Spring @Qualifier注解

最新推荐文章于 2024-03-18 09:00:52 发布

原创最新推荐文章于 2024-03-18 09:00:52 发布 · 209 阅读

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本文介绍了一个具体的Spring框架中依赖注入的示例。通过两个不同的Invoice Service实现展示如何使用@Qualifier注解确保注入正确的Bean。这有助于理解在多个实现存在的情况下如何精确指定所需的组件。

原创转载请注明出处：http://agilestyle.iteye.com/blog/2330133

考虑一个如下的场景：如图所示，两个Invoice的Service实现同一个接口，在Resource下调用两个服务的话，需要使用@Qualifier注解来确保注入的Bean是唯一的。

IBatchApprovalService.java

public interface IBatchApprovalService {
    ...
}

IInvoiceApprovalService.java

public interface IInvoiceApprovalService {
    ...
}

PaymentBatchApprovalService.java

@Service
public class PaymentBatchApprovalService implements IBatchApprovalService {
    ...
}

InvoiceDetailApprovalService.java

@Service("invoiceDetailApprovalService")
public class InvoiceDetailApprovalService implements IInvoiceApprovalService {
    ...
}

InvoiceHeaderApprovalService.java

@Service("invoiceHeaderApprovalService")
public class InvoiceHeaderApprovalService implements IInvoiceApprovalService {
    ...
}

PaymentApprovalResource.java

@Component
@Scope("request")
@Path("/payment_approval")
public class PaymentApprovalResource {
    ...
    @Inject
    @Qualifier("invoiceDetailApprovalService")
    private IInvoiceApprovalService invoiceDetailApprovalService;
    
    @Inject
    @Qualifier("invoiceHeaderApprovalService")
    private IInvoiceApprovalService invoiceHeaderApprovalService;

    @Inject
    private IBatchApprovalService paymentBatchApprovalService;
    
}