[Source code analysis] DEBUG Spring IOC source code

SpringIOC

声明： 此博客仅记录本人DUBUG源码步骤

Rough diagram:

1. Load the xml file

​

setConfigLocations method

2. Call the Refresh method

Refresh method

The prepare* methods are all preparations!

@Override
	public void refresh() throws BeansException, IllegalStateException {
    
    
		synchronized (this.startupShutdownMonitor) {
    
    
			// Prepare this context for refreshing.
         	// 准备工作
			prepareRefresh();

			// Tell the subclass to refresh the internal bean factory.
            // 实例化BeanFactory
			ConfigurableListableBeanFactory beanFactory = obtainFreshBeanFactory();

			// Prepare the bean factory for use in this context.
            // 准备工作，设置或忽略Factory中的一些对箱子
			prepareBeanFactory(beanFactory);

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

				// Invoke factory processors registered as beans in the context.
                // 实例化并执行BeanFactoryPostProcessors
				invokeBeanFactoryPostProcessors(beanFactory);

				// Register bean processors that intercept bean creation.
                // 注册BeanPostProcessors
				registerBeanPostProcessors(beanFactory);

				// Initialize message source for this context.
                // 国际化处理
				initMessageSource();

				// Initialize event multicaster for this context.
                // 初始化一个广播器
				initApplicationEventMulticaster();

				// Initialize other special beans in specific context subclasses.
                // 扩展
				onRefresh();

				// Check for listener beans and register them.
                // 注册监听器
				registerListeners();

				// Instantiate all remaining (non-lazy-init) singletons.
                // 实例化Bean
				finishBeanFactoryInitialization(beanFactory);

				// Last step: publish corresponding event.
                // 刷新
				finishRefresh();
			}

			catch (BeansException ex) {
    
    
				logger.warn("Exception encountered during context initialization - cancelling refresh attempt", ex);

				// Destroy already created singletons to avoid dangling resources.
				destroyBeans();

				// Reset 'active' flag.
				cancelRefresh(ex);

				// Propagate exception to caller.
				throw ex;
			}
		}
	}

prepareRefresh() method

ConfigurableListableBeanFactory beanFactory = obtainFreshBeanFactory(); // 创建BeanFactory对象

refreshBeanFactory method

prepareBeanFactory(beanFactory);

The standard context features of the configuration factory, such as the class loader and post processor of the context.

postProcessBeanFactory(beanFactory);

Subclass extension

invokeBeanFactoryPostProcessors(beanFactory)

Instantiate and execute BeanFactoryPostProcessors!

registerBeanPostProcessors(beanFactory)

Register BeanPostProcessor bean

initMessageSource();

International processing!

initApplicationEventMulticaster()

Initialize a broadcaster!

registerListeners()

Register the listener!

finishBeanFactoryInitialization(beanFactory);

Instantiate bean

@Override
	public void preInstantiateSingletons() throws BeansException {
    
    
		if (this.logger.isDebugEnabled()) {
    
    
			this.logger.debug("Pre-instantiating singletons in " + this);
		}

		// Iterate over a copy to allow for init methods which in turn register new bean definitions.
		// While this may not be part of the regular factory bootstrap, it does otherwise work fine.
		List<String> beanNames = new ArrayList<String>(this.beanDefinitionNames);

		// Trigger initialization of all non-lazy singleton beans...
		for (String beanName : beanNames) {
    
    
			RootBeanDefinition bd = getMergedLocalBeanDefinition(beanName);
			if (!bd.isAbstract() && bd.isSingleton() && !bd.isLazyInit()) {
    
    
				if (isFactoryBean(beanName)) {
    
    
					final FactoryBean<?> factory = (FactoryBean<?>) getBean(FACTORY_BEAN_PREFIX + beanName);
					boolean isEagerInit;
					if (System.getSecurityManager() != null && factory instanceof SmartFactoryBean) {
    
    
						isEagerInit = AccessController.doPrivileged(new PrivilegedAction<Boolean>() {
    
    
							@Override
							public Boolean run() {
    
    
								return ((SmartFactoryBean<?>) factory).isEagerInit();
							}
						}, getAccessControlContext());
					}
					else {
    
    
						isEagerInit = (factory instanceof SmartFactoryBean &&
								((SmartFactoryBean<?>) factory).isEagerInit());
					}
					if (isEagerInit) {
    
    
						getBean(beanName);
					}
				}
				else {
    
    
					getBean(beanName);
				}
			}
		}

In the doGetBean method

In createBean method

In the createBeanInstance method, Bean objects are created through a series of reflection logic

Use attribute values ​​to populate Bean instances in a given BeanWrapper

At this point, the Bean is created and instantiated!

finishRefresh()

To complete the refresh of this context, call the onRefresh() method of LifecycleProcessor and publish

Attachment: Bean's life cycle