Spring FactoryBean和范围一起工作 [英] Spring FactoryBean and scopes working together

问题描述

我想一起使用FactoryBeans和范围.具体来说，我希望将由FactoryBean创建并返回的对象放入指定的(也许是自定义的)范围内.问题是要执行以下操作:

I'd like to use FactoryBeans and scopes together. Specifically, I'd like the object created and returned by a FactoryBean to be placed into a specified (perhaps custom) scope. The issue is that doing the following:

<bean class="x.y.z.TestFactoryBean" scope="test" />

导致FactoryBean本身具有作用域，并且在工厂创建的对象上具有某些不可预测的行为.我明白为什么会这样；工厂本身是一流的春季管理Bean，并且具有自己的生命周期.但是，我找不到指定工厂返回的对象本身的作用域的方法.

Results in the FactoryBean itself being scoped, and has somewhat unpredictable behaviour on the object created by the factory. I understand why this is; the factory itself is a first-class spring-managed bean, and has its own lifecycle. However, I can't find a way to specify that the object returned from the factory should itself be scoped.

另一方面，这正是我想要的(只要TestFactoryBean不实现FactoryBean接口):

On the other hand, this does exactly what I want (as long as TestFactoryBean does NOT implement the FactoryBean interface):

<bean class="x.y.z.TestFactoryBean" name="testFactory">
<bean class="x.y.z.TestBean" factory-bean="testFactory" 
      factory-method="getObject" scope="test" />

真正的问题是，如何使用真正的FactoryBeans使Spring表现得像上面第二个示例一样?

So the real question is, how can I make Spring behave like it does for the 2nd example above, but using real FactoryBeans?

推荐答案

您不能轻易地对从FactoryBean返回的bean使用自定义范围.

You can't easily use a custom scope on a bean returned from a FactoryBean.

来自Spring的 Java文档:

FactoryBeans可以支持单例和原型

FactoryBeans can support singletons and prototypes

如果希望FactoryBean的返回的bean具有原型范围，则必须实现isSingleton()方法，如下所示:

If you want the FactoryBean's returned bean to have the prototype scope, then you must implement the isSingleton() method like this:

public class TestFactoryBean implements FactoryBean<TestBean> {

  // the rest of the required methods are removed for simplicity reasons..

  public boolean isSingleton() {
        return false;
    }
}

要支持自定义范围，您必须自己实现逻辑，并且不会很直观，因为FactoryBean仅提供isSingleton()方法.对于具有自定义范围的bean，我宁愿建议使用FactoryBean之外的其他解决方案.

To support a custom scope, you have to implement the logic yourself and it will not be very intuitive, since the FactoryBean only provides the isSingleton() method. I will rather recommend using another solution than FactoryBean for beans with custom scope.

希望这会有所帮助！

这篇关于Spring FactoryBean和范围一起工作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IT屋！