Springcloud基础知识（7）- Spring Cloud Hystrix (二) | Hystrix 全局/解耦降级、服务熔断、故障监控
作者：互联网
1. Hystrix 全局降级
在 “Springcloud基础知识（6）- Spring Cloud Hystrix (一) | 服务降级” 里的 SpringcloudDemo03 项目，ServiceProviderHystrix 子模块实现了服务端服务降级， ConsumerFeign 子模块实现了客户端服务降级。
服务端和客户端的服务降级，都是给每个业务方法配置一个降级方法，如果需要针对所有业务方法都配置降级方法，代码将非常冗余。
为了解决代码冗余问题，Hystrix 提供了全局降级（Fallback）方法。
本文将在 ConsumerFeign 子模块基础上，修改代码和配置，演示实现全局降级。
1) 修改 src/main/java/com/example/controller/ConsumerController.java 文件
1 package com.example.controller;
2
3 import java.util.List;
4
5 import org.springframework.beans.factory.annotation.Autowired;
6 import org.springframework.web.bind.annotation.PathVariable;
7 import org.springframework.web.bind.annotation.RequestMapping;
8 import org.springframework.web.bind.annotation.RestController;
9 import com.netflix.hystrix.contrib.javanica.annotation.HystrixCommand;
10 import com.netflix.hystrix.contrib.javanica.annotation.DefaultProperties;
11
12 import com.example.entity.Employee;
13 import com.example.service.EmployeeFeignService;
14 import com.example.service.EmployeeHystrixService;
15
16 @RestController
17 @RequestMapping(value = "/consumer")
18 @DefaultProperties(defaultFallback = "defaultFallbackHandler") // 配置全局降级（Fallback）方法
19 public class ConsumerController {
20 @Autowired
21 private EmployeeFeignService employeeFeignService;
22 @Autowired
23 private EmployeeHystrixService employeeHystrixService;
24
25 @RequestMapping(value = "/employee/get/{id}")
26 public Employee get(@PathVariable("id") Integer id) {
27 return employeeFeignService.get(id);
28 }
29
30 @RequestMapping(value = "/employee/list")
31 public List<Employee> list() {
32 return employeeFeignService.list();
33 }
34
35 @RequestMapping(value = "/employee/hystrix/ok/{id}")
36 //@HystrixCommand(fallbackMethod = "timeoutHandler")
37 @HystrixCommand // 不带参数，会自动匹配默认全局降级（Fallback）方法
38 public String employeeInfo_Ok(@PathVariable("id") Integer id) {
39 return employeeHystrixService.employeeInfo_Ok(id);
40 }
41
42 @RequestMapping(value = "/employee/hystrix/timeout/{id}")
43 @HystrixCommand
44 public String employeeInfo_Timeout(@PathVariable("id") Integer id) {
45 return employeeHystrixService.employeeInfo_Timeout(id);
46 }
47
48 // employeeInfo_Ok() 的 fallback 方法
49 public String timeoutHandler(@PathVariable("id") Integer id) {
50 return "Client: system in busy, please try later!";
51 }
52
53 // 定义全局降级（Fallback）方法，不带参数
54 public String defaultFallbackHandler() {
55 return "Client - default: system in busy, please try later!";
56 }
57 }
使用全局降级（Fallback）方法的注意点：
(1) 全局降级（Fallback）方法必须与其对应的业务方法在同一个类中，否则无法生效；
(2) 全局降级（Fallback）方法不带参数；
(3) 全局降级（Fallback）方法的优先级较低，业务方法没有指定其降级方法时，才会触发全局 FallBack 方法。
2) 运行
依次启动 server-7001、server-7002、server-7003，启动的间隔 5 ~ 10 秒，都启动后等待 10 秒左右。
启动 server-8004，访问 http://localhost:8004/employee/hystrix/ok/1，4 秒后显示结果如下：
EmployeeServiceImpl -> employeeInfo_Ok(): thread = hystrix-EmployeeServiceImpl-1, id = 1, timeoutValue = 4, port: 8004
启动 ConsumerFeign 模块，访问 http://localhost/consumer/employee/hystrix/ok/1，3 秒后显示结果如下：
Client - default: system in busy, please try later!
