Spring源码自学笔记

Spring源码自学笔记

从ClassPathXmlApplicationContext开始

ClassPathXmlApplicationContext的创建流程
ClassPathXmlApplicationContext的继承顺序还是挺复杂的

首先看构造函数中的执行过程

构造函数 setConfigLocations resolvePath getEnvironment resolveRequir setConfigLocations() 根绝配置的xml 文件路径去解析 配置的路径 判断是否有Eve？ 获取环境配置 如何没有环境配置 类，则创建一个S tandardEnvironme nt类 返回StandardEnvironment环境配置 解析每一个配置文件的路径 解析完成 将配一个配置文件路径保存 返回 构造函数 setConfigLocations resolvePath getEnvironment resolveRequir

然后判断是否要刷新
如果刷新，则执行refresh方法去刷新环境变量
refresh方法还比较重要，里面有创建很多东西
代码如下

public ClassPathXmlApplicationContext(String[] configLocations, boolean refresh, ApplicationContext parent)
		throws BeansException {

	super(parent);
	setConfigLocations(configLocations);
	if (refresh) {
		refresh();
	}
}

refresh()方法

ClassPathXmlApplication没有实现refresh方法，使用的父类AbstractRefreshableConfigApplicationContext实现的refresh方法,该方法由ConfigurableApplicationContext 声明

public void refresh() throws BeansException, IllegalStateException {
	synchronized (this.startupShutdownMonitor) {
		// Prepare this context for refreshing.
		// 为刷新做准备
		prepareRefresh();

		// Tell the subclass to refresh the internal bean factory.
		// 让子类去出刷新Bean工厂
		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();
		}
	}
}

环境属性配置

继承

StandardEnvironment

StandardEnvironment

AbstractEnvironment

public static final String ACTIVE_PROFILES_PROPERTY_NAME = "spring.profiles.active";

public static final String IGNORE_GETENV_PROPERTY_NAME = "spring.getenv.ignore";

// 配置使用LinkedHashSet, 保证配置属性的唯一性，并且还可以保证有序性
private final Set activeProfiles = new LinkedHashSet();

// getReservedDefaultProfiles() 方法返回一个　Collections.SingletonSet类型，值就为　default
private final Set defaultProfiles = new LinkedHashSet(getReservedDefaultProfiles());

//PropertySources 的默认实现，用于存储属性PropertySources.
// 保存的主要有　systemProperties　和　systemEnvironment
// 分别存放　jvm的属性　和　系统的属性
private final MutablePropertySources propertySources = new MutablePropertySources(this.logger);

// 创建一个属性解析器，这里使用PropertySourcesPropertyResolver　继承于　AbstractPropertyResolver
private final ConfigurablePropertyResolver propertyResolver =
		new PropertySourcesPropertyResolver(this.propertySources);

AbstractPropertyResolver

使用到　SystemPropertyUtils中的配置

StandