What is RefreshScope ？
RefreshScope(org.springframework.cloud.context.scope.refresh)是spring cloud提供的一种特殊的scope实现，用来实现配置、实例热加载。 RefreshScope继承关系如下所示
Scope -> GenericScope -> RefreshScope，Scope是Spring2.0开始有的概念，主要是用于定义spring的注入范围。GenericScope 是 一个通用Scope实现。
2. RefreshScope实现原理
要想了解RefreshScope的实现原理，首先要了解Scope在Springboot生命周期中涉及到的功能点
2.1 Scope在创建Bean实例
AbstractBeanFactory#doGetBean
此方法返回一个Bean对象
/*
* Return an instance, which may be shared or independent, of the specified bean.
*/
protected <T> T doGetBean(...) {
final String beanName = transformedBeanName(name);
Object bean;
// Eagerly check singleton cache for manually registered singletons.
Object sharedInstance = getSingleton(beanName);
if (sharedInstance != null && args == null) {
...
bean = getObjectForBeanInstance(sharedInstance, name, beanName, null);
}
}else {
// Fail if we're already creating this bean instance:
// We're assumably within a circular reference.
...
// Check if bean definition exists in this factory.
...
// Guarantee initialization of beans that the current bean depends on.
....
//Create bean instance.
if (mbd.isSingleton()) {
...
} else if (mbd.isPrototype())
...
{
String scopeName = mbd.getScope();
final Scope scope = this.scopes.get(scopeName);
Object scopedInstance = scope.get(beanName, new ObjectFactory<Object>() {...
});
...
}
...
}