手把手教你玩转SpringCloud

微服务之消息总线（Spring Cloud Bus）

"Hello SpringBoot, Hello SpringClould"

Posted by 墨城烟柳（Mcyl） on January 15, 2019

“Hello everyone! ”

消息总线（Spring Cloud Bus）简介

spring cloud bus整合java的事件处理机制和消息中间件消息的发送和接受，主要由发送端、 接收端和事件组成。针对不同的业务需求，可以设置不同的事件，发送端发送事件，接收端 接受相应的事件，并进行相应的处理。

第一步：创建条件

首先安装rabbitmq，然后创建一个maven主工程.

第二步：创建eureka-server工程：

右键工程->创建module->选择spring initialir->cloud discovery->eureka server,然后一直下一步就行了。

创建完成后：

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<?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 http://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>2.1.1.RELEASE</version>
		<relativePath/> <!-- lookup parent from repository -->
	</parent>
	<groupId>com.test</groupId>
	<artifactId>eureka-server</artifactId>
	<version>0.0.1-SNAPSHOT</version>
	<name>eureka-server</name>
	<description>Demo project for Spring Boot</description>

	<properties>
		<java.version>1.8</java.version>
		<spring-cloud.version>Greenwich.RC2</spring-cloud.version>
	</properties>

	<dependencies>
		<dependency>
			<groupId>org.springframework.cloud</groupId>
			<artifactId>spring-cloud-starter-netflix-eureka-server</artifactId>
		</dependency>

		<dependency>
			<groupId>org.springframework.boot</groupId>
			<artifactId>spring-boot-starter-test</artifactId>
			<scope>test</scope>
		</dependency>
	</dependencies>

	<dependencyManagement>
		<dependencies>
			<dependency>
				<groupId>org.springframework.cloud</groupId>
				<artifactId>spring-cloud-dependencies</artifactId>
				<version>${spring-cloud.version}</version>
				<type>pom</type>
				<scope>import</scope>
			</dependency>
		</dependencies>
	</dependencyManagement>

	<build>
		<plugins>
			<plugin>
				<groupId>org.springframework.boot</groupId>
				<artifactId>spring-boot-maven-plugin</artifactId>
			</plugin>
		</plugins>
	</build>

	<repositories>
		<repository>
			<id>spring-milestones</id>
			<name>Spring Milestones</name>
			<url>https://repo.spring.io/milestone</url>
		</repository>
	</repositories>

</project>

配置appication.yml文件：

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server:
  port: 9871
eureka:
  instance:
	hostname: localhost
  client:
	register-with-eureka: false
	fetch-registry: false
  service-url:
	defaultZone: http://${eureka.instance.hostname}:${server.port}/eureka/

第三步 修改主程序

添加注解@EnableEurekaServer

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import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.netflix.eureka.server.EnableEurekaServer;

@SpringBootApplication
@EnableEurekaServer
public class EurekaServerApplication {

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

}

第四步：创建config-server工程：

右键工程->创建module->选择spring initialir->cloud discovery->eureka client,web->web,cloud config->server,然后一直下一步就行了。

创建完成后：

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<?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 http://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>2.1.1.RELEASE</version>
		<relativePath/> <!-- lookup parent from repository -->
	</parent>
	<groupId>com.test</groupId>
	<artifactId>config-server</artifactId>
	<version>0.0.1-SNAPSHOT</version>
	<name>config-server</name>
	<description>Demo project for Spring Boot</description>

	<properties>
		<java.version>1.8</java.version>
		<spring-cloud.version>Greenwich.RC2</spring-cloud.version>
	</properties>

	<dependencies>
		<dependency>
			<groupId>org.springframework.boot</groupId>
			<artifactId>spring-boot-starter-web</artifactId>
		</dependency>
		<dependency>
			<groupId>org.springframework.cloud</groupId>
			<artifactId>spring-cloud-config-server</artifactId>
		</dependency>
		<dependency>
			<groupId>org.springframework.cloud</groupId>
			<artifactId>spring-cloud-starter-netflix-eureka-client</artifactId>
		</dependency>

		<dependency>
			<groupId>org.springframework.boot</groupId>
			<artifactId>spring-boot-starter-test</artifactId>
			<scope>test</scope>
		</dependency>
	</dependencies>

	<dependencyManagement>
		<dependencies>
			<dependency>
				<groupId>org.springframework.cloud</groupId>
				<artifactId>spring-cloud-dependencies</artifactId>
				<version>${spring-cloud.version}</version>
				<type>pom</type>
				<scope>import</scope>
			</dependency>
		</dependencies>
	</dependencyManagement>

	<build>
		<plugins>
			<plugin>
				<groupId>org.springframework.boot</groupId>
				<artifactId>spring-boot-maven-plugin</artifactId>
			</plugin>
		</plugins>
	</build>

	<repositories>
		<repository>
			<id>spring-milestones</id>
			<name>Spring Milestones</name>
			<url>https://repo.spring.io/milestone</url>
		</repository>
	</repositories>

</project>

配置appication.yml文件：

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server:
  port: 8888
spring:
  application:
	name: config-server
  cloud:
	config:
	  server:
		git:
		  uri: https://github.com/mochengyanliu/SpringCloudConfig
		  search-paths: dev
		  username:
		  password:
	  label: master
eureka:
  client:
	service-url:
	  defaultZone: http://localhost:9871/eureka/

