1?? 工程結構

nacos-demo├── pom.xml└── src├── main│   ├── java│   │   └── com.example.nacosdemo│   │       ├── NacosDemoApplication.java│   │       ├── config│   │       │   └── AppProperties.java│   │       └── controller│   │           └── HelloController.java│   └── resources│       └── bootstrap.yml

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2?? pom.xml

使用 Spring Boot + Spring Cloud Alibaba Nacos Config 依賴：

<project><modelVersion>4.0.0</modelVersion><groupId>com.example</groupId><artifactId>nacos-demo</artifactId><version>1.0.0</version><properties><java.version>17</java.version><spring.boot.version>3.2.5</spring.boot.version><spring.cloud.version>2023.0.1</spring.cloud.version><spring.cloud.alibaba.version>2023.0.1.0</spring.cloud.alibaba.version></properties><dependencyManagement><dependencies><dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-dependencies</artifactId><version>${spring.boot.version}</version><type>pom</type><scope>import</scope></dependency><dependency><groupId>com.alibaba.cloud</groupId><artifactId>spring-cloud-alibaba-dependencies</artifactId><version>${spring.cloud.alibaba.version}</version><type>pom</type><scope>import</scope></dependency><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><dependencies><!-- Web --><dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-web</artifactId></dependency><!-- Nacos Config --><dependency><groupId>com.alibaba.cloud</groupId><artifactId>spring-cloud-starter-alibaba-nacos-config</artifactId></dependency><!-- 方便調試 --><dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-actuator</artifactId></dependency></dependencies>
</project>

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3?? bootstrap.yml

bootstrap.yml 會在應用啟動早期加載，確保 Nacos 配置優先注入：

spring:application:name: nacos-democloud:nacos:config:server-addr: 127.0.0.1:8848namespace: publicgroup: DEFAULT_GROUPfile-extension: yamlrefresh-enabled: truemanagement:endpoints:web:exposure:include: "*"

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4?? 配置類 AppProperties.java

package com.example.nacosdemo.config;import org.springframework.boot.context.properties.ConfigurationProperties;
import org.springframework.cloud.context.config.annotation.RefreshScope;
import org.springframework.stereotype.Component;@Component
@RefreshScope // 支持動態刷新
@ConfigurationProperties(prefix = "app")
public class AppProperties {private String message = "default message";public String getMessage() {return message;}public void setMessage(String message) {this.message = message;}
}

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5?? 控制器 HelloController.java

package com.example.nacosdemo.controller;import com.example.nacosdemo.config.AppProperties;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RestController;@RestController
public class HelloController {private final AppProperties appProperties;public HelloController(AppProperties appProperties) {this.appProperties = appProperties;}@GetMapping("/hello")public String hello() {return "Message from Nacos: " + appProperties.getMessage();}
}

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6?? 啟動類 NacosDemoApplication.java

package com.example.nacosdemo;import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;@SpringBootApplication
public class NacosDemoApplication {public static void main(String[] args) {SpringApplication.run(NacosDemoApplication.class, args);}
}

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7?? Nacos 配置中心添加配置

在 Nacos 控制臺添加一個配置：

• Data ID: nacos-demo.yaml（與 spring.application.name + .yaml 對應）
• Group: DEFAULT_GROUP
• 內容：

app:message: Hello from Nacos!

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8?? 啟動與測試

1. 啟動本地 Nacos（默認端口 8848）
2. 啟動 Spring Boot 應用
3. 訪問 http://localhost:8080/hello → 返回 Message from Nacos: Hello from Nacos!
4. 在 Nacos 控制臺修改 app.message → 保存
5. 再次訪問 /hello，無需重啟應用即可看到新值（因為 @RefreshScope + refresh-enabled: true）

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? 總結
這個示例展示了：

• @ConfigurationProperties 從 Nacos 拉取配置
• @RefreshScope 支持動態刷新
• bootstrap.yml 提前加載遠程配置
• 最小依賴組合，直接可運行

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