本篇内容介绍了“java Spring Bean Container的启动加载初始化流程是什么”的有关知识，在实际案例的操作过程中，不少人都会遇到这样的困境，接下来就让小编带领大家学习一下如何处理这些情况吧！希望大家仔细阅读，能够学有所成！
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Spring对beanFactory的处理
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) {
if (logger.isWarnEnabled()) {
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;
}finally {
// Reset common introspection caches in Spring's core, since we
// might not ever need metadata for singleton beans anymore...
resetCommonCaches();
}
}
}prepareRefresh()这里不用细看就是自身进行些配置和参数校验什么的
obtainFreshBeanFactory()加载NameSpacehandler
使用各个NameSpcaceHandler生成Beandifinitions并注册到beanfactory里面去
NameSpaceHandler加载过程的解析已经写过就不再写了； 参看前面的文章
NamespaceHandlerSupport
//返回也没用,应该定义为void的，parserContext的registry就是beanFactory
public BeanDefinition parse(Element element, ParserContext parserContext) {
//获取具体的BeanDefinitionParser,比如说ComponentScanBeanDefinitionParser
return findParserForElement(element, parserContext).parse(element, parserContext);
}ComponentScanBeanDefinitionParser 这是个样板例子,一看就知道怎么回事
public BeanDefinition parse(Element element, ParserContext parserContext) {
String basePackage = element.getAttribute(BASE_PACKAGE_ATTRIBUTE);//获取basepackage设定的包名
basePackage = parserContext.getReaderContext().getEnvironment().resolvePlaceholders(basePackage);//有可能使用了$
String[] basePackages = StringUtils.tokenizeToStringArray(basePackage,ConfigurableApplicationContext.CONFIG_LOCATION_DELIMITERS);//解析出全部的package
// Actually scan for bean definitions and register them.
ClassPathBeanDefinitionScanner scanner = configureScanner(parserContext, element);//配置扫描器
Set beanDefinitions = scanner.doScan(basePackages);//扫包
registerComponents(parserContext.getReaderContext(), beanDefinitions, element);//向beanFactory注册
return null;
} 主要是完成BeanFactoryPostProcessors的初始化
protected void prepareBeanFactory(ConfigurableListableBeanFactory beanFactory) {
...
//注意这是LTW,加载时代码织入进行增强AOP
if (beanFactory.containsBean(LOAD_TIME_WEAVER_BEAN_NAME)) {
beanFactory.addBeanPostProcessor(new LoadTimeWeaverAwareProcessor(beanFactory));
}
...
}对BeanFactory启动处理流程
protected void invokeBeanFactoryPostProcessors(ConfigurableListableBeanFactory beanFactory) {
PostProcessorRegistrationDelegate.invokeBeanFactoryPostProcessors(beanFactory, getBeanFactoryPostProcessors()); //需要注意的有个AspectJWeavingEnabler比较特殊，这个类的目的在于启用ClassLoader级别的Aop，和以前的Instrument In Jvm 有点类似，
// 检测是否有LTW支持，
if (beanFactory.getTempClassLoader() == null && beanFactory.containsBean(LOAD_TIME_WEAVER_BEAN_NAME)) {
beanFactory.addBeanPostProcessor(new LoadTimeWeaverAwareProcessor(beanFactory));
beanFactory.setTempClassLoader(new ContextTypeMatchClassLoader(beanFactory.getBeanClassLoader()));
}
}“java Spring Bean Container的启动加载初始化流程是什么”的内容就介绍到这里了，感谢大家的阅读。如果想了解更多行业相关的知识可以关注创新互联网站，小编将为大家输出更多高质量的实用文章！
