Spring源码(二) refresh () 方法
版本号：
SpringBoot 版本： 2.0.6.RELEASE
Spring 版本： 5.0.9.RELEASE
Spring源码(一) 如何阅读 Spring 源码
详情见： https://blog.csdn.net/sinat_32502451/article/details/140155044
ApplicationContext 和 BeanFactory
在阅读 refresh () 之前，可以简单了解下 ApplicationContext 和 BeanFactory。
详情见： https://blog.csdn.net/sinat_32502451/article/details/140247662
refresh () 方法
refresh()方法 负责初始化 ApplicationContext 容器。在调用refresh()方法之后，要么全部实例化，要么根本不实例化。
refresh()方法的路径： org.springframework.context.support.AbstractApplicationContext#refresh
public void refresh() throws BeansException, IllegalStateException {
synchronized (this.startupShutdownMonitor) {
//准备刷新
prepareRefresh();
//通知子类初始化/更新内部的bean factory
ConfigurableListableBeanFactory beanFactory = obtainFreshBeanFactory();
// 准备BeanFactory
prepareBeanFactory(beanFactory);
try {
// 后置处理。允许在BeanFactory初始化后进行修改，抽象类方法为空，可以继承后修改BeanFactory
postProcessBeanFactory(beanFactory);
// 调用上下文中注册为bean的工厂处理器。。
invokeBeanFactoryPostProcessors(beanFactory);
// 实例化并调用所有注册的Bean后置处理器
registerBeanPostProcessors(beanFactory);
// 为上下文初始化messageSource
initMessageSource();
// 为上下文初始化eventMulticaster
initApplicationEventMulticaster();
// 初始化其他特殊的beans
onRefresh();
// 检查监听器bean并注册
registerListeners();
// 实例化所有非懒加载的单例。这个方法，可以重点看看。
finishBeanFactoryInitialization(beanFactory);
// 发布相应的事件
finishRefresh();
}
catch (BeansException ex) {
if (logger.isWarnEnabled()) {
logger.warn("Exception encountered during context initialization - " +
"cancelling refresh attempt: " + ex);
}
// 销毁已创建的singleton
destroyBeans();
// 重置标记
cancelRefresh(ex);
// 向调用方传播异常
throw ex;
}
finally {
//重置Spring core中的缓存
resetCommonCaches();
}
}
}
BeanFactory
- BeanFactory 生成的具体路径：
org.springframework.context.support.AbstractApplicationContext#refresh ---->
org.springframework.context.support.AbstractApplicationContext#obtainFreshBeanFactory ---->
org.springframework.context.support.AbstractApplicationContext#refreshBeanFactory ---->
org.springframework.context.support.AbstractRefreshableApplicationContext#refreshBeanFactory ---->
org.springframework.context.support.AbstractRefreshableApplicationContext#createBeanFactory
- refreshBeanFactory () 方法：
@Override
protected final void refreshBeanFactory() throws BeansException {
if (hasBeanFactory()) {
destroyBeans();
closeBeanFactory();
}
try {
//重点看这一块代码
DefaultListableBeanFactory beanFactory = createBeanFactory();
beanFactory.setSerializationId(getId());
customizeBeanFactory(beanFactory);
loadBeanDefinitions(beanFactory);
synchronized (this.beanFactoryMonitor) {
this.beanFactory = beanFactory;
}
}
catch (IOException ex) {
throw new ApplicationContextException("I/O error parsing bean definition source for " + getDisplayName(), ex);
}
}
- createBeanFactory() 方法：
BeanFactory 是在这个方法生成的。
createBeanFactory() ： 为此上下文创建一个内部 BeanFactory。
// 为此上下文创建一个内部 BeanFactory
protected DefaultListableBeanFactory createBeanFactory() {
return new DefaultListableBeanFactory(getInternalParentBeanFactory());
}
- 设置 BeanFactory 的属性：
protected void prepareBeanFactory(ConfigurableListableBeanFactory beanFactory) {
// 告知内部bean工厂使用上下文的类加载器等
beanFactory.setBeanClassLoader(getClassLoader());
beanFactory.setBeanExpressionResolver(new StandardBeanExpressionResolver(beanFactory.getBeanClassLoader()));
beanFactory.addPropertyEditorRegistrar(new ResourceEditorRegistrar(this, getEnvironment()));
// 使用上下文回调配置bean工厂
beanFactory.addBeanPostProcessor(new ApplicationContextAwareProcessor(this));
beanFactory.ignoreDependencyInterface(EnvironmentAware.class);
beanFactory.ignoreDependencyInterface(EmbeddedValueResolverAware.class);
beanFactory.ignoreDependencyInterface(ResourceLoaderAware.class);
beanFactory.ignoreDependencyInterface(ApplicationEventPublisherAware.class);
beanFactory.ignoreDependencyInterface(MessageSourceAware.class);
beanFactory.ignoreDependencyInterface(ApplicationContextAware.class);
beanFactory.registerResolvableDependency(BeanFactory.class, beanFactory);
beanFactory.registerResolvableDependency(ResourceLoader.class, this);
beanFactory.registerResolvableDependency(ApplicationEventPublisher.class, this);
beanFactory.registerResolvableDependency(ApplicationContext.class, this);
beanFactory.addBeanPostProcessor(new ApplicationListenerDetector(this));
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()));
}
// 注册默认环境相关的bean
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());
}
}
