创建无法自动连线的Spring bean

Question

I have a class A that extends B, which implements C. Currently, A takes B has an input argument and is the only defined bean that is an implementation of C, so it gets autowired whenever C is needed.

Without changing the ALL of the places where C is needed or the class structure of A/B/C, I need make B a defined bean so the same instance can be re-used. The problem is then I have 2 implementations of C (A and B). Is there a way to mark B so that it cannot be autowired?

Current:

  <bean id="A" class="A">
    <constructor-arg>
      <bean class="B">
    </constructor-arg>
  </bean>

Wanted (so same instance of B can be used elsewhere):

  <!-- TODO: Somehow mark B so it cannot be autowired -->
  <bean id="B" class="B"/>

  <bean id="A" class="A">
    <constructor-arg ref="B">
  </bean>

  <bean id="Foo" class="Foo">
    <constructor-arg ref="B">
  </bean>

Answer 1

If you want to eliminate a bean from autowiring, then you can set autowire-candidate attribute of that bean tag to false. For example consider your case(Here I am setting B bean's autowire-candidate attribute to false)

 <bean id="B" class="B" autowire-candidate="false"/>

  <bean id="A" class="A">
    <constructor-arg ref="B">
  </bean>

  <bean id="Foo" class="Foo">
    <constructor-arg ref="B">
  </bean>

Answer 2

You could use qualifiers attached to @Autowired .

Eg, if you want to wire the bean with id B , you can do the following:

@Autowired
@Qualifier("B")
private C c;