2. Hystrix 解耦降级逻辑
不管是业务方法指定的降级方法还是全局降级方法，它们都必须和业务方法在同一个类中才能生效，业务逻辑与降级逻辑耦合度极高。
本文将在 ConsumerFeign 子模块基础上，修改代码和配置，演示对业务逻辑与降级逻辑进行解耦。
1) 创建 src/main/java/com/example/service/EmployeeHystrixFallbackService.java 文件
1 package com.example.service;
2
3 import org.springframework.stereotype.Component;
4
5 @Component
6 public class EmployeeHystrixFallbackService implements EmployeeHystrixService {
7
8 @Override
9 public String employeeInfo_Ok(Integer id) {
10 return "Client - standalone (OK): system in busy, please try later!";
11 }
12
13 @Override
14 public String employeeInfo_Timeout(Integer id) {
15 return "Client - standalone (Timeout): system in busy, please try later!";
16 }
17
18 }
2) 修改 src/main/java/com/example/service/EmployeeHystrixService.java 文件
1 package com.example.service;
2
3 import org.springframework.stereotype.Service;
4 import org.springframework.cloud.openfeign.FeignClient;
5 import org.springframework.web.bind.annotation.PathVariable;
6 import org.springframework.web.bind.annotation.RequestMapping;
7
8 @Service
9 @FeignClient(value = "EMPLOYEE-SERVICE-PROVIDER-HYSTRIX", fallback = EmployeeHystrixFallbackService.class)
10 public interface EmployeeHystrixService {
11 @RequestMapping(value = "/employee/hystrix/ok/{id}")
12 public String employeeInfo_Ok(@PathVariable("id") Integer id);
13
14 @RequestMapping(value = "/employee/hystrix/timeout/{id}")
15 public String employeeInfo_Timeout(@PathVariable("id") Integer id);
16 }
3) 修改 src/main/java/com/example/controller/ConsumerController.java 文件
1 package com.example.controller;
2
3 import java.util.List;
4
5 import org.springframework.beans.factory.annotation.Autowired;
6 import org.springframework.web.bind.annotation.PathVariable;
7 import org.springframework.web.bind.annotation.RequestMapping;
8 import org.springframework.web.bind.annotation.RestController;
9
10 import com.example.entity.Employee;
11 import com.example.service.EmployeeFeignService;
12 import com.example.service.EmployeeHystrixService;
13
14 @RestController
15 @RequestMapping(value = "/consumer")
16 public class ConsumerController {
17 @Autowired
18 private EmployeeFeignService employeeFeignService;
19 @Autowired
20 private EmployeeHystrixService employeeHystrixService;
21
22 @RequestMapping(value = "/employee/get/{id}")
23 public Employee get(@PathVariable("id") Integer id) {
24 return employeeFeignService.get(id);
25 }
26
27 @RequestMapping(value = "/employee/list")
28 public List<Employee> list() {
29 return employeeFeignService.list();
30 }
31
32 @RequestMapping(value = "/employee/hystrix/ok/{id}")
33 public String employeeInfo_Ok(@PathVariable("id") Integer id) {
34 return employeeHystrixService.employeeInfo_Ok(id);
35 }
36
37 @RequestMapping(value = "/employee/hystrix/timeout/{id}")
38 public String employeeInfo_Timeout(@PathVariable("id") Integer id) {
39 return employeeHystrixService.employeeInfo_Timeout(id);
40 }
41
42 }
4) 运行
重启 server-8004，访问 http://localhost:8004/employee/hystrix/ok/1，4 秒后显示结果如下：
EmployeeServiceImpl -> employeeInfo_Ok(): thread = hystrix-EmployeeServiceImpl-1, id = 1, timeoutValue = 4, port: 8004
启动 ConsumerFeign 模块，访问 http://localhost/consumer/employee/hystrix/ok/1，3 秒后显示结果如下：
Client - standalone (OK): system in busy, please try later!
