Using Nacos as Service Registry and Configuration Center in Spring Cloud

Hello, I am Wukong. In the previous article we explained the architecture of OpenFeign; this time we dive into the Nacos ecosystem. Nacos, a mature service registry and configuration center from Alibaba, is widely used as a cloud‑native standard.

1. Nacos as a Registration Center

1.1 Add Nacos discovery dependency

In the passjava-common module's pom.xml add the following dependency:

<!-- nacos discovery service component -->
<dependency>
    <groupId>com.alibaba.cloud</groupId>
    <artifactId>spring-cloud-starter-alibaba-nacos-discovery</artifactId>
</dependency>

1.2 Download and start Nacos Server

Download the Nacos Server zip from GitHub . After extracting, run the startup script according to your OS:

Linux/Unix/Mac: sh startup.sh -m standalone Windows: cmd startup.cmd If Windows shows

Please set the JAVA_HOME variable in your environment, We need java(x64)! jdk8 or later is better!

, edit startup.cmd and replace %JAVA_HOME% with the actual JDK path, e.g. C:\Program Files\Java\jdk1.8.0_131. After correction the server starts successfully.

1.3 Configure each microservice to point to Nacos

Add the server address to the application.yml of each service (passjava‑question, passjava‑channel, passjava‑content, passjava‑member, passjava‑study):

spring:
  cloud:
    nacos:
      discovery:
        server-addr: 127.0.0.1:8848

1.4 Add @EnableDiscoveryClient annotation

@EnableDiscoveryClient
@MapperScan("com.jackson0714.passjava.question.dao")
@SpringBootApplication
public class PassjavaQuestionApplication {
    public static void main(String[] args) {
        SpringApplication.run(PassjavaQuestionApplication.class, args);
    }
}

1.5 Set service name

spring:
  application:
    name: passjava-question

1.6 Access Nacos UI

Open http://localhost:8848/nacos/index.html#/login and log in with username nacos and password nacos. The UI lists all registered services such as passjava-channel, passjava-member, etc.

2. Nacos as a Configuration Center

2.1 Traditional local configuration

Define properties in application.properties:

member.nickname = "悟空聊架构"
member.age = "18"

Inject them with @Value in a controller and expose an endpoint to return the values.

2.2 Add Nacos Config dependency

<dependency>
    <groupId>com.alibaba.cloud</groupId>
    <artifactId>spring-cloud-starter-alibaba-nacos-config</artifactId>
</dependency>

2.3 Bootstrap configuration

Create bootstrap.properties (higher priority than other config files) for the member service:

spring.application.name=passjava-member
spring.cloud.nacos.config.server-addr=127.0.0.1:8848

2.4 Add configuration in Nacos UI

Create a Data ID passjava-member.properties in the DEFAULT_GROUP with content:

member.nick="悟空"
member.age=10

2.5 Enable dynamic refresh

Annotate a controller with @RefreshScope so that changes in Nacos are pushed without restarting the service:

@RefreshScope
@RestController
@RequestMapping("member/sample")
public class SampleController {}

The console logs show refresh events such as:

Refresh keys changed: [member.age]
... dataId=passjava-member.properties, group=DEFAULT_GROUP ...

2.6 Test the result

Calling http://localhost:10000/member/sample/test-local-config returns the nickname and age defined in Nacos, confirming that the configuration is live.

2.7 Namespaces

To isolate configurations per microservice, create a namespace for each (e.g., passjava-member) and set the namespace in bootstrap.properties:

spring.cloud.nacos.config.namespace=passjava-member

After adding configuration under that namespace, the service retrieves the correct values.

2.8 Groups (environments)

Use groups to separate dev, test, prod configurations. Create a group prod in Nacos and set it in bootstrap.properties:

spring.cloud.nacos.config.group=prod

Requests now return the values from the prod group.

2.9 Multiple configuration sets

Complex configurations (datasource, mybatis‑plus, etc.) can be split into separate YAML files and imported via extension-configs:

spring.cloud.nacos.config.extension-configs[0].data-id=datasource.yml
spring.cloud.nacos.config.extension-configs[0].group=dev
spring.cloud.nacos.config.extension-configs[0].refresh=true
... (similar entries for mybatis.yml and more.yml)

After adding these files in Nacos and enabling refresh, the service can read them at runtime.

Conclusion

Using Nacos you can:

Introduce the Nacos dependency.

Configure the Nacos data source.

Manage configuration data sets (DataId).

Enable dynamic refresh with @RefreshScope.

Inject values via @Value.

Prefer configuration‑center values over local files.

Separate configurations by namespace.

Separate environments by group.

Use multiple configuration sets via extension-configs.

The underlying principles of Nacos are continuously evolving; happy new year and keep learning!