SpringBoot结合@RefreshScope实现动态刷新配置的示例

graph TD
    A[修改配置文件] --> B[发送POST刷新请求]
    B --> C[/actuator/refresh 端点]
    C --> D[RefreshScope 刷新机制]
    D --> E[销毁旧Bean并创建新Bean]
    E --> F[新配置立即生效]

<!-- pom.xml -->
<dependencies>
    <!-- Spring Boot基础依赖 -->
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-web</artifactId>
    </dependency>
    
    <!-- 配置刷新核心 -->
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-actuator</artifactId>
    </dependency>
    
    <!-- 配置中心支持 -->
    <dependency>
        <groupId>org.springframework.cloud</groupId>
        <artifactId>spring-cloud-starter</artifactId>
        <version>3.1.3</version>
    </dependency>
</dependencies>

// 主应用类
@SpringBootApplication
@EnableRefreshScope  // 关键注解：开启配置刷新能力
public class DynamicConfigApp {
    public static void main(String[] args) {
        SpringApplication.run(DynamicConfigApp.class, args);
    }
}

# 应用基础配置
app:
  feature:
    enabled: true
    timeout: 5000
    retry-count: 3
    welcome-msg: "Hello, Dynamic Config!"

# 暴露刷新端点（关键！）
management:
  endpoints:
    web:
      exposure:
        include: refresh,health,info

@Service
@RefreshScope // 标记此Bean支持动态刷新
public class FeatureService {
    
    // 注入可刷新的配置项
    @Value("${app.feature.enabled}")
    private boolean featureEnabled;
    
    @Value("${app.feature.timeout}")
    private int timeout;
    
    @Value("${app.feature.retry-count}")
    private int retryCount;
    
    @Value("${app.feature.welcome-msg}")
    private String welcomeMessage;

    public String getFeatureConfig() {
        return String.format("""
            Feature Enabled: %s
            Timeout: %d ms
            Retry Count: %d
            Message: %s
            """, featureEnabled, timeout, retryCount, welcomeMessage);
    }
}

@RestController
@RequestMapping("/config")
public class ConfigController {

    private final FeatureService featureService;

    // 构造函数注入
    public ConfigController(FeatureService featureService) {
        this.featureService = featureService;
    }

    @GetMapping
    public String getConfig() {
        return featureService.getFeatureConfig();
    }
}

curl -X POST http://localhost:8080/actuator/refresh

["app.feature.timeout", "app.feature.welcome-msg"]

// 伪代码：Spring如何实现动态刷新
public class RefreshScopeProxy implements ApplicationContextAware {
    private Object targetBean;
    
    @Override
    public Object invoke(Method method) {
        if (configChanged) {
            // 1. 销毁旧Bean
            context.destroyBean(targetBean);
            // 2. 重新创建Bean
            targetBean = context.getBean(beanName);
        }
        return method.invoke(targetBean, args);
    }
}

@Component
@RefreshScope
public class PaymentService {
    // 只有带@Value的属性会刷新
    @Value("${payment.timeout}")
    private int timeout;
    
    // 不会被刷新的属性
    private final String apiVersion = "v1.0"; 
}

@Configuration
@RefreshScope // 整个配置类可刷新
public class AppConfig {
    
    @Bean
    @RefreshScope
    public FeatureService featureService() {
        return new FeatureService();
    }
    
    @Value("${app.theme}")
    private String theme;
}

management:
  endpoint:
    refresh:
      enabled: true
  endpoints:
    web:
      exposure:
        include: refresh
      base-path: /internal  # 修改默认路径
      path-mapping:
        refresh: secure-refresh  # 端点重命名

# 添加安全认证
spring:
  security:
    user:
      name: admin
      password: $2a$10$NVM0n8ElaRgg7zWO1CxUdei7vWoQP91oGycgVNCY8GQEx.TGx.AaC

// bootstrap.yml
spring:
  cloud:
    nacos:
      config:
        server-addr: localhost:8848
        auto-refresh: true  # 开启自动刷新

# 使用Spring Cloud Bus同步刷新
curl -X POST http://host:port/actuator/bus-refresh

@PreDestroy
public void cleanUp() {
    // 清理资源
}