3. Hystrix 服务熔断
熔断机制是为了应对雪崩效应而出现的一种微服务链路保护机制。
当微服务系统中的某个微服务不可用或响应时间太长时，为了保护系统的整体可用性，熔断器会暂时切断请求对该服务的调用，并快速返回一个友好的错误响应。这种熔断状态不是永久的，在经历了一定的时间后，熔断器会再次检测该微服务是否恢复正常，若服务恢复正常则恢复其调用链路。
在熔断机制中涉及了三种熔断状态：
(1) 熔断关闭状态（Closed）：当务访问正常时，熔断器处于关闭状态，服务调用方可以正常地对服务进行调用；
(2) 熔断开启状态（Open）：默认情况下，在固定时间内接口调用出错比率达到一个阈值（例如 50%），熔断器会进入熔断开启状态。进入熔断状态后，后续对该服务的调用都会被切断，熔断器会执行本地的降级（FallBack）方法；
(3) 半熔断状态（Half-Open）：在熔断开启一段时间之后，熔断器会进入半熔断状态。在半熔断状态下，熔断器会尝试恢复服务调用方对服务的调用，允许部分请求调用该服务，并监控其调用成功率。如果成功率达到预期，则说明服务已恢复正常，熔断器进入关闭状态；如果成功率仍旧很低，则重新进入熔断开启状态；
Hystrix 实现服务熔断的步骤如下：
(1) 当服务的调用出错率达到或超过 Hystix 规定的比率（默认为 50%）后，熔断器进入熔断开启状态；
(2) 熔断器进入熔断开启状态后，Hystrix 会启动一个休眠时间窗，在这个时间窗内，该服务的降级逻辑会临时充当业务主逻辑，而原来的业务主逻辑不可用；
(3) 当有请求再次调用该服务时，会直接调用降级逻辑快速地返回失败响应，以避免系统雪崩；
(4) 当休眠时间窗到期后，Hystrix 会进入半熔断转态，允许部分请求对服务原来的主业务逻辑进行调用，并监控其调用成功率；
(5) 如果调用成功率达到预期，则说明服务已恢复正常，Hystrix 进入熔断关闭状态，服务原来的主业务逻辑恢复；否则 Hystrix 重新进入熔断开启状态，休眠时间窗口重新计时，继续重复第 2 ~ 5 步；
本文将在 ServiceProviderHystrix 子模块基础上，修改代码和配置，演示实现熔断机制。
1) 修改 src/main/java/com/example/service/EmployeeService.java 文件
1 package com.example.service;
2
3 public interface EmployeeService {
4
5 // Hystrix 熔断器，显示 Ok
6 public String employeeInfo_Ok(Integer id);
7
8 // Hystrix 熔断器，显示 Timeout
9 public String employeeInfo_Timeout(Integer id);
10
11 // Hystrix 熔断机制
12 public String employeeInfo_CircuitBreaker(Integer id);
13
14 }
2) 修改 src/main/java/com/example/service/EmployeeServiceImpl.java 文件
1 package com.example.service;
2
3 import java.util.concurrent.TimeUnit;
4 import org.springframework.stereotype.Service;
5 import com.netflix.hystrix.contrib.javanica.annotation.HystrixCommand;
6 import com.netflix.hystrix.contrib.javanica.annotation.HystrixProperty;
7
8 @Service("employeeService")
9 public class EmployeeServiceImpl implements EmployeeService {
10
11 @Override
12 @HystrixCommand(fallbackMethod = "timeoutHandler",
13 commandProperties = {
14 @HystrixProperty(name = "execution.isolation.thread.timeoutInMilliseconds",
15 value = "5000")
16 })
17 public String employeeInfo_Ok(Integer id) {
18
19 int timeoutValue = 4;
20 try {
21 TimeUnit.SECONDS.sleep(timeoutValue);
22 } catch (InterruptedException e) {
23 e.printStackTrace();
24 }
25
26 return "EmployeeServiceImpl -> employeeInfo_Ok(): thread = " + Thread.currentThread().getName() + ", id = " + id + ", timeoutValue = " + timeoutValue;
27 }
28
29 @Override
30 @HystrixCommand(fallbackMethod = "timeoutHandler",
31 commandProperties = {
32 @HystrixProperty(name = "execution.isolation.thread.timeoutInMilliseconds",
33 value = "5000")
34 })
35 public String employeeInfo_Timeout(Integer id) {
36
37 int timeoutValue = 6;
38 try {
