springcloud情操陶冶-初识springcloud

许久之前便听到了springcloud如雷贯耳的大名，但是不曾谋面，其主要应用于微服务的相关架构。笔者对微服务并不是很了解，但其既然比较出众，遂也稍微接触研究下

springcloud特性

springcloud作为spring团队的微服务架构，其有如下的特性(摘自官方文档)

Distributed/versioned configuration(分布式/版本化配置)
Service registration and discovery(服务注册与发现)
Routing(路由)
Service-to-service calls(服务间远程调用)
Load balancing(负载均衡)
Circuit Breakers(熔断器)
Distributed messaging(分布式消息)

应该就是微服务的相关特性，笔者不对上述的概念进行阐述，读者可相应的查阅相关文档

springcloud config

springcloud板块下有很多的分支，根本看不过来，就挑笔者比较感兴趣的配置管理springcloud config作为分析的入口把。具体的使用以及概念本文就不展开了，在官方文档上都有，笔者喜欢从源码角度看下springcloud是如何整合springboot进行扩展的

MAVEN依赖

根据官方的例子，笔者最后还是通过IDEA开发工具引入Spring Initializr构建工具来生成springcloud config的相关maven配置

<?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.example</groupId>
	<artifactId>cloud-demo</artifactId>
	<version>0.0.1-SNAPSHOT</version>
	<name>cloud-demo</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>
		<!--server也依赖client板块-->
		<dependency>
			<groupId>org.springframework.cloud</groupId>
			<artifactId>spring-cloud-config-server</artifactId>
		</dependency>
		<!--client板块引入，如果只需要客户端，则只引入此依赖即可-->
		<dependency>
			<groupId>org.springframework.cloud</groupId>
			<artifactId>spring-cloud-starter-config</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>

其依托于spring-boot-starter-parent板块进行构建，上述的简单配置其实引入了spring/springboot/springcloud三大板块及其相应依赖，具体就不展示了，读者可自行查看

config启动方式

可以分几种情况来启动相应的服务

linux方式启动

$ cd cloud-demo
$ ./mvnw spring-boot:run

window方式启动

> cd cloud-demo
> call mvnw.cmd spring-boot:run

IDEA方式启动，写一个启动类携带上**@EnableConfigServer**注解即可，例如

package com.example.cloud.app;

import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.boot.builder.SpringApplicationBuilder;
import org.springframework.cloud.config.server.EnableConfigServer;

/**
 * @author nanco
 * -------------
 * cloud-demo
 * -------------
 * @create 
 * @descrption
 **/
@SpringBootApplication
@EnableConfigServer
public class CloudConfigApp {

    public static void main(String[] args) {
        SpringApplicationBuilder appBuilder = new SpringApplicationBuilder(CloudConfigApp.class);
        // load certain properties
        appBuilder.properties("spring.config.name=configapp").run(args);
    }
}