Spring的refresh()方法调用过程

╰+攻爆jí腚メ 2024-04-18 13:38 56阅读 0赞

Spring的refresh()方法调用过程  
refresh()是Spring中比较核心的方法，Spring所有的初始化都在这个方法中完成  
具体代码如下

public void refresh() throws BeansException, IllegalStateException { 
            synchronized (this.startupShutdownMonitor) { 
                // Prepare this context for refreshing.
                prepareRefresh();
    
                // Tell the subclass to refresh the internal bean factory.
                ConfigurableListableBeanFactory beanFactory = obtainFreshBeanFactory();
    
                // Prepare the bean factory for use in this context.
                prepareBeanFactory(beanFactory);
    
                try { 
                    // Allows post-processing of the bean factory in context subclasses.
                    postProcessBeanFactory(beanFactory);
    
                    // Invoke factory processors registered as beans in the context.
                    invokeBeanFactoryPostProcessors(beanFactory);
    
                    // Register bean processors that intercept bean creation.
                    registerBeanPostProcessors(beanFactory);
    
                    // Initialize message source for this context.
                    initMessageSource();
    
                    // Initialize event multicaster for this context.
                    initApplicationEventMulticaster();
    
                    // Initialize other special beans in specific context subclasses.
                    onRefresh();
    
                    // Check for listener beans and register them.
                    registerListeners();
    
                    // Instantiate all remaining (non-lazy-init) singletons.
                    finishBeanFactoryInitialization(beanFactory);
    
                    // Last step: publish corresponding event.
                    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;
                }
            }
        }

Spring中refresh调用过程  
//准备工作包括设置启动时间，是否激活标识位，初始化属性源(property source)配置

prepareRefresh();

//创建beanFactory（过程是根据xml为每个bean生成BeanDefinition并注册到生成的beanFactory）

ConfigurableListableBeanFactory beanFactory = obtainFreshBeanFactory();

//准备创建好的beanFactory（给beanFactory设置ClassLoader，设置SpEL表达式解析器，设置类型转化器【能将xml String类型转成相应对象】，增加内置ApplicationContextAwareProcessor对象，忽略各种Aware对象，注册各种内置的对账对象【BeanFactory，ApplicationContext】等，注册AOP相关的一些东西，注册环境相关的一些bean

prepareBeanFactory(ConfigurableListableBeanFactory beanFactory)

//实例化并调用BeanFactory中扩展了BeanFactoryPostProcessor的Bean的postProcessBeanFactory方法

invokeBeanFactoryPostProcessors(beanFactory);

//实例化和注册beanFactory中扩展了BeanPostProcessor的bean

registerBeanPostProcessors(beanFactory)方法;

//实例化，注册和设置国际化工具类MessageSource

initMessageSource();

//实例化，注册和设置消息广播类（如果没有自己定义使用默认的SimpleApplicationEventMulticaster实现，此广播使用同步的通知方式）

initApplicationEventMulticaster();

//设置样式工具ThemeSource

onRefresh();

//添加用户定义的消息接收器到上面设置的消息广播ApplicationEventMulticaster