39 TimeUnit.SECONDS.sleep(timeoutValue);
40 } catch (InterruptedException e) {
41 e.printStackTrace();
42 }
43
44 return "EmployeeServiceImpl -> employeeInfo_Timeout(): thread = " + Thread.currentThread().getName() + ", id = " + id + ", timeoutValue = " + timeoutValue;
45 }
46
47 public String timeoutHandler(Integer id) {
48 return "Server: system in busy, please try later! thread = " + Thread.currentThread().getName() + ", id = " + id;
49 }
50
51 @Override
52 @HystrixCommand(
53 fallbackMethod = "circuitBreakerHandler",
54 commandProperties = {
55 @HystrixProperty(name = "circuitBreaker.enabled", value = "true"), // 是否开启熔断器
56 @HystrixProperty(name = "metrics.rollingStats.timeInMilliseconds",value = "1000"), // 统计时间窗
57 @HystrixProperty(name = "circuitBreaker.requestVolumeThreshold", value = "5"), // 统计时间窗内请求次数
58 @HystrixProperty(name = "circuitBreaker.sleepWindowInMilliseconds", value = "5000"), // 休眠时间窗口期
59 @HystrixProperty(name = "circuitBreaker.errorThresholdPercentage", value = "60"), // 在统计时间窗口期以内，请求失败率达到 60% 时进入熔断状态
60 }
61 )
62 public String employeeInfo_CircuitBreaker(Integer id) {
63 if (id < 0) {
64 // 当传入的 id 为负数时，抛出异常，调用降级方法
65 throw new RuntimeException("Server (Circuit Breaker): error, invalid id");
66 }
67
68 return "Server (Circuit Breaker): success, id = " + id;
69 }
70
71 // employeeInfo_CircuitBreaker 的降级方法
72 public String circuitBreakerHandler(Integer id) {
73 return "Server (Circuit Breaker): system in busy, please try later! id = " + id;
74 }
75 }
与 Hystrix 熔断机制相关的 4 个参数的含义如下表。
| 参数 | 描述 |
| metrics.rollingStats.timeInMilliseconds | 统计时间窗。 |
| circuitBreaker.sleepWindowInMilliseconds | 休眠时间窗，熔断开启状态持续一段时间后，熔断器会自动进入半熔断状态，这段时间就被称为休眠窗口期。 |
| circuitBreaker.requestVolumeThreshold | 请求总数阀值。在统计时间窗内，请求总数必须到达一定的数量级，Hystrix 才可能会将熔断器打开进入熔断开启转态，而这个请求数量级就是 请求总数阀值。Hystrix 请求总数阈值默认为 20，这就意味着在统计时间窗内，如果服务调用次数不足 20 次，即使所有的请求都调用出错，熔断器也不会打开。 |
| circuitBreaker.errorThresholdPercentage | 错误百分比阈值。当请求总数在统计时间窗内超过了请求总数阀值，且请求调用出错率超过一定的比例，熔断器才会打开进入熔断开启转态，而这个比例就是错误百分比阈值。错误百分比阈值设置为 50，就表示错误百分比为 50%，如果服务发生了 30 次调用，其中有 15 次发生了错误，即超过了 50% 的错误百分比，这时候将熔断器就会打开。 |
3) 修改 src/main/java/com/example/controller/EmployeeServiceImpl.java 文件
1 package com.example.controller;
2
3 import lombok.extern.slf4j.Slf4j;
4 import org.springframework.beans.factory.annotation.Autowired;
5 import org.springframework.beans.factory.annotation.Value;
6 import org.springframework.web.bind.annotation.RestController;
7 import org.springframework.web.bind.annotation.RequestMapping;
8 import org.springframework.web.bind.annotation.PathVariable;
9
10 import com.example.service.EmployeeService;
11
12 @RestController
