java – 在Spring 3中定制Autowire候选bean
发布时间:2020-12-14 17:43:09 所属栏目:Java 来源:网络整理
导读:说我有一个服务接口ServiceInterface和一些实现它的组件的以下结构:ProductAService和ProductBService我还有一个RequestContext bean,它有一个限定属性,表示我们现在正在处理ProductA或ProductB.那么如何可以自动注入自动装配或其他注释正确的实现(ProductA
说我有一个服务接口ServiceInterface和一些实现它的组件的以下结构:ProductAService和ProductBService我还有一个RequestContext bean,它有一个限定属性,表示我们现在正在处理ProductA或ProductB.那么如何可以自动注入自动装配或其他注释正确的实现(ProductAService或ProductBService)到某些需要它的服务(ServiceThatNeedsServiceInterface下面).
public interface ServiceInterface { void someMethod(); } @Component(name="ProductAService") public class ProductAService implements ServiceInterface { @Override public void someMethod() { System.out.println("Hello,A Service"); } } @Component(name="ProductBService") public class ProductBService implements ServiceInterface { @Override public void someMethod() { System.out.println("Hello,B Service"); } } @Component public class ServiceThatNeedsServiceInterface { // What to do here??? @Autowired ServiceInterface service; public void useService() { service.someMethod(); } } @Component @Scope( value = WebApplicationContext.SCOPE_REQUEST ) public class RequestContext { String getSomeQualifierProperty(); } 解决方法
Spring Source在版本1.1.4中创建了
ServiceLocatorFactoryBean时引用了您的问题.为了使用它,您需要添加类似于下面的界面:
public interface ServiceLocator { //ServiceInterface service name is the one //set by @Component public ServiceInterface lookup(String serviceName); } 您需要将以下代码片段添加到您的applicationContext.xml中 <bean id="serviceLocatorFactoryBean" class="org.springframework.beans.factory.config.ServiceLocatorFactoryBean"> <property name="serviceLocatorInterface" value="org.haim.springframwork.stackoverflow.ServiceLocator" /> </bean> 现在您的ServiceThatNeedsServiceInterface将类似于以下内容: @Component public class ServiceThatNeedsServiceInterface { // What to do here??? // @Autowired // ServiceInterface service; /* * ServiceLocator lookup returns the desired implementation * (ProductAService or ProductBService) */ @Autowired private ServiceLocator serviceLocatorFactoryBean; //Let’s assume we got this from the web request public RequestContext context; public void useService() { ServiceInterface service = serviceLocatorFactoryBean.lookup(context.getQualifier()); service.someMethod(); } } ServiceLocatorFactoryBean将根据RequestContext限定符返回所需的服务. @RunWith(SpringJUnit4ClassRunner.class) @ContextConfiguration(locations = { "classpath:META-INF/spring/applicationContext.xml" }) public class ServiceThatNeedsServiceInterfaceTest { @Autowired ServiceThatNeedsServiceInterface serviceThatNeedsServiceInterface; @Test public void testUseService() { //As we are not running from a web container //so we set the context directly to the service RequestContext context = new RequestContext(); context.setQualifier("ProductAService"); serviceThatNeedsServiceInterface.context = context; serviceThatNeedsServiceInterface.useService(); context.setQualifier("ProductBService"); serviceThatNeedsServiceInterface.context = context; serviceThatNeedsServiceInterface.useService(); } } 显示控制台 一句警告. API文档说明 我不明白为什么会导致一个问题.在我的代码中,它返回相同的服务在两个序列调用serviceThatNeedsServiceInterface.useService(); 您可以在GitHub中找到我示例的源代码 (编辑:李大同) 【声明】本站内容均来自网络,其相关言论仅代表作者个人观点,不代表本站立场。若无意侵犯到您的权利,请及时与联系站长删除相关内容! |