Spring Cloud Hystrix项目实践和Hystrix监控

一、Hystrix项目实践

1、在Cinema影院工程中增加依赖

        <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>

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

　　

2、配置属性

server:
  port: 8301

eureka:
  client:
    service-url:
      defaultZone: http://localhost:8761/eureka/


management:
  endpoints:
    web:
      exposure:
        exclude: "*"

spring:
  application:
    name: cinema-service
  datasource:
    url: jdbc:mysql://127.0.0.1:3306/springclouddeep?autoReconnect=true&useUnicode=true&characterEncoding=utf8&zeroDateTimeBehavior=CONVERT_TO_NULL&useSSL=false&serverTimezone=UTC
    username: root
    password: 123456
    filters: log4j, wall, mergeState
mybatis-plus:
  mapper-locations: classpath*:com/example/springclouddeep/**/xml/*Mapper.xml
  global-config:
    id-type: 0
    db-column-underline: false
    refresh-mapper: true

　　

3、增加注解

4、对方法配置Hystrix 

ignoreExceptions的配置CommonServiceException，当抛出CommonServiceException，不做降级处理。

    @HystrixCommand(fallbackMethod = "fallbackMethod",
        commandProperties = {
                @HystrixProperty(name = "execution.isolation.strategy", value = "THREAD"),
                @HystrixProperty(name = "execution.isolation.thread.timeoutInMilliseconds", value= "1000"),
                @HystrixProperty(name = "circuitBreaker.requestVolumeThreshold", value = "10"),
                @HystrixProperty(name = "circuitBreaker.errorThresholdPercentage", value = "50")
        },
        threadPoolProperties = {
                @HystrixProperty(name = "coreSize", value = "1"),
                @HystrixProperty(name = "maxQueueSize", value = "10"),
                @HystrixProperty(name = "keepAliveTimeMinutes", value = "1000"),
                @HystrixProperty(name = "queueSizeRejectionThreshold", value = "8"),
                @HystrixProperty(name = "metrics.rollingStats.numBuckets", value = "12"),
                @HystrixProperty(name = "metrics.rollingStats.timeInMilliseconds", value = "1500")
    },ignoreExceptions = CommonServiceException.class)
    @RequestMapping(value = "",method = RequestMethod.GET)
    public BaseResponseVO describeCinemas(BasePageVO basePageVO) throws CommonServiceException {

        IPage<DescribeCinemasRespVO> describeCinemasRespVOIPage = cinemaServiceAPI.describeCinemas(basePageVO.getNowPage(), basePageVO.getPageSize());

        if(basePageVO.getNowPage()>10000){
            //throw new CommonServiceException(400,"nowPage太大了，不支持此处理");
            try {
                Thread.sleep(2000);
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
        }

        // TODO 调用封装的分页返回方法

        return BaseResponseVO.success();
    }

　　对nowPage值大于10000时，线程休眠2秒，而配置的超时时间timeoutInMilliseconds为1秒 。从而触发熔断，调用fallbackMethod方法。

fallbackMethod方法如下，该方法的参数和返回值要与describeCinemas保持一致。

    public BaseResponseVO fallbackMethod(BasePageVO basePageVO) throws CommonServiceException{

        // 返回一定是成功，或者业务处理失败
        Map<String,Object> result = Maps.newHashMap();
        result.put("code", 500);
        result.put("message","请求处理降级返回");
        return BaseResponseVO.success(result);
    }

　　

5、调用请求

当nowPage小于等于10000时，返回成功

 当nowPage大于10000时，触发熔断

二、Hystrix的Dashboard使用

1、打开http://localhost:8301/hystrix

 添加监控http://localhost:8301/actuator/hystrix.stream 

2、监控图

3、监控图数字含义

 Hystrix很少作为监控使用，它一般只有2分钟左右的状态，不能查历史状态，比较难找原因。适合双十一，比如每分钟都要监控到。