13 @Slf4j
14 @RequestMapping(value = "/employee")
15 public class EmployeeController {
16 @Autowired
17 private EmployeeService employeeService;
18 @Value("${server.port}")
19 private String serverPort;
20
21 @RequestMapping(value = "/hystrix/ok/{id}")
22 public String employeeInfo_Ok(@PathVariable("id") Integer id) {
23
24 String result = employeeService.employeeInfo_Ok(id);
25 log.info("port：" + serverPort + ", result:" + result);
26 return result + ", port: " + serverPort;
27
28 }
29
30 // Hystrix 服务超时降级
31 @RequestMapping(value = "/hystrix/timeout/{id}")
32 public String employeeInfo_Timeout(@PathVariable("id") Integer id) {
33
34 String result = employeeService.employeeInfo_Timeout(id);
35 log.info("port：" + serverPort + ", result:" + result);
36 return result + ", port: " + serverPort;
37
38 }
39
40 // Hystrix 服务熔断
41 @RequestMapping(value = "/hystrix/circuit/{id}")
42 public String employeeInfo_CircuitBreaker(@PathVariable("id") Integer id) {
43
44 String result = employeeService.employeeInfo_CircuitBreaker(id);
45 log.info("port：" + serverPort + ", result:" + result);
46 return result + ", port: " + serverPort;
47
48 }
49
50 }
4) 运行
启动 server-7001、server-7002、server-7003，启动的间隔 5 ~ 10 秒，都启动后等待 10 秒左右。
启动 ServiceProviderHystrix 模块，访问 http://localhost:8004/employee/hystrix/circuit/1，显示结果如下：
Server (Circuit Breaker): success, id = 1, port: 8004
再访问 http://localhost:8004/employee/hystrix/circuit/-1 ，连续快速刷新页面 10 次（次数大于请求总数阀值，使调用出错率大于错误百分比阀值），显示结果如下：
Server (Circuit Breaker): system in busy, please try later! id = -1, port: 8004
在 5 秒内访问 http://localhost:8004/employee/hystrix/circuit/2 ，显示结果如下：
Server (Circuit Breaker): system in busy, please try later! id = 2, port: 8004
注：在熔断开启状态下，即使传入的参数已经是正数，调用的依然降级逻辑。
继续连续访问 http://localhost:8004/employee/hystrix/circuit/2，显示结果如下：
Server (Circuit Breaker): success, id = 2, port: 8004
注：当服务调用正确率上升到一定的比率后，Hystrix 进入熔断关闭状态。
4. Hystrix 故障监控
Hystrix 还提供了准实时的调用监控（Hystrix Dashboard）功能，Hystrix 会持续地记录所有通过 Hystrix 发起的请求的执行信息，并以统计报表的形式展示给用户，包括每秒执行请求的数量、成功请求的数量和失败请求的数量等。
本文将在上文修改过的 SringcloudDemo03 项目基础上，添加一个 HystrixDashboard 子模块，来监控 ServiceProviderHystrix 模块的运行情况。
SpringcloudDemo03 的 Spring Boot 版本是 2.3.12.RELEASE。
1) 创建 HystrixDashboard 模块
选择左上的项目列表中的 SpringcloudDemo03，点击鼠标右键，选择 New -> Module 进入 New Module 页面：
Maven -> Project SDK: 1.8 -> Check "Create from archtype" -> select "org.apache.maven.archtypes:maven-archtype-quickstart" -> Next
Name: HystrixDashboard
GroupId: com.example
ArtifactId: HystrixDashboard
-> Finish
注：模块 HystrixDashboard 创建后，Maven 命令会自动修改主项目 SpringcloudDemo03 的 pom.xml，添加如下内容：
<modules>
...
