第四篇文章断路器讲述了如何使用断路器，并简单的介绍了下Hystrix Dashboard组件，
这篇文章更加详细的介绍Hystrix Dashboard。
在微服务架构中为例保证程序的可用性，防止程序出错导致网络阻塞，出现了断路器模型。断路器的状况反应了一个程序
的可用性和健壮性，它是一个重要指标。Hystrix Dashboard是作为断路器状态的一个组件，提供了数据监控和友好的图形
化界面。
本篇范例工程由上一篇（SpringCloud入门实战之十）源码的工程改造而来
第一部分：改造eureka-server工程
重新定义application.yml配置文件内容：
server:
port: 8761
eureka:
instance:
hostname: localhost
client:
registerWithEureka: false
fetchRegistry: false
serviceUrl:
defaultZone: http://${eureka.instance.hostname}:${server.port}/eureka/
spring:
application:
name: eurka-server第二部分：重新创建service-hi工程
删除service-hi工程重新创建它，目的是熟悉一下STS开发工具应该勾选那些选项自动生成我们需要的依赖：
勾选 Hystrix 生成依赖 spring-cloud-starter-netflix-hystrix
勾选 Hystrix Dashboard 生成依赖 spring-cloud-starter-netflix-hystrix-dashboard
勾选 Eureka Discovery 生成依赖 spring-cloud-starter-netflix-eureka-client
勾选 Actuator 生成依赖 spring-boot-starter-actuator
勾选 Web 生成依赖 spring-boot-starter-web
在程序的入口ServiceHiApplication类，加上@EnableHystrix注解开启断路器，这个是必须的，并且需要在程序中声
明断路点HystrixCommand；加上@EnableHystrixDashboard注解，开启HystrixDashboard
package com.contoso;
import com.netflix.hystrix.contrib.javanica.annotation.HystrixCommand;
import org.springframework.beans.factory.annotation.Value;
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;
import org.springframework.cloud.netflix.hystrix.EnableHystrix;
import org.springframework.cloud.netflix.hystrix.dashboard.EnableHystrixDashboard;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestParam;
import org.springframework.web.bind.annotation.RestController;
@SpringBootApplication
@EnableEurekaClient
@EnableDiscoveryClient
@RestController
@EnableHystrix
@EnableHystrixDashboard
@EnableCircuitBreaker
public class ServiceHiApplication {
/**
* 访问地址 http://localhost:8762/actuator/hystrix.stream
*
* @param args
*/
public static void main(String[] args) {
SpringApplication.run(ServiceHiApplication.class, args);
}
@Value("${server.port}")
String port;
@RequestMapping("/hi")
@HystrixCommand(fallbackMethod = "hiError")
public String message(@RequestParam(value = "name", defaultValue = "World") String name) {
return "Hello " + name + " ,this message is from port:" + port;
}
public String hiError(String name) {
return "Hello " + name + " ,sorry,error!";
}
}定义application.yml配置文件内容如下：
server:
port: 8762
spring:
application:
name: service-hi
eureka:
client:
serviceUrl:
defaultZone: http://localhost:8761/eureka/
management:
endpoints:
web:
exposure:
include: "*"
cors:
allowed-origins: "*"
allowed-methods: "*"启动工程： 依次运行eureka-server注册中心服务和service-hi服务提供者
Hystrix Dashboard图形展示
打开 http://localhost:8762/actuator/hystrix.stream 可以看到一些具体的数据：
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ping:
data: {"type":"HystrixCommand","name":"message","group":"ServiceHiApplication$$EnhancerBySpringCGLIB$$3fd63545","currentTime":1532281208812,"isCircuitBreakerOpen":false,"errorPercentage":0,"errorCount":0,"requestCount":0,"rollingCountBadRequests":0,"rollingCountCollapsedRequests":0,"rollingCountEmit":0,"rollingCountExceptionsThrown":0,"rollingCountFailure":0,"rollingCountFallbackEmit":0,"rollingCountFallbackFailure":0,"rollingCountFallbackMissing":0,"rollingCountFallbackRejection":0,"rollingCountFallbackSuccess":0,"rollingCountResponsesFromCache":0,"rollingCountSemaphoreRejected":0,"rollingCountShortCircuited":0,"rollingCountSuccess":0,"rollingCountThreadPoolRejected":0,"rollingCountTimeout":0,"currentConcurrentExecutionCount":0,"rollingMaxConcurrentExecutionCount":0,"latencyExecute_mean":0,"latencyExecute":{"0":0,"25":0,"50":0,"75":0,"90":0,"95":0,"99":0,"99.5":0,"100":0},"latencyTotal_mean":0,"latencyTotal":{"0":0,"25":0,"50":0,"75":0,"90":0,"95":0,"99":0,"99.5":0,"100":0},"propertyValue_circuitBreakerRequestVolumeThreshold":20,"propertyValue_circuitBreakerSleepWindowInMilliseconds":5000,"propertyValue_circuitBreakerErrorThresholdPercentage":50,"propertyValue_circuitBreakerForceOpen":false,"propertyValue_circuitBreakerForceClosed":false,"propertyValue_circuitBreakerEnabled":true,"propertyValue_executionIsolationStrategy":"THREAD","propertyValue_executionIsolationThreadTimeoutInMilliseconds":1000,"propertyValue_executionTimeoutInMilliseconds":1000,"propertyValue_executionIsolationThreadInterruptOnTimeout":true,"propertyValue_executionIsolationThreadPoolKeyOverride":null,"propertyValue_executionIsolationSemaphoreMaxConcurrentRequests":10,"propertyValue_fallbackIsolationSemaphoreMaxConcurrentRequests":10,"propertyValue_metricsRollingStatisticalWindowInMilliseconds":10000,"propertyValue_requestCacheEnabled":true,"propertyValue_requestLogEnabled":true,"reportingHosts":1,"threadPool":"ServiceHiApplication$$EnhancerBySpringCGLIB$$3fd63545"}
data: {"type":"HystrixThreadPool","name":"ServiceHiApplication$$EnhancerBySpringCGLIB$$3fd63545","currentTime":1532281208812,"currentActiveCount":0,"currentCompletedTaskCount":3,"currentCorePoolSize":10,"currentLargestPoolSize":3,"currentMaximumPoolSize":10,"currentPoolSize":3,"currentQueueSize":0,"currentTaskCount":3,"rollingCountThreadsExecuted":0,"rollingMaxActiveThreads":0,"rollingCountCommandRejections":0,"propertyValue_queueSizeRejectionThreshold":5,"propertyValue_metricsRollingStatisticalWindowInMilliseconds":10000,"reportingHosts":1}
本篇blog源码 spring-cloud-example11.zip