Spring Cloud官網: https://spring.io/projects/spring-cloud

本篇主要講Spring Cloud Config，參考內容如下：

• Spring Cloud Config 2.2.1.RELEASE參考文檔
• Spring Cloud Config 實現配置中心，看這一篇就夠了

實現簡單的配置中心

配置文件就在Spring官方提供的配置倉庫：https://github.com/spring-cloud-samples/config-repo

1 創建配置中心服務端

完整代碼參考：https://github.com/sxpujs/spring-cloud-examples/tree/master/config/config-server

1 新建Spring Boot項目，引入config-server

<dependency>
    <groupId>org.springframework.cloud</groupId>
    <artifactId>spring-cloud-config-server</artifactId>
</dependency>

2 配置config相關的配置項

bootstrap.yml

spring:
  application:
    name: foo # 應用名
  profiles:
    active: dev,mysql

application.yml

server:
  port: 8888

spring:
  cloud:
    config:
      server:
        git:
          uri: https://github.com/spring-cloud-samples/config-repo
          basedir: target/config

3 Application啟動類，增加相關註解：

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

4 啟動服務，進行相關測試

curl localhost:8888/foo/development

{
   "name" : "foo",
   "profiles" : ["development"],
   "propertySources" : [
      {"name":"https://github.com/spring-cloud-samples/config-repo/foo-development.properties",
       "source":{"bar":"spam",
                 "foo":"from foo development"}},
      {"name":"https://github.com/spring-cloud-samples/config-repo/foo.properties", 
       "source":{"foo":"from foo props",
                 "democonfigclient.message":"hello spring io"}},
      {"name":"https://github.com/spring-cloud-samples/config-repo/application.yml (document #0)", 
       "source":{"info.url" : "https://github.com/spring-cloud-samples",
                 "info.description":"Spring Cloud Samples",
                 "foo":"baz",
                 "eureka.client.serviceUrl.defaultZone":"http://localhost:8761/eureka/"}}
   ]
}


# 訪問不存在的profile（mysql）
curl http://localhost:8888/foo/mysql
{
  "name":"foo",
  "profiles":["mysql"],
  "propertySources":[
    {"name":"https://github.com/spring-cloud-samples/config-repo/foo.properties",
     "source":{"foo":"from foo props",
               "democonfigclient.message":"hello spring io"}},
    {"name":"https://github.com/spring-cloud-samples/config-repo/application.yml (document #0)",
     "source":{"info.description":"Spring Cloud Samples",
               "info.url":"https://github.com/spring-cloud-samples",
               "eureka.client.serviceUrl.defaultZone":"http://localhost:8761/eureka/",
               "foo":"baz"}}
  ]
}


curl http://localhost:8888/foo-dev.yml  # 從結果來看，包含了

bar: spam
democonfigclient:
  message: hello from dev profile
eureka:
  client:
    serviceUrl:
      defaultZone: http://localhost:8761/eureka/
foo: from foo development
info:
  description: Spring Cloud Samples
  url: https://github.com/spring-cloud-samples
my:
  prop: from application-dev.yml

2 創建配置中心客戶端，使用配置

完整代碼參考：https://github.com/sxpujs/spring-cloud-examples/tree/master/config/config-client

1 引用相關的maven依賴。

<dependency>
    <groupId>org.springframework.cloud</groupId>
    <artifactId>spring-cloud-starter-config</artifactId>
</dependency>

<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-web</artifactId>
</dependency>

<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-actuator</artifactId>
</dependency>

2 配置文件

bootstrap.yml

spring:
  profiles:
    active: dev
  cloud:
    config:
      uri: http://localhost:8888
  application:
    name: myapp

application.yml

management:
  endpoint:
    shutdown:
      enabled: false
  endpoints:
    web:
      exposure:
        include: "*"   # * 在yaml 文件屬於關鍵字，所以需要加引號

3 Application啟動類

@SpringBootApplication
@RestController
public class ConfigClientApplication {

    @Value("${foo}")
    private String foo;

    @Value("${my.prop}")
    private String myProp;

    @RequestMapping("/")
    public String home() {
        return "Hello World!" + myProp + "," + foo;
    }

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

4 驗證數據

訪問env埠，註意：從Spring Boot 2.x開始，不能直接訪問 http://localhost:8080/env，需要添加actuator。

curl localhost:8080    # 可以看出my.prop這個屬於是來自application-dev.yml，foo來自application.yml

Hello World!from application-dev.yml,baz


curl localhost:8080/actuator/env|json_pp

{
   "activeProfiles" : [],
   "propertySources" : [
      {"name":"server.ports","properties":{"local.server.port":{"value":8080}}},
      {
         "name" : "bootstrapProperties-https://github.com/spring-cloud-samples/config-repo/application.yml (document #0)",
         "properties" : {
            "info.url" : {"value" : "https://github.com/spring-cloud-samples"},
            "eureka.client.serviceUrl.defaultZone" : {"value" : "http://localhost:8761/eureka/"},
            "foo" : {"value" : "baz"},
            "info.description" : {"value" : "Spring Cloud Samples"}
         }
      }
   ]
}