<module>HystrixDashboard</module>
</modules>
2) 修改 pom.xml 内容如下
1 <?xml version="1.0" encoding="UTF-8"?> 2 <project xmlns="http://maven.apache.org/POM/4.0.0" 3 xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" 4 xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 5 http://maven.apache.org/xsd/maven-4.0.0.xsd"> 6 <parent> 7 <artifactId>SpringcloudDemo03</artifactId> 8 <groupId>com.example</groupId> 9 <version>1.0-SNAPSHOT</version> 10 </parent> 11 <modelVersion>4.0.0</modelVersion> 12 13 <artifactId>HystrixDashboard</artifactId> 14 15 <name>HystrixDashboard</name> 16 <!-- FIXME change it to the project's website --> 17 <url>http://www.example.com</url> 18 19 <properties> 20 <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding> 21 <maven.compiler.source>1.8</maven.compiler.source> 22 <maven.compiler.target>1.8</maven.compiler.target> 23 </properties> 24 25 <dependencies> 26 <dependency> 27 <groupId>junit</groupId> 28 <artifactId>junit</artifactId> 29 <version>4.12</version> 30 <scope>test</scope> 31 </dependency> 32 <dependency> 33 <groupId>org.springframework.boot</groupId> 34 <artifactId>spring-boot-starter</artifactId> 35 </dependency> 36 <dependency> 37 <groupId>org.springframework.boot</groupId> 38 <artifactId>spring-boot-starter-test</artifactId> 39 <scope>test</scope> 40 </dependency> 41 <!-- hystrix-dashboard 监控的依赖 --> 42 <dependency> 43 <groupId>org.springframework.cloud</groupId> 44 <artifactId>spring-cloud-starter-netflix-hystrix-dashboard</artifactId> 45 </dependency> 46 <!-- 添加 Spring Boot 的监控模块 --> 47 <dependency> 48 <groupId>org.springframework.boot</groupId> 49 <artifactId>spring-boot-starter-actuator</artifactId> 50 </dependency> 51 </dependencies> 52 53 <build> 54 <plugins> 55 <plugin> 56 <groupId>org.springframework.boot</groupId> 57 <artifactId>spring-boot-maven-plugin</artifactId> 58 <configuration> 59 <mainClass>com.example.App</mainClass> 60 <layout>JAR</layout> 61 </configuration> 62 <executions> 63 <execution> 64 <goals> 65 <goal>repackage</goal> 66 </goals> 67 </execution> 68 </executions> 69 </plugin> 70 </plugins> 71 </build> 72 </project>
3) 创建 src/main/resources/application.yml 文件
1 server: 2 port: 9002 # 端口号, http://localhost:9002/hystrix 熔断器监控页面 3 4 hystrix: 5 dashboard: 6 proxy-stream-allow-list: 7 - "localhost" # http://localhost:8004/actuator/hystrix.stream 监控地址
4) 修改 src/main/java/com/example/App.java 文件
1 package com.example;
2
3 import org.springframework.boot.SpringApplication;
4 import org.springframework.boot.autoconfigure.SpringBootApplication;
5 import org.springframework.cloud.netflix.hystrix.dashboard.EnableHystrixDashboard;
6
7 @SpringBootApplication
8 @EnableHystrixDashboard
9 public class App {
10 public static void main(String[] args) {
11 SpringApplication.run(App.class, args);
12 }
13 }
5) 创建 src/main/java/com/example/config/HystrixDashboardConfig.java 文件
1 package com.example.config;
2
3 import com.netflix.hystrix.contrib.metrics.eventstream.HystrixMetricsStreamServlet;
4 import org.springframework.boot.web.servlet.ServletRegistrationBean;
5 import org.springframework.context.annotation.Bean;
