我可以在运行时替换Spring bean定义吗？ [英] Can I replace a Spring bean definition at runtime?

问题描述

考虑以下情况。我有一个Spring应用程序上下文，其bean属性应该是可配置的，想想 DataSource 或 MailSender 。可变应用程序配置由一个单独的bean管理，我们称之为配置。

Consider the following scenario. I have a Spring application context with a bean whose properties should be configurable, think DataSource or MailSender. The mutable application configuration is managed by a separate bean, let's call it configuration.

管理员现在可以更改配置值，如电子邮件地址或数据库URL，我想在运行时重新初始化配置的bean。

An administrator can now change the configuration values, like email address or database URL, and I would like to re-initialize the configured bean at runtime.

假设我不能简单地修改属性上面的可配置bean（例如由 FactoryBean 或构造函数注入创建）但必须重新创建bean本身。

Assume that I can't just simply modify the property of the configurable bean above (e.g. created by FactoryBean or constructor injection) but have to recreate the bean itself.

有关如何实现这一点的任何想法？我很高兴收到有关如何组织整个配置的建议。没有什么是固定的。 ： - ）

Any thoughts on how to achieve this? I'd be glad to receive advice on how to organize the whole configuration thing as well. Nothing is fixed. :-)

编辑

稍微澄清一下：我不是询问如何更新配置或如何注入静态配置值。我将尝试一个例子：

To clarify things a bit: I am not asking how to update the configuration or how to inject static configuration values. I'll try an example:

<beans>
    <util:map id="configuration">
        <!-- initial configuration -->
    </util:map>

    <bean id="constructorInjectedBean" class="Foo">
        <constructor-arg value="#{configuration['foobar']}" />
    </bean>

    <bean id="configurationService" class="ConfigurationService">
        <property name="configuration" ref="configuration" />
    </bean>
</beans>

所以有一个使用构造函数的bean constructorInjectedBean 注射。想象一下bean的构造非常昂贵，因此使用原型范围或工厂代理不是一种选择，想想 DataSource 。

So there's a bean constructorInjectedBean that uses constructor injection. Imagine the construction of the bean is very expensive so using a prototype scope or a factory proxy is not an option, think DataSource.

我想要做的是每次更新配置时（通过 configurationService bean constructorInjectedBean 正在重新创建并重新注入应用程序上下文和依赖bean。

What I want to do is that every time the configuration is being updated (via configurationService the bean constructorInjectedBean is being recreated and re-injected into the application context and dependent beans.

我们可以放心地假设 constructorInjectedBean 是使用界面，所以代理魔术确实是一个选项。

We can safely assume that constructorInjectedBean is using an interface so proxy magic is indeed an option.

我希望这个问题更清楚一点。

I hope to have made the question a little bit clearer.

推荐答案

我可以想到一个'holder bean'方法（本质上是一个装饰器），持有者bean委托给holdee，它是持有者bean，它作为依赖注入其他人没有其他人提到持有者而是持有者。现在，当持有者bean的配置被更改时，它会重新创建持有者他的新配置并开始委托给它。

I can think of a 'holder bean' approach (essentially a decorator), where the holder bean delegates to holdee, and it's the holder bean which is injected as a dependency into other beans. Nobody else has a reference to holdee but the holder. Now, when the holder bean's config is changed, it recreates the holdee with this new config and starts delegating to it.

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