SpringCloud之Hystrix-Dashboard监控，以及踩的坑...

前言：

最近刚入职，公司使用了SpringCloud，之前有了解过SpringCloud，但是长时间不去搭建不去使用很容易就忘了，因此空闲时间重新复习一下SpringCloud。但是之前开的SpringCloud的版本可能有点低，公司现在用的 " Greenwich.RELEASE "的版本，SpringBoot使用了“ 2.1.x ”的版本，算是比较新了，因此在使用 Hystrix-Dashboard 的时候会有点坑，因此想把踩到的坑记录下来，让更多的人避开这个坑，废话不多说，开始了！

一、创建 Hystrix-Dashboard 监控服务：springcloud-hystrix-dashboard

工程pom依赖

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.1.7.RELEASE</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>
    <groupId>com.gxc.test</groupId>
    <artifactId>springcloud-hystrix-dashboard</artifactId>
    <version>1.0.0</version>

    <properties>
        <java.version>1.8</java.version>
    </properties>

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

    <dependencyManagement>
        <dependencies>
            <dependency>
                <groupId>org.springframework.cloud</groupId>
                <artifactId>spring-cloud-dependencies</artifactId>
                <version>Greenwich.RELEASE</version>
                <type>pom</type>
                <scope>import</scope>
            </dependency>
        </dependencies>
    </dependencyManagement>
</project>

yml配置文件

server:
  port: 10000
spring:
  application:
    name: springcloud-hystrix-dashboard

在启动类上添加注解 @EnableHystrixDashboard

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

启动！浏览器访问地址：http://localhost:10000/hystrix ，如下图：

二、创建Eureka注册中心：springcloud-eureka-server

有读者可能会问：不是说玩 Hystrix-Dashboard 吗？为啥还要用到Eureka？
答：请耐心往下看，这也是我为什么题目说的坑...

工程pom依赖

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.1.7.RELEASE</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>
    <groupId>com.gxc.test</groupId>
    <artifactId>springcloud-hystrix-dashboard</artifactId>
    <version>1.0.0</version>

    <properties>
        <java.version>1.8</java.version>
    </properties>

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

    <dependencyManagement>
        <dependencies>
            <dependency>
                <groupId>org.springframework.cloud</groupId>
                <artifactId>spring-cloud-dependencies</artifactId>
                <version>Greenwich.RELEASE</version>
                <type>pom</type>
                <scope>import</scope>
            </dependency>
        </dependencies>
    </dependencyManagement>
</project>

yml配置文件

server:
  port: 9000

spring:
  application:
    name: springcloud-eureka-server

eureka:
  client:
    register-with-eureka: false
    fetch-registry: false
    service-url:
      defaultZone: http://127.0.0.1:${server.port}/eureka

启动类添加注解：@EnableEurekaServer

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

启动！浏览器访问：http://localhost:9000/ ，如下图：

三、创建被监控服务：springcloud-user

工程pom依赖

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.1.7.RELEASE</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>
    <groupId>com.gxc.test</groupId>
    <artifactId>springcloud-user</artifactId>
    <version>1.0.0</version>
    <properties>
        <java.version>1.8</java.version>
    </properties>

    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-actuator</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-netflix-eureka-client</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-netflix-hystrix</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-openfeign</artifactId>
        </dependency>
    </dependencies>

    <dependencyManagement>
        <dependencies>
            <dependency>
                <groupId>org.springframework.cloud</groupId>
                <artifactId>spring-cloud-dependencies</artifactId>
                <version>Greenwich.RELEASE</version>
                <type>pom</type>
                <scope>import</scope>
            </dependency>
        </dependencies>
    </dependencyManagement>
</project>

yml配置文件

server:
  port: 10001

spring:
  application:
    name: springcloud-user

# 将服务注册到Eureka注册中心
eureka:
  client:
    service-url:
      defaultZone: http://127.0.0.1:9000/eureka
  instance:
    prefer-ip-address: true
    instance-id: ${spring.application.name}:${server.port}

feign:
  hystrix:
    enabled: true

启动类添加注解

//@EnableCircuitBreaker
//@EnableEurekaClient
//@EnableFeignClients
//@SpringBootApplication

// 以上四个注解可以用如下两个注解取代
@EnableFeignClients
@SpringCloudApplication
public class UserApplication {
    public static void main(String[] args) {
        SpringApplication.run(UserApplication.class, args);
    }
}

创建测试Controller类

@RestController
public class UserController {
    @GetMapping("/user")
    public Object getUser() {
        Map<String, Object> user = Maps.newHashMap();
        user.put("username","GongXincheng");
        user.put("age", 23);
        user.put("birthday", new Date());
        return user;
    }
}

启动！浏览器访问：http://localhost:10001/user，如下图：

四、测试 Hystrix-Dashboard 监控 user 服务

浏览器访问：http://localhost:10001/hystrix.stream ，出现了404错误
说明：第一个坑，在SpringBoot 2.0之前，只要添加了Actuator依赖，不会出现404错误的
解决404问题：创建一个配置类，并注册一个Servlet

@Configuration
public class ServletConfigBean {
    @Bean
    public ServletRegistrationBean hystrixMetricsStreamServlet() {
        ServletRegistrationBean regist = new ServletRegistrationBean();
        regist.setServlet(new HystrixMetricsStreamServlet());
        regist.setName("hystrixMetricsStreamServlet");
        regist.setLoadOnStartup(1);
        regist.addUrlMappings("/hystrix.stream");
        return regist;
    }
}

浏览器访问：http://localhost:10001/hystrix.stream ，如下图：
将第一步的链接：http://localhost:10001/hystrix.stream ，复制到 Hystrix-Dashboard页面中
Hystrix-Dashboard会一直在 loading... 中，这就是第二个坑...
解决办法：

1：创建另一个服务（例如：springcloud-order）
2：将新的服务（order）注册到Eureka
3：在user服务写一个新的Api接口，通过 Feign 访问新服务（order）的Api接口
4：注意：经过本人测试通过RestTemplate的方式调用，仍然没有效果。
5：当通过Feign调用一次新服务（order）后，hystrix.stream 正常，效果如下：

Controller层代码

@RestController
public class UserController {

    private static final String ORDER_SERVER_URL = "http://springcloud-order";

    @Resource private OrderFeign orderFeign;
    @Resource private RestTemplate restTemplate;

    @GetMapping("/user")
    public Object getUser() {
        Map<String, Object> user = Maps.newHashMap();
        user.put("username","GongXincheng");
        user.put("age", 23);
        user.put("birthday", new Date());
        return user;
    }

    @GetMapping("/feign/order")
    public Object feignGetOrder() {
        return orderFeign.getOrder();
    }

    @GetMapping("/rest/order")
    public Object restGetOrder() {
        return restTemplate.getForObject(ORDER_SERVER_URL + "/order", Object.class);
    }
}

8：user服务和oder服务目录结构和相关代码

五：代码链接

https://gitee.com/gxc6/gxc-springcloud-study

如果有什么错误的地方，欢迎大家帮忙指正！感谢！

我透... 写完这个已经凌晨3点了... 溜了溜了...