消息总线

短命女 2022-05-26 03:29 225阅读 0赞

SpringCloudBus：事件、消息总线，用于在集群（例如，配置变化事件）中传播状态变化，可与Spring Cloud Config联合实现热部署。

在上一篇写出了springcloud对微服务的集中配置，那么就出现了一个问题，如果修改配置了怎么实现不需重启服务来实现配置的更新，下面有集中解决方法。

1.使用/refresh手动刷新配置

缺点：单点刷新，如果集群服务多的话，无论是工作量还是维护上都十分麻烦。

使用上一篇的config-client服务，加入依赖，

spring-boot-starter-actuator

pom文件如下：

<?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>
    
    	<groupId>com.dalaoyang</groupId>
    	<artifactId>springcloud_config_client</artifactId>
    	<version>0.0.1-SNAPSHOT</version>
    	<packaging>jar</packaging>
    
    	<name>springcloud_config_client</name>
    	<description>springcloud_config_client</description>
    
    	<parent>
    		<groupId>org.springframework.boot</groupId>
    		<artifactId>spring-boot-starter-parent</artifactId>
    		<version>1.5.9.RELEASE</version>
    		<relativePath/> 
    	</parent>
    
    	<properties>
    		<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
    		<project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
    		<java.version>1.8</java.version>
    		<spring-cloud.version>Edgware.SR1</spring-cloud.version>
    	</properties>
    
    	<dependencies>
    		<dependency>
    			<groupId>org.springframework.cloud</groupId>
    			<artifactId>spring-cloud-starter-eureka</artifactId>
    		</dependency>
    
    		<dependency>
    			<groupId>org.springframework.boot</groupId>
    			<artifactId>spring-boot-starter-test</artifactId>
    			<scope>test</scope>
    		</dependency>
    
    		<dependency>
    			<groupId>org.springframework.cloud</groupId>
    			<artifactId>spring-cloud-starter-config</artifactId>
    		</dependency>
    
    		<dependency>
    			<groupId>org.springframework.boot</groupId>
    			<artifactId>spring-boot-starter-actuator</artifactId>
    		</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>
    
    
    </project>

在Controller类上加入@RefreshScope注解，由于上一篇controller写在了启动类上，所以直接加在启动类上，代码如下：

package com.dalaoyang;
    
    import org.springframework.beans.factory.annotation.Value;
    import org.springframework.boot.SpringApplication;
    import org.springframework.boot.autoconfigure.SpringBootApplication;
    import org.springframework.cloud.context.config.annotation.RefreshScope;
    import org.springframework.web.bind.annotation.RequestMapping;
    import org.springframework.web.bind.annotation.RestController;
    
    @SpringBootApplication
    @RestController
    @RefreshScope
    public class SpringcloudConfigClientApplication {
    
    	public static void main(String[] args) {
    		SpringApplication.run(SpringcloudConfigClientApplication.class, args);
    	}
    
    
    	@Value("${title}")
    	String title;
    
    	@RequestMapping("/getTitle")
    	public String getTitle(){
    		return title;
    	}
    
    }

配置文件新增配置management.security.enabled=false，在刷新时关闭安全验证。

代码如下：

spring.application.name=config-client
    spring.cloud.config.label=master
    spring.cloud.config.profile=test
    spring.cloud.config.uri= http://localhost:9000/
    
    ##注册中心地址
    eureka.client.service-url.defaultZone=http://eureka.dalaoyang.cn/eureka/
    
    ## 刷新时，关闭安全验证
    management.security.enabled=false

分别启动项目config-server，config-client。访问http://localhost:8080/getTitle，结果如下图

![1][]

修改git上配置，修改为dalaoyang\_test\_change，在次请求，结果没有改变，使用postman或者其他工具post请求http://localhost:8080/getTitle看到返回如下结果。

![2][]

在次访问http://localhost:8080/getTitle，如下图

![3][]

2.使用springcloudbus刷新配置

springcloudbus需要使用轻量消息代理，本文使用rabbitmq，启动rabbitmq如下图：

![4][]

访问http://localhost:15672/\#/如下图

![5][]

新建项目springcloud\_bus，同时改造config-client，pom文件加入bus依赖，代码如下：

<?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>
    
    	<groupId>com.dalaoyang</groupId>
    	<artifactId>springcloud_bus</artifactId>
    	<version>0.0.1-SNAPSHOT</version>
    	<packaging>jar</packaging>
    
    	<name>springcloud_bus</name>
    	<description>springcloud_bus</description>
    
    	<parent>
    		<groupId>org.springframework.boot</groupId>
    		<artifactId>spring-boot-starter-parent</artifactId>
    		<version>1.5.9.RELEASE</version>
    		<relativePath/> 
    	</parent>
    
