Spring5源码 - 07 Spring Bean 生命周期流程源码解读02

Bertha 。 2022-12-08 15:42 159阅读 0赞

### 文章目录 ###

*  Pre
 *  通俗流程
 *  finishBeanFactoryInitialization

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# Pre #

[Spring5源码 - 06 Spring Bean 生命周期流程 概述 01][Spring5_ - 06 Spring Bean _ _ 01]

接上文

# 通俗流程 #

下面说个比较常见的主干流程

1.  实例化Bean对象，这个时候Bean的对象是非常低级的，基本不能够使用，因为连最基本的属性都没有设置，可以理解为  
    连Autowired注解都是没有解析的；
2.  填充属性，当做完这一步，Bean对象基本是完整的了，可以理解为Autowired注解已经解析完毕，依赖注入完成了；
3.  如果Bean实现了BeanNameAware接口，则调用setBeanName方法；
4.  如果Bean实现了BeanClassLoaderAware接口，则调用setBeanClassLoader方法；
5.  如果Bean实现了BeanFactoryAware接口，则调用setBeanFactory方法；
6.  调用BeanPostProcessor的postProcessBeforeInitialization方法；
7.  如果Bean实现了InitializingBean接口，调用afterPropertiesSet方法；
8.  如果Bean定义了init-method方法，则调用Bean的init-method方法；
9.  调用BeanPostProcessor的postProcessAfterInitialization方法；当进行到这一步，Bean已经被准备就绪了，一直停留在应用的  
    上下文中，直到被销毁；
10. 如果应用的上下文被销毁了，如果Bean实现了DisposableBean接口，则调用destroy方法，如果Bean定义了destory-method  
    声明了销毁方法也会被调用。

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# finishBeanFactoryInitialization #

**完成Bean的初始化**

/** * Finish the initialization of this context's bean factory, * initializing all remaining singleton beans. */
    	protected void finishBeanFactoryInitialization(ConfigurableListableBeanFactory beanFactory) { 
    		// bean工厂创建类型转化器 Convert
    		/** * public class String2DateConversionService implements Converter<String,Date> { public Date convert(String source) { SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss"); try { return sdf.parse(source); } catch (ParseException e) { return null; } } } @Bean public ConversionServiceFactoryBean conversionService() { ConversionServiceFactoryBean factoryBean = new ConversionServiceFactoryBean(); Set<Converter> converterSet = new HashSet<Converter>(); converterSet.add(new String2DateConversionService()); factoryBean.setConverters(converterSet); return factoryBean; } ConversionServiceFactoryBean conversionServiceFactoryBean = (ConversionServiceFactoryBean) ctx.getBean(ConversionServiceFactoryBean.class); conversionServiceFactoryBean.getObject().convert("2019-06-03 12:00:00",Date.class) */
    		if (beanFactory.containsBean(CONVERSION_SERVICE_BEAN_NAME) &&
    				beanFactory.isTypeMatch(CONVERSION_SERVICE_BEAN_NAME, ConversionService.class)) { 
    			beanFactory.setConversionService(
    					beanFactory.getBean(CONVERSION_SERVICE_BEAN_NAME, ConversionService.class));
    		}
    
    		/** * public class MainConfig implements EmbeddedValueResolverAware{ * * public void setEmbeddedValueResolver(StringValueResolver resolver) { this.jdbcUrl = resolver.resolveStringValue("${ds.jdbcUrl}"); this.classDriver = resolver.resolveStringValue("${ds.classDriver}"); } } */
    		if (!beanFactory.hasEmbeddedValueResolver()) { 
    			beanFactory.addEmbeddedValueResolver(strVal -> getEnvironment().resolvePlaceholders(strVal));
    		}
    
    		// 处理aspectj
    		String[] weaverAwareNames = beanFactory.getBeanNamesForType(LoadTimeWeaverAware.class, false, false);
    		for (String weaverAwareName : weaverAwareNames) { 
    			getBean(weaverAwareName);
    		}
    
    		// Stop using the temporary ClassLoader for type matching.
    		beanFactory.setTempClassLoader(null);
    
    		//冻结所有的 bean 定义 ， 说明注册的 bean 定义将不被修改或任何进一步的处理
    		beanFactory.freezeConfiguration();
    
    		//实例化剩余的单实例bean
    		beanFactory.preInstantiateSingletons();
    	}

继续

beanFactory.preInstantiateSingletons();

@Override
    	public void preInstantiateSingletons() throws BeansException { 
    		if (logger.isDebugEnabled()) { 
    			logger.debug("Pre-instantiating singletons in " + this);
    		}
    
    		//获取我们容器中所有bean定义的名称
    		List<String> beanNames = new ArrayList<>(this.beanDefinitionNames);
    
    		//循环我们所有的bean定义名称
    		for (String beanName : beanNames) { 
    			//合并我们的bean定义
    			RootBeanDefinition bd = getMergedLocalBeanDefinition(beanName);
    			/** * 根据bean定义判断是不是抽象的&& 不是单例的 &&不是懒加载的 */
    			if (!bd.isAbstract() && bd.isSingleton() && !bd.isLazyInit()) { 
    				//是不是工厂bean
    				if (isFactoryBean(beanName)) { 
    					//是的话 给beanName+前缀&符号
    					Object bean = getBean(FACTORY_BEAN_PREFIX + beanName);
    					if (bean instanceof FactoryBean) { 
    						final FactoryBean<?> factory = (FactoryBean<?>) bean;
    						boolean isEagerInit;
    						if (System.getSecurityManager() != null && factory instanceof SmartFactoryBean) { 
    							isEagerInit = AccessController.doPrivileged((PrivilegedAction<Boolean>)
    											((SmartFactoryBean<?>) factory)::isEagerInit,
    									getAccessControlContext());
    						}
    						else { 
    							isEagerInit = (factory instanceof SmartFactoryBean &&
    									((SmartFactoryBean<?>) factory).isEagerInit());
    						}
    						//调用真正的getBean的流程
    						if (isEagerInit) { 
    							getBean(beanName);
    						}
    					}
    				}
    				else { //非工厂Bean 就是普通的bean
    					getBean(beanName);
    				}
    			}
    		}
    
    		//或有的bean的名称 ...........到这里所有的单实例的bean已经记载到单实例bean到缓存中
    		for (String beanName : beanNames) { 
    			//从单例缓存池中获取所有的对象
    			Object singletonInstance = getSingleton(beanName);
    			//判断当前的bean是否实现了SmartInitializingSingleton接口
    			if (singletonInstance instanceof SmartInitializingSingleton) { 
    				final SmartInitializingSingleton smartSingleton = (SmartInitializingSingleton) singletonInstance;
    				if (System.getSecurityManager() != null) { 
    					AccessController.doPrivileged((PrivilegedAction<Object>) () -> { 
    						smartSingleton.afterSingletonsInstantiated();
    						return null;
    					}, getAccessControlContext());
    				}
    				else { 
    					//触发实例化之后的方法afterSingletonsInstantiated
    					smartSingleton.afterSingletonsInstantiated();
    				}
    			}
    		}
    	}

重点方法肯定是 `getBean(beanName);`咯

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[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3lhbmdzaGFuZ3dlaQ_size_16_color_FFFFFF_t_70_pic_center]: /images/20221123/084e4f4ba1e74164986f6674cafbb3bd.png
[Spring5_ - 06 Spring Bean _ _ 01]: https://artisan.blog.csdn.net/article/details/108683438
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