Question

我有懒惰初始化bean的代码：

@Component @Lazy
class Resource {...}

@Component @Lazy @CustomProcessor
class ResourceProcessorFoo{
    @Autowired
    public ResourceProcessor(Resource resource) {...}
}
@Component @Lazy @CustomProcessor
class ResourceProcessorBar{
    @Autowired
    public ResourceProcessor(Resource resource) {...}
}

初始化应用程序上下文后，没有此bean的实例。当bean资源由应用程序上下文创建时（例如，applicationContext.getBean（Resource.class）），没有@CustomProcessor实例标记bean。

在创建Resource bean时，需要使用@CustomProcessor创建bean。怎么做？

更新：找到一个丑陋的解决方案 - 使用空的自动装配器：

@Autowired
public void setProcessors(List<ResourceProcessor> processor){}

Bean BeanPostProcessor的另一个丑陋的解决方案（太神奇了！）

@Component
class CustomProcessor implements BeanPostProcessor{
    public postProcessBeforeInitialization(Object bean, String beanName) {
        if(bean instanceof Resource){
            applicationContext.getBeansWithAnnotation(CustomProcessor.class);
        }
    }
}

也许有更优雅的方式？

Answer 1

您必须创建一个标记界面，如CustomProcessor

public interface CustomProcessor{

}

以后每个ResourceProcessor必须在接口

之上实现

@Component @Lazy 
class ResourceProcessorFoo implements CustomProcessor{
    @Autowired
    public ResourceProcessor(Resource resource) {...}
}
@Component @Lazy 
class ResourceProcessorBar implements CustomProcessor{
    @Autowired
    public ResourceProcessor(Resource resource) {...}
}

资源必须实现ApplicationContextAware

@Component
@Lazy
public class Resource implements ApplicationContextAware{

    private ApplicationContext applicationContext;

    @PostConstruct
    public void post(){
        applicationContext.getBeansOfType(CustomProcessor.class);
    }

    public void setApplicationContext(ApplicationContext applicationContext)throws BeansException {
        this.applicationContext = applicationContext;   
    }

}

当引用Resource bean时，启动postconstruct，初始化实现CustomProcessor接口的所有bean。

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1 个答案: