nacos配置中心无法动态刷新

public static void main(String[] args) throws InterruptedException{
    ConfigurableApplicationContext applicationContext = SpringApplication.run(StartApplication.class, args);
    while(true){
        ConfigurableEnvironment environment = applicationContext.getEnvironment();
        EnvConfig.LOG_ON_OFF_VAL = environment.getProperty(EnvConfig.LOG_ON_OFF_KEY);
        TimeUnit.SECONDS.sleep(2);
    }
}