spring源码解析之ioc-registerBeanPostProcessors

╰+哭是因爲堅強的太久メ 2022-12-27 07:19 87阅读 0赞

继续往下走

//往下看
    registerBeanPostProcessors(beanFactory);

注册beanPostProcessors

protected void registerBeanPostProcessors(ConfigurableListableBeanFactory beanFactory) { 
    		//继续往下看
    		PostProcessorRegistrationDelegate.registerBeanPostProcessors(beanFactory, this);
    	}

public static void registerBeanPostProcessors(
    			ConfigurableListableBeanFactory beanFactory, AbstractApplicationContext applicationContext) { 
    
    		//同样的配方 根据类型获取beanName BeanPostProcessor类型
    		String[] postProcessorNames = beanFactory.getBeanNamesForType(BeanPostProcessor.class, true, false);
    
    		int beanProcessorTargetCount = beanFactory.getBeanPostProcessorCount() + 1 + postProcessorNames.length;
    		beanFactory.addBeanPostProcessor(new BeanPostProcessorChecker(beanFactory, beanProcessorTargetCount));
    
    		//跟上一篇分析的一模一样 根据优先级获取bean 执行对应的方法~~~
    		
    		List<BeanPostProcessor> priorityOrderedPostProcessors = new ArrayList<>();
    		List<BeanPostProcessor> internalPostProcessors = new ArrayList<>();
    		List<String> orderedPostProcessorNames = new ArrayList<>();
    		List<String> nonOrderedPostProcessorNames = new ArrayList<>();
    		for (String ppName : postProcessorNames) { 
    			if (beanFactory.isTypeMatch(ppName, PriorityOrdered.class)) { 
    				BeanPostProcessor pp = beanFactory.getBean(ppName, BeanPostProcessor.class);
    				priorityOrderedPostProcessors.add(pp);
    				if (pp instanceof MergedBeanDefinitionPostProcessor) { 
    					internalPostProcessors.add(pp);
    				}
    			}
    			else if (beanFactory.isTypeMatch(ppName, Ordered.class)) { 
    				orderedPostProcessorNames.add(ppName);
    			}
    			else { 
    				nonOrderedPostProcessorNames.add(ppName);
    			}
    		}
    		//排序
    		sortPostProcessors(priorityOrderedPostProcessors, beanFactory);
    		//注册进beanFactory
    		registerBeanPostProcessors(beanFactory, priorityOrderedPostProcessors);
    
    		List<BeanPostProcessor> orderedPostProcessors = new ArrayList<>(orderedPostProcessorNames.size());
    		for (String ppName : orderedPostProcessorNames) { 
    			BeanPostProcessor pp = beanFactory.getBean(ppName, BeanPostProcessor.class);
    			orderedPostProcessors.add(pp);
    			if (pp instanceof MergedBeanDefinitionPostProcessor) { 
    				internalPostProcessors.add(pp);
    			}
    		}
    		sortPostProcessors(orderedPostProcessors, beanFactory);
    		registerBeanPostProcessors(beanFactory, orderedPostProcessors);
    
    		// Now, register all regular BeanPostProcessors.
    		List<BeanPostProcessor> nonOrderedPostProcessors = new ArrayList<>(nonOrderedPostProcessorNames.size());
    		for (String ppName : nonOrderedPostProcessorNames) { 
    			BeanPostProcessor pp = beanFactory.getBean(ppName, BeanPostProcessor.class);
    			nonOrderedPostProcessors.add(pp);
    			if (pp instanceof MergedBeanDefinitionPostProcessor) { 
    				internalPostProcessors.add(pp);
    			}
    		}
    		registerBeanPostProcessors(beanFactory, nonOrderedPostProcessors);
    
    		// Finally, re-register all internal BeanPostProcessors.
    		sortPostProcessors(internalPostProcessors, beanFactory);
    		registerBeanPostProcessors(beanFactory, internalPostProcessors);
    
    		// Re-register post-processor for detecting inner beans as ApplicationListeners,
    		// moving it to the end of the processor chain (for picking up proxies etc).
    		beanFactory.addBeanPostProcessor(new ApplicationListenerDetector(applicationContext));
    	}

这一块跟前面处理beanFacrotyPostProcessor有一个区别：

beanFactoryPostProcessor只是执行了相关的接口的方法，但不会保存这种类型的bean，也就是说这个bean用了之后就抛弃了

void postProcessBeanDefinitionRegistry(BeanDefinitionRegistry var1) throws BeansException;
        void postProcessBeanFactory(ConfigurableListableBeanFactory var1) throws BeansException;

beanPostProcessor 只是将这类bean单独保存了起来，在创建完bean之后，设置完bean的属性之后，才会执行相关接口的方法

在说的仔细一点：beanFactory会将所有的实现了beanPostProcessor的bean在这里创建出来，然后保存起来。  
之后在创建了其他的bean之后，设置了bean的属性，然后回实例化这个bean  
1、遍历保存起来的beanPostProcessor类型的bean，  
2、然后执行postProcessBeforeInitialization方法，

3、接着执行正在处理的bean的initMethod()  
如果bean实现了InitializingBean接口，那么就会在initMethod中调用afterPropertiesSet方法

4、最后执行postProcessAfterInitialization 方法

registerBeanPostProcessors(beanFactory, (List)priorityOrderedPostProcessors);

beanFacrotyPostProcessor与beanPostProcessor 相同点：  
在处理这一块的时候，都会创建好这个bean，然后才会做对应的操作  
也就是说这类型的bean创建更早

~~关于spring ioc 对于bean的创建时机与管理还是蛮复杂的