为什么我需要自动接线/注入场的二传手? [英] Why do I need a setter for autowired / injected field?

问题描述

我有一个豆子:

    <bean id="BasketLogic" class="efco.logic.EfcoBasketLogic" autowire="byType">
        <property name="documentLogic" ref="DocumentLogic" />
        <property name="stateAccess" ref="StateAccess" />
        <property name="contextAccess" ref="ContextAccess" />
    </bean>

  <bean id="EfcoErpService" autowire="byType" class="efco.erp.service.EfcoErpServiceImpl">
    <constructor-arg ref="ErpConnector"/>
  </bean>

documentLogic ， stateAccess 和 contextAccess 是 BasketLogicImpl

我没有<context:component-scan />

EfcoBasketLogic.java:

EfcoBasketLogic.java:

public class EfcoBasketLogic extends BasketLogicImpl {

        @Inject
        private EfcoErpService erpService;
    ...
    ...
    ...
}

除非我提供设置器，否则

erpService为 null .但为什么?我以为在进行自动装配的地方不需要二传手?可能是BasketLogicImpl负责吗?

erpService is null, unless I provide a setter. But why? I thought a setter isn't needed where autowiring is taking place? Could it be that BasketLogicImpl is responsible for that?

推荐答案

您需要使用setter，因为除非通过<context:component-scan />或<context:annotation-config />告知spring，否则不会检测到注释.由于您指定了autowire="byType"，因此检测到Setter.

You need to use a setter because annotations are not detected unless spring is told so through either <context:component-scan /> or <context:annotation-config />. Setter is detected because you specified autowire="byType".

您可能还会发现此问题和答案也很有帮助:何时在春季使用自动装配

You may find this question and answer helpful as well: When to use autowiring in Spring

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