    	<properties>
    		<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
    		<project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
    		<java.version>1.8</java.version>
    		<spring-cloud.version>Edgware.SR1</spring-cloud.version>
    	</properties>
    
    	<dependencies>
    		<dependency>
    			<groupId>org.springframework.cloud</groupId>
    			<artifactId>spring-cloud-starter-eureka</artifactId>
    		</dependency>
    
    		<dependency>
    			<groupId>org.springframework.boot</groupId>
    			<artifactId>spring-boot-starter-test</artifactId>
    			<scope>test</scope>
    		</dependency>
    
    		<dependency>
    			<groupId>org.springframework.cloud</groupId>
    			<artifactId>spring-cloud-starter-config</artifactId>
    		</dependency>
    
    		<dependency>
    			<groupId>org.springframework.boot</groupId>
    			<artifactId>spring-boot-starter-actuator</artifactId>
    		</dependency>
    
    		<dependency>
    			<groupId>org.springframework.cloud</groupId>
    			<artifactId>spring-cloud-starter-bus-amqp</artifactId>
    		</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>
    
    
    </project>

加入rabbitmq配置，配置文件如下：

spring.rabbitmq.host=localhost
    spring.rabbitmq.port=5672
    spring.rabbitmq.username=guest
    spring.rabbitmq.password=guest
    
    ##端口号
    server.port=8881
    
    ## 刷新时，关闭安全验证
    management.security.enabled=false
    
    spring.application.name=config-client
    spring.cloud.config.label=master
    spring.cloud.config.profile=test
    spring.cloud.config.uri= http://localhost:9000/
    
    ##注册中心地址
    eureka.client.service-url.defaultZone=http://eureka.dalaoyang.cn/eureka/

启动类加入注解@RefreshScope，代码如下：

package com.dalaoyang;
    
    import org.springframework.beans.factory.annotation.Value;
    import org.springframework.boot.SpringApplication;
    import org.springframework.boot.autoconfigure.SpringBootApplication;
    import org.springframework.cloud.context.config.annotation.RefreshScope;
    import org.springframework.web.bind.annotation.RequestMapping;
    import org.springframework.web.bind.annotation.RestController;
    
    @SpringBootApplication
    @RestController
    @RefreshScope
    public class SpringcloudBusApplication {
    
    	public static void main(String[] args) {
    		SpringApplication.run(SpringcloudBusApplication.class, args);
    	}
    
    
    	@Value("${title}")
    	String title;
    
    	@RequestMapping("/getTitle")
    	public String getTitle(){
    		return title;
    	}
    }

config-client加入同样依赖和配置，重启config-client，启动springcloud\_bus，先去[http://eureka.dalaoyang.cn/][http_eureka.dalaoyang.cn]，可以看到

![6][]

先将git上配置改回dalaoyang\_test，分别请求http://localhost:8881/getTitle和http://localhost:8080/getTitle结果如下：

![7][]

![8][]

然后用postman使用post请求访问http://localhost:8881/bus/refresh

再次分别请求http://localhost:8881/getTitle和http://localhost:8080/getTitle结果如下：

![9][]

![10][]

从图中可以看出刷新配置成功。

3.局部刷新配置，配置与第2种方法一样，只是在使用postman刷新时略加改变，在本文中使用http://localhost:8881/bus/refresh?destination=config-client:8881可以刷新服务名为config-client端口为8881的服务，如果想要刷新服务名为config-client的所有服务可以写成http://localhost:8881/bus/refresh?destination=config-client:\*\*

源码下载 ：[大老杨码云][Link 1]

个人网站：[https://www.dalaoyang.cn][https_www.dalaoyang.cn]

[1]: /images/20220526/7754add42a4645fc97fc8b638d770728.png
[2]: /images/20220526/ce4ce027ceec45459f2d2eb645029393.png
[3]: /images/20220526/e1b058d345d54bd08f8b7fc0b17f012f.png
[4]: /images/20220526/569ec5b7bea345359d717584fb53c4ea.png
[5]: /images/20220526/44a1d93cd1364c659ca6d95fdb69bb7d.png
[http_eureka.dalaoyang.cn]: http://eureka.dalaoyang.cn/
[6]: /images/20220526/04e0fab8610348a2ad5967ae459d5ed7.png
[7]: /images/20220526/b2c74df5ed5642778b6d2aaf2744f439.png
[8]: /images/20220526/5c2a0fc284d44f819e1c950e99d23723.png
[9]: /images/20220526/d3c9e9aa2cdc4630bbe35098d805df8b.png
[10]: /images/20220526/7754add42a4645fc97fc8b638d770728.png0
[Link 1]: https://gitee.com/dalaoyang/springcloud_learn.git
[https_www.dalaoyang.cn]: https://www.dalaoyang.cn/