第五步 配置主程序

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import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.config.server.EnableConfigServer;
import org.springframework.cloud.netflix.eureka.EnableEurekaClient;

@SpringBootApplication
@EnableEurekaClient
@EnableConfigServer
public class ConfigServerApplication {

	public static void main(String[] args) {
		SpringApplication.run(ConfigServerApplication.class, args);
	}

}

第六步：创建config-client工程：

右键工程->创建module->选择spring initialir->cloud discovery->eureka client,web->web,cloud config->client,intgeration->tabbitmq,ops->actuator,然后一直下一步就行了。

创建完成后：

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<?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 http://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>2.1.2.RELEASE</version>
		<relativePath/> <!-- lookup parent from repository -->
	</parent>
	<groupId>com.test</groupId>
	<artifactId>config-client</artifactId>
	<version>0.0.1-SNAPSHOT</version>
	<name>config-client</name>
	<description>Demo project for Spring Boot</description>

	<properties>
		<java.version>1.8</java.version>
		<spring-cloud.version>Greenwich.RC2</spring-cloud.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-amqp</artifactId>
		</dependency>
		<dependency>
			<groupId>org.springframework.boot</groupId>
			<artifactId>spring-boot-starter-web</artifactId>
		</dependency>
		<dependency>
			<groupId>org.springframework.cloud</groupId>
			<artifactId>spring-cloud-bus</artifactId>
		</dependency>
		<dependency>
			<groupId>org.springframework.cloud</groupId>
			<artifactId>spring-cloud-starter-config</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-stream-binder-rabbit</artifactId>
		</dependency>

		<dependency>
			<groupId>org.springframework.boot</groupId>
			<artifactId>spring-boot-starter-test</artifactId>
			<scope>test</scope>
		</dependency>
	</dependencies>

	<dependencyManagement>
		<dependencies>
			<dependency>
				<groupId>org.springframework.cloud</groupId>
				<artifactId>spring-cloud-dependencies</artifactId>
				<version>${spring-cloud.version}</version>
				<type>pom</type>
				<scope>import</scope>
			</dependency>
		</dependencies>
	</dependencyManagement>

	<build>
		<plugins>
			<plugin>
				<groupId>org.springframework.boot</groupId>
				<artifactId>spring-boot-maven-plugin</artifactId>
			</plugin>
		</plugins>
	</build>

	<repositories>
		<repository>
			<id>spring-milestones</id>
			<name>Spring Milestones</name>
			<url>https://repo.spring.io/milestone</url>
		</repository>
	</repositories>

</project>

配置appication.yml文件：

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server:
  port: 8881
spring:
  application:
	name: config-client
  cloud:
	config:
	  label: master
	  profile: dev
	  discovery:
		enabled: true
		service-id: config-server
	bus:
	  enabled: true
	  trace:
		enabled: true
  rabbitmq:
	host: localhost
	port: 5672
	username: guest
	password: guest
eureka:
  client:
	service-url:
	  defaultZone: http://localhost:9871/eureka/
management:
  endpoints:
	web:
	  exposure:
		include: bus-refresh

第七步 配置主程序

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import org.springframework.beans.factory.annotation.Value;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.client.discovery.EnableDiscoveryClient;
import org.springframework.cloud.context.config.annotation.RefreshScope;
import org.springframework.cloud.netflix.eureka.EnableEurekaClient;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

@SpringBootApplication
@EnableEurekaClient
@EnableDiscoveryClient
@RestController
@RefreshScope
public class ConfigClientApplication {

	public static void main(String[] args) {
		SpringApplication.run(ConfigClientApplication.class, args);
	}

	@Value("${hello}")
	String hello;

	@RequestMapping(value = "/hello")
	public String hello(){
		return "hello=" + hello;
	}
}

第八步：创建config-client2工程：

配置同config-client，修改端口号：8882

第九步 启动程序

依次启动eureka-servr,config-server,config-client,config-client2

分别访问：http://localhost:8881/hello、http://localhost:8882/hello返回信息：

hello=hello,handsomeman.

这时我们去代码仓库将hello的值改为“hello=hello,every handsomeman.”，即改变配置文件hello的值。 如果是传统的做法，需要重启服务，才能达到配置文件的更新。此时，我们只需要发送post请求，记住 一定要post请求：http://localhost:8881/actuator/bus-refresh，你会发现config-client会重新读取配置文件

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Fetching config from server at : http://localhost:8888
Located environment: name=config-client, profiles=[dev], label=master, version=6591dd45233b34ef195417ee4e2ad9002eaddb79, state=null
Located property source: CompositePropertySource {name='configService', propertySources=[MapPropertySource {name='configClient'}, MapPropertySource {name='https://github.com/mochengyanliu/SpringCloudConfig/dev/config-client-dev.properties'}]}

再次分别访问：http://localhost:8881/hello、http://localhost:8882/hello返回信息：

hello=hello,every handsomeman.

另外，/actuator/bus-refresh接口可以指定服务，即使用”destination”参数，比如 “/actuator/bus-refresh?destination=user:**” 即刷新服务名为user的所有服务。

源码下载：

https://github.com/mochengyanliu/SpringCloudLearn/tree/master/section8

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