6 import org.springframework.context.annotation.Configuration;
7
8 @Configuration
9 public class HystrixDashboardConfig {
10
11 @Bean
12 public ServletRegistrationBean getServlet() {
13 HystrixMetricsStreamServlet streamServlet = new HystrixMetricsStreamServlet();
14 ServletRegistrationBean registrationBean = new ServletRegistrationBean(streamServlet);
15 registrationBean.setLoadOnStartup(1);
16 registrationBean.addUrlMappings("/actuator/hystrix.stream"); // 访问路径
17 registrationBean.setName("hystrix.stream");
18 return registrationBean;
19 }
20 }
6) 运行
启动 server-7001、server-7002、server-7003。
启动 ServiceProviderHystrix 模块，访问 http://localhost:8004/actuator/，页面显示如下：
1 {"_links":{"self":{"href":"http://localhost:8004/actuator","templated":false},
2 "archaius":{"href":"http://localhost:8004/actuator/archaius","templated":false},
3 "beans":{"href":"http://localhost:8004/actuator/beans","templated":false},
4 "caches-cache":{"href":"http://localhost:8004/actuator/caches/{cache}",
5 "templated":true},"caches":{"href":"http://localhost:8004/actuator/caches",
6 "templated":false},
7 "health-path":{"href":"http://localhost:8004/actuator/health/{*path}",
8 "templated":true},"health":{"href":"http://localhost:8004/actuator/health",
9 "templated":false},"info":{"href":"http://localhost:8004/actuator/info",
10 "templated":false},"conditions":{"href":"http://localhost:8004/actuator/conditions","templated":false},
11 "configprops":{"href":"http://localhost:8004/actuator/configprops","templated":false},
12 "env":{"href":"http://localhost:8004/actuator/env","templated":false},
13 "env-toMatch":{"href":"http://localhost:8004/actuator/env/{toMatch}","templated":true},
14 "loggers":{"href":"http://localhost:8004/actuator/loggers","templated":false},
15 "loggers-name":{"href":"http://localhost:8004/actuator/loggers/{name}","templated":true},
16 "heapdump":{"href":"http://localhost:8004/actuator/heapdump","templated":false},
17 "threaddump":{"href":"http://localhost:8004/actuator/threaddump","templated":false},
18 "metrics-requiredMetricName":{"href":"http://localhost:8004/actuator/metrics/{requiredMetricName}","templated":true},
19 "metrics":{"href":"http://localhost:8004/actuator/metrics","templated":false},
20 "scheduledtasks":{"href":"http://localhost:8004/actuator/scheduledtasks","templated":false},
21 "mappings":{"href":"http://localhost:8004/actuator/mappings","templated":false},
22 "refresh":{"href":"http://localhost:8004/actuator/refresh","templated":false},
23 "features":{"href":"http://localhost:8004/actuator/features","templated":false},
24 "service-registry":{"href":"http://localhost:8004/actuator/service-registry","templated":false},
25 "hystrix.stream":{"href":"http://localhost:8004/actuator/hystrix.stream","templated":false}}}
启动 HystrixDashboard 模块，访问 http://localhost:9002/hystrix，页面提示输入监控地址：
输入 http://localhost:8004/actuator/hystrix.stream ，点击 “Monitor Stream” 按钮。
多次访问 http://localhost:8004/employee/hystrix/circuit/1 和 http://localhost:8004/employee/hystrix/circuit/-2 ， 再查看 http://localhost:9002/hystrix 页面上统计。
标签：http,hystrix,Hystrix,Springcloud,Spring,8004,import,id,localhost 来源： https://www.cnblogs.com/tkuang/p/16422160.html