Spring抛出错误：Bean定义是抽象的 [英] Spring throws the error: Bean definition is abstract

问题描述

我需要一些关于下一个主题的帮助。

我有一个bean的层次结构，就像那样：

 < bean id =fatherclass =myPackage.Fatherabstract =true/> 
 
< bean id =childAclass =myPackage.ChildAparent =father> 
< property name =atrib1value =hello>< / property> 
< / bean> 
 
< bean id =childBclass =myPackage.ChildBparent =father> 
< property name =atrib2value =bye>< / property> 
< property name =atrib3value =other>< / property> 
< / bean> 
  

我需要创建另一个包含对抽象类的引用的bean。然后在运行时，我需要能够初始化TYPEmyPackage.Father的变量，并使用任何子类（多态机制）实例化它。我的意思是这样的：

 < bean id =referenceclass =myPackage.Another> 
< property name =atrib4ref =father>< / property> 
< / bean> 
  

请注意，引用（myPackage.Another的实例）不是myPackage.Father的子类。但是使用这些行Spring会抛出下一个错误：

  Bean定义是抽象的
  

我怎么处理它？<​​/ p>

我感谢任何帮助，提前谢谢！

解决方案

首先，抽象bean与抽象类
无关，它们甚至不需要映射到一个类。它们用于对另一个bean共享的公共属性进行分组。但是你不能使用抽象bean作为引用来连接另一个bean中的属性。
如果你的bean myPackage.Another有一个类型为myPackage.Father的引用，你的子bean可以赋值给myPackage.Father，那么你可以在myPackage中连接childA或childB
。像这样的另一个bean

 < bean id =referenceclass =myPackage.Another> 
< property name =atrib4ref =childA>< / property> 
< / bean> 
  

I need some help with next topic.

I have a hierarchy of beans, just like that:

<bean id="father" class="myPackage.Father" abstract="true"/>  

<bean id="childA" class="myPackage.ChildA" parent="father">    
        <property name="atrib1" value="hello"></property>  
</bean>  

<bean id="childB" class="myPackage.ChildB" parent="father">  
        <property name="atrib2" value="bye"></property>  
        <property name="atrib3" value="other"></property>  
</bean>  

I need to create another bean which contains a reference to the abstract class. Then at run-time, I will need to be able to initialize a variable of TYPE "myPackage.Father" and instantiate it with any of the children classes (the polymorphism mechanism). I mean something like that:

<bean id="reference" class="myPackage.Another"> 
        <property name="atrib4" ref="father"></property>
</bean>  

Note that reference (an instance of myPackage.Another) is not a subclass of myPackage.Father. But with these lines Spring throws the next error:

Bean definition is abstract

How could I deal with it?

I appreciate any help, thanks in advance!

解决方案

First of all abstract bean has nothing to do with the abstract class they don't even need to be mapped to a class.They are used to group the common properties shared by another beans.But you can not use an abstract bean as a ref to wire a property in another bean. If your bean myPackage.Another has a reference of type myPackage.Father and your child beans are assignable (either extends of implements) to myPackage.Father then you can wire either childA or childB in your myPackage.Another bean like this

 <bean id="reference" class="myPackage.Another"> 
            <property name="atrib4" ref="childA"></property>
    </bean>

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