Spring 容器初始化源码跟读refresh04

最新推荐文章于 2025-09-09 09:10:31 发布

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最新推荐文章于 2025-09-09 09:10:31 发布

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文章标签： java

原文链接：http://www.cnblogs.com/aqu415/p/7822654.html

本文详细解析了Spring框架中的BeanFactoryPostProcessor及其子接口BeanDefinitionRegistryPostProcessor的工作原理与应用方式。通过实例展示了如何利用这些接口来定制化BeanFactory的行为。

接下来是

// Allows post-processing of the bean factory in context subclasses.
postProcessBeanFactory(beanFactory);

该方法是一个空方法

接下来是protected void invokeBeanFactoryPostProcessors(ConfigurableListableBeanFactory beanFactory) 方法

protected void invokeBeanFactoryPostProcessors(ConfigurableListableBeanFactory beanFactory) {
        // Invoke BeanDefinitionRegistryPostProcessors first, if any.
        Set<String> processedBeans = new HashSet<String>();
        if (beanFactory instanceof BeanDefinitionRegistry) {
            BeanDefinitionRegistry registry = (BeanDefinitionRegistry) beanFactory;
            List<BeanFactoryPostProcessor> regularPostProcessors = new LinkedList<BeanFactoryPostProcessor>();
            List<BeanDefinitionRegistryPostProcessor> registryPostProcessors =
                    new LinkedList<BeanDefinitionRegistryPostProcessor>();
            for (BeanFactoryPostProcessor postProcessor : getBeanFactoryPostProcessors()) {
                if (postProcessor instanceof BeanDefinitionRegistryPostProcessor) {
                    BeanDefinitionRegistryPostProcessor registryPostProcessor =
                            (BeanDefinitionRegistryPostProcessor) postProcessor;
                    registryPostProcessor.postProcessBeanDefinitionRegistry(registry);
                    registryPostProcessors.add(registryPostProcessor);
                }
                else {
                    regularPostProcessors.add(postProcessor);
                }
            }
            Map<String, BeanDefinitionRegistryPostProcessor> beanMap =
                    beanFactory.getBeansOfType(BeanDefinitionRegistryPostProcessor.class, true, false);
            List<BeanDefinitionRegistryPostProcessor> registryPostProcessorBeans =
                    new ArrayList<BeanDefinitionRegistryPostProcessor>(beanMap.values());
            OrderComparator.sort(registryPostProcessorBeans);
            for (BeanDefinitionRegistryPostProcessor postProcessor : registryPostProcessorBeans) {
                postProcessor.postProcessBeanDefinitionRegistry(registry);
            }
            invokeBeanFactoryPostProcessors(registryPostProcessors, beanFactory);
            invokeBeanFactoryPostProcessors(registryPostProcessorBeans, beanFactory);
            invokeBeanFactoryPostProcessors(regularPostProcessors, beanFactory);
            processedBeans.addAll(beanMap.keySet());
        }
        else {
            // Invoke factory processors registered with the context instance.
            invokeBeanFactoryPostProcessors(getBeanFactoryPostProcessors(), beanFactory);
        }

        // Do not initialize FactoryBeans here: We need to leave all regular beans
        // uninitialized to let the bean factory post-processors apply to them!
        String[] postProcessorNames =
                beanFactory.getBeanNamesForType(BeanFactoryPostProcessor.class, true, false);

        // Separate between BeanFactoryPostProcessors that implement PriorityOrdered,
        // Ordered, and the rest.
        List<BeanFactoryPostProcessor> priorityOrderedPostProcessors = new ArrayList<BeanFactoryPostProcessor>();
        List<String> orderedPostProcessorNames = new ArrayList<String>();
        List<String> nonOrderedPostProcessorNames = new ArrayList<String>();
        for (String ppName : postProcessorNames) {
            if (processedBeans.contains(ppName)) {
                // skip - already processed in first phase above
            }
            else if (isTypeMatch(ppName, PriorityOrdered.class)) {
                priorityOrderedPostProcessors.add(beanFactory.getBean(ppName, BeanFactoryPostProcessor.class));
            }
            else if (isTypeMatch(ppName, Ordered.class)) {
                orderedPostProcessorNames.add(ppName);
            }
            else {
                nonOrderedPostProcessorNames.add(ppName);
            }
        }

        // First, invoke the BeanFactoryPostProcessors that implement PriorityOrdered.
        OrderComparator.sort(priorityOrderedPostProcessors);
        invokeBeanFactoryPostProcessors(priorityOrderedPostProcessors, beanFactory);

        // Next, invoke the BeanFactoryPostProcessors that implement Ordered.
        List<BeanFactoryPostProcessor> orderedPostProcessors = new ArrayList<BeanFactoryPostProcessor>();
        for (String postProcessorName : orderedPostProcessorNames) {
            orderedPostProcessors.add(getBean(postProcessorName, BeanFactoryPostProcessor.class));
        }
        OrderComparator.sort(orderedPostProcessors);
        invokeBeanFactoryPostProcessors(orderedPostProcessors, beanFactory);

        // Finally, invoke all other BeanFactoryPostProcessors.
        List<BeanFactoryPostProcessor> nonOrderedPostProcessors = new ArrayList<BeanFactoryPostProcessor>();
        for (String postProcessorName : nonOrderedPostProcessorNames) {
            nonOrderedPostProcessors.add(getBean(postProcessorName, BeanFactoryPostProcessor.class));
        }
        invokeBeanFactoryPostProcessors(nonOrderedPostProcessors, beanFactory);
    }

该方法主要功能是把定义的 BeanFactoryPostProcessor 、BeanDefinitionRegistryPostProcessor的接口实现分离出来，然后调用postProcessBeanFactory方法修改beanFactory或者BeanDefinition内部结构

如下两个例子：

package springsrc.postProcessor;

import org.springframework.beans.BeansException;
import org.springframework.beans.factory.config.ConfigurableListableBeanFactory;
import org.springframework.beans.factory.support.BeanDefinitionRegistry;
import org.springframework.beans.factory.support.BeanDefinitionRegistryPostProcessor;

public class TT implements BeanDefinitionRegistryPostProcessor {

    @Override
    public void postProcessBeanFactory(
            ConfigurableListableBeanFactory beanFactory) throws BeansException {
        System.out.println("postProcessBeanFactory****");
    }

    @Override
    public void postProcessBeanDefinitionRegistry(
            BeanDefinitionRegistry registry) throws BeansException {
        
        System.out.println("postProcessBeanDefinitionRegistry***&&&&");
    }

}

package springsrc.postProcessor;

import org.springframework.beans.BeansException;
import org.springframework.beans.factory.config.BeanFactoryPostProcessor;
import org.springframework.beans.factory.config.ConfigurableListableBeanFactory;

public class TTT implements BeanFactoryPostProcessor {

    @Override
    public void postProcessBeanFactory(
            ConfigurableListableBeanFactory beanFactory) throws BeansException {
        System.out.println("postProcessBeanFactory-----");

    }

}

并将这两个类配置在配置文件中，则该两个类的方法就会被自动调用，进而对beanFactory 或者所有的 BeanDefinition 进行处理

<bean class="springsrc.postProcessor.T"></bean>
<bean class="springsrc.postProcessor.TT"></bean>

转载于:https://www.cnblogs.com/aqu415/p/7822654.html