供者hystrix-provider-payment8005

1.新建hystrix-provider-payment8005
2.pom

<dependencies>

    
    <dependency>
        <groupId>org.springframework.cloudgroupId>
        <artifactId>spring-cloud-starter-netflix-hystrixartifactId>
    dependency>

    
    <dependency>
        <groupId>org.springframework.cloudgroupId>
        <artifactId>spring-cloud-starter-netflix-eureka-clientartifactId>
    dependency>

    
    <dependency>
        <groupId>cn.chen.demogroupId>
        <artifactId>api-commonartifactId>
        <version>${project.version}version>
    dependency>

    <dependency>
        <groupId>org.springframework.bootgroupId>
        <artifactId>spring-boot-starter-webartifactId>
    dependency>

    <dependency>
        <groupId>org.springframework.bootgroupId>
        <artifactId>spring-boot-starter-actuatorartifactId>
    dependency>

    <dependency>
        <groupId>org.mybatis.spring.bootgroupId>
        <artifactId>mybatis-spring-boot-starterartifactId>
    dependency>

    
    <dependency>
        <groupId>com.alibabagroupId>
        <artifactId>druid-spring-boot-starterartifactId>
    dependency>

    
    <dependency>
        <groupId>mysqlgroupId>
        <artifactId>mysql-connector-javaartifactId>
    dependency>

    
    <dependency>
        <groupId>org.springframework.bootgroupId>
        <artifactId>spring-boot-starter-jdbcartifactId>
    dependency>

    
    <dependency>
        <groupId>org.springframework.bootgroupId>
        <artifactId>spring-boot-devtoolsartifactId>
        <scope>runtimescope>
        <optional>trueoptional>
    dependency>

    
    <dependency>
        <groupId>org.projectlombokgroupId>
        <artifactId>lombokartifactId>
        <optional>trueoptional>
    dependency>

    
    <dependency>
        <groupId>org.springframework.bootgroupId>
        <artifactId>spring-boot-starter-testartifactId>
        <scope>testscope>
    dependency>
dependencies>

3.yml

server:
  port: 8005 # 端口号

spring:
  # 应用名称
  application:
    name: hystrix-payment-service # 服务名称

  # 数据源
  datasource:
    type: com.alibaba.druid.pool.DruidDataSource # 数据库操作类型
    driver-class-name: org.gjt.mm.mysql.Driver # 数据库驱动
    #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

  # 是否支持热部署
  devtools:
    restart:
      enabled: true

eureka:
  client:
    register-with-eureka: true
    fetchRegistry: true
    service-url:
      defaultZone: http://localhost:7001/eureka # 单机版
      #defaultZone: http://eureka7001.com:7001/eureka,http://eureka7002.com:7002/eureka  # 集群版
  instance:
    instance-id: payment8005
    prefer-ip-address: true
    # eureka客户端想服务端发动心跳的时间间隔，单位为秒（默认是30秒）。开发的时候可以设置小一些，以保证服务关闭后注册中心及时剔除服务
    lease-renewal-interval-in-seconds: 1
    # eureka服务端在收到最后一次心跳后等待时间上限，单位为秒（默认是90秒）。开发时候设置小一些
    lease-expiration-duration-in-seconds: 2

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

4.主启动

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

5.业务类
1)service

 @Service
 public class PaymentService {

 	/**
 	 * @Description 模拟访问成功情况
 	 **/
 	public String IsOk(){
 		return "线程池："+Thread.currentThread().getName()+"，IsOk。";
 	}

 	/**
 	 * @Description 模拟访问失败情况
 	 **/
 	public String IsTimeOut(int timeNumber){
 		try {
 			TimeUnit.SECONDS.sleep(timeNumber);
 		}catch (Exception e) {
 			e.printStackTrace();
 		}
 		return "线程池："+Thread.currentThread().getName()+"，IsTimeOut，耗时(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.启动7001（单机版）
启动8005（Hystrix）

---

消费者hystrix-consumer-order80

1.新建hystrix-consumer-order80
2.pom依赖（参考consumer-order80）

 <dependencies>

         
         <dependency>
             <groupId>org.springframework.cloudgroupId>
             <artifactId>spring-cloud-starter-netflix-hystrixartifactId>
         dependency>

         
         <dependency>
             <groupId>org.springframework.cloudgroupId>
             <artifactId>spring-cloud-starter-openfeignartifactId>
         dependency>

         
         <dependency>
             <groupId>org.springframework.cloudgroupId>
             <artifactId>spring-cloud-starter-netflix-eureka-clientartifactId>
         dependency>

         
         <dependency>
             <groupId>cn.chen.demogroupId>
             <artifactId>api-commonartifactId>
             <version>${project.version}version>
         dependency>

         <dependency>
             <groupId>org.springframework.bootgroupId>
             <artifactId>spring-boot-starter-webartifactId>
         dependency>

         <dependency>
             <groupId>org.springframework.bootgroupId>
             <artifactId>spring-boot-starter-actuatorartifactId>
         dependency>

         
         <dependency>
             <groupId>org.springframework.bootgroupId>
             <artifactId>spring-boot-devtoolsartifactId>
             <scope>runtimescope>
             <optional>trueoptional>
         dependency>

         
         <dependency>
             <groupId>org.projectlombokgroupId>
             <artifactId>lombokartifactId>
             <optional>trueoptional>
         dependency>

         
         <dependency>
             <groupId>org.springframework.bootgroupId>
             <artifactId>spring-boot-starter-testartifactId>
             <scope>testscope>
         dependency>
     dependencies>

3.yml配置（参考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 # 单机版
          #defaultZone: http://eureka7001.com:7001/eureka,http://eureka7002.com:7002/eureka  #集群版
      instance:
        instance-id: order80
        prefer-ip-address: true

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

4.主启动类

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

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