问题描述
说我需要依赖Spring的几个实现。我有一个 AccountService 接口和两个实现： DefaultAccountServiceImpl 和 SpecializedAccountServiceImpl 。
Say I need to rely on several implementations of a Spring bean. I have one AccountService interface and two implementations: DefaultAccountServiceImpl and SpecializedAccountServiceImpl.
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这怎么可能（注入一个或另一个实现）在Spring？
How is this possible (injecting one or the other implementation) in Spring?
以下注入使用哪种实现？
Which implementation will the following injection use?
@Autowired
private AccountService accountService;
推荐答案
广告。 1：你可以使用或使用 @Resource 进行自动装配，而不是 @自动装配，默认为字段名称而不是类型。
Ad. 1: you can use @Qualifier annotation or autowire using @Resource as opposed to @Autowired which defaults to field name rather than type.
广告。 2：它将在运行时失败，说两个bean正在实现此接口。如果您的其中一个bean另外进行注释，在按类型自动装配时将首选。
Ad. 2: It will fail at runtime saying that two beans are implementing this interface. If one of your beans is additionally annotated with @Primary, it will be preferred when autowiring by type.
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