spring对象加载过程测试

左手的ㄟ右手 2022-06-16 13:07 171阅读 0赞

测试spring对象加载过程  
首先new 一个AnnotationConfigApplicationContext的实例  
然后在这个实例上使用register方法注册bean

context.register(Config1.class, BeanConfig1.class);

准备使用spring的注解实例化的这两个类  
然后在上面注册之后调用刷新方法

context.refresh();

刷新过程如下  
AbstractApplicationContext

synchronized (this.startupShutdownMonitor) {
                // Prepare this context for refreshing.
                //这个位置准备环境和property配置资源
                //AnnotationConfigApplicationContext在这子类中会清空扫描包的缓存
                prepareRefresh();
    
                // Tell the subclass to refresh the internal bean factory.
                //指明要刷新的子工厂
                ConfigurableListableBeanFactory beanFactory = obtainFreshBeanFactory();
    
                // Prepare the bean factory for use in this context.
                //准备刷新工厂
                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;
                }
            }

刷新工厂

protected void prepareBeanFactory(ConfigurableListableBeanFactory beanFactory) {
            // Tell the internal bean factory to use the context's class loader etc.
            beanFactory.setBeanClassLoader(getClassLoader());
            beanFactory.setBeanExpressionResolver(new StandardBeanExpressionResolver(beanFactory.getBeanClassLoader()));
            beanFactory.addPropertyEditorRegistrar(new ResourceEditorRegistrar(this, getEnvironment()));
    
            // Configure the bean factory with context callbacks.
            beanFactory.addBeanPostProcessor(new ApplicationContextAwareProcessor(this));
            beanFactory.ignoreDependencyInterface(ResourceLoaderAware.class);
            beanFactory.ignoreDependencyInterface(ApplicationEventPublisherAware.class);
            beanFactory.ignoreDependencyInterface(MessageSourceAware.class);
            beanFactory.ignoreDependencyInterface(ApplicationContextAware.class);
            beanFactory.ignoreDependencyInterface(EnvironmentAware.class);
    
            // BeanFactory interface not registered as resolvable type in a plain factory.
            // MessageSource registered (and found for autowiring) as a bean.
            beanFactory.registerResolvableDependency(BeanFactory.class, beanFactory);
            beanFactory.registerResolvableDependency(ResourceLoader.class, this);
            beanFactory.registerResolvableDependency(ApplicationEventPublisher.class, this);
            beanFactory.registerResolvableDependency(ApplicationContext.class, this);
    
            // Detect a LoadTimeWeaver and prepare for weaving, if found.
            if (beanFactory.containsBean(LOAD_TIME_WEAVER_BEAN_NAME)) {
                beanFactory.addBeanPostProcessor(new LoadTimeWeaverAwareProcessor(beanFactory));
                // Set a temporary ClassLoader for type matching.
                beanFactory.setTempClassLoader(new ContextTypeMatchClassLoader(beanFactory.getBeanClassLoader()));
            }
    
            // Register default environment beans.
            if (!beanFactory.containsLocalBean(ENVIRONMENT_BEAN_NAME)) {
                beanFactory.registerSingleton(ENVIRONMENT_BEAN_NAME, getEnvironment());
            }
            if (!beanFactory.containsLocalBean(SYSTEM_PROPERTIES_BEAN_NAME)) {
                beanFactory.registerSingleton(SYSTEM_PROPERTIES_BEAN_NAME, getEnvironment().getSystemProperties());
            }
            if (!beanFactory.containsLocalBean(SYSTEM_ENVIRONMENT_BEAN_NAME)) {
                beanFactory.registerSingleton(SYSTEM_ENVIRONMENT_BEAN_NAME, getEnvironment().getSystemEnvironment());
            }
        }