问题描述
我有一个具有注入属性 private int url 的bean BeanA：
I have a bean BeanA with injected property private int url:
class BeanA { @Value(${"db.url"}) private String url; private DbConnection connection; }
让我们说这个 Value 注释是类似于Spring Value 。在初始化期间，将通过使用url字段中的注入属性来初始化连接。在 BeanA 中还有一些 PostConstruct和PreDestroy 方法。
我的问题是： url 属性更改后，是否可以动态地重新实例化 BeanA 。我有检测属性变化的机制。现在，我只重新注入该URL，但是我想重新创建此Bean，初始化新的连接，然后在所有Dependetn Bean中重新注入此Bean。我不使用Spring Cloud Config。
Let us say this Value annotation is similar to Spring Value. During initialization, connection will be initialized by using injected property into url field. And also there is some PostConstruct and PreDestroy methods in BeanA.My question is: is it possible to dynamically reinstantiate BeanA when url property changed. I have mechanism of detecting property change. For now, I just re-inject this url only, but I want to recreate this bean, initialize new connection and re-inject this bean in all dependetn beans. I dont use Spring Cloud Config.
推荐答案
如果您根本不使用spring，我建议：
If you don't use spring at all, I suggest:
- 将 bean保持不变。 （因此它将用作Singleton。）
- 在Bean中添加一个方法：getConnection（）
- 属性更改时，重新创建一个新连接
- 任何需要连接的组件都将始终调用Bean的getConnection（），并且将始终获取最新的连接实例。
- Leave the "bean" as is. (So it will serve as Singleton).
- add a method in the bean: getConnection()
- When the property changes, recreate a new connection inside that bean.
- Any component that needs the connection will always call the bean's getConnection() and it will always get the most updated connection instance.
或
您可能希望使用代理设计模式来使用bean由客户端但在内部引用另一个连接Bean（目标 Bean），并且目标可以用全新的Bean的新实例代替。但是总是，客户端/用户对代理拥有相同的引用。
You might want to use a Proxy design pattern where your bean is used by the client but internally refers to another connection bean (the "target" bean) and the target may be replaced with a new instanse of a completely new bean. But always, the client/user holds the same reference to the proxy.
这篇关于如果某些注入的属性已更改，则重新注入CDI bean的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持！