Spring Prototype范围内的bean在单例中

问题描述

我试图将prototype bean注入到singleton bean中，以使对单例bean方法的每个新调用都具有原型bean的新实例.

I am trying to inject a prototype bean in a singleton bean such that every new call to a singleton bean method has a new instance of the prototype bean.

考虑如下所示的单例豆:

Consider a singleton bean as below:

    @Component
    public class SingletonBean {
       @Autowired
       private PrototypeBean prototypeBean;

       public void doSomething() {
         prototypeBean.setX(1);
         prototypeBean.display();
       }
    }

我希望每次调用doSomething()方法时，都会使用一个新的PrototypeBean实例.

I expect that every time the doSomething() method is called, a new PrototypeBean instance is utilized.

下面是原型bean:

     @Component
     @Scope(value="prototype", proxyMode = ScopedProxyMode.TARGET_CLASS)
     public class PrototypeBean {
        Integer x;

        void setX(Integer x) {
         this.x = x;
        }

        void display() {
          System.out.println(x);
        }
    }

似乎正在发生的事情是，Spring急于在doSomething()方法中移交PrototypeBean的新实例.也就是说，doSomething()方法中的两行代码在每一行中都创建了prototypeBean的新实例.

What seems to be happening is that spring is being overeager in handing over a new instance of PrototypeBean in the doSomething() method. That is, the 2 lines of code in the doSomething() method are creating a new instance of prototypeBean in each line.

因此在第二行-prototypeBean.display()打印 NULL .

此注入的配置中缺少什么?

What is missing in configuration for this injection?

推荐答案

从Spring :

对于版本3.2 文档，文档似乎有所更改在这里可以找到这句话:

It seems the documentation has changed a bit for version 3.2 documentation where you can find this sentence:

似乎不希望您使用代理原型Bean，因为每次向BeanFactory请求它时，都会创建它的新实例.

It seems that its not expected you use a proxied prototype bean, as each time it is requested to the BeanFactory it will create a new instance of it.

要为原型bean建立某种工厂，可以使用ObjectFactory，如下所示:

In order to have a kind of factory for your prototype bean you could use an ObjectFactory as follows:

@Component
public class SingletonBean {

    @Autowired
    private ObjectFactory<PrototypeBean> prototypeFactory;

    public void doSomething() {
        PrototypeBean prototypeBean = prototypeFactory.getObject();
        prototypeBean.setX(1);
        prototypeBean.display();
    }
}

和原型bean将声明如下:

and your prototype bean would be declared as follows:

@Component
@Scope(value="prototype")
public class PrototypeBean {
    // ...
}

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