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/> <!-- lookup parent from repository -->
</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
image
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。
image
在次访问http://localhost:8080/getTitle，如下图
image
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：
image
访问http://localhost:15672/#/如下图
image
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/> <!-- lookup parent from repository -->
</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/，可以看到
image
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：
image
image
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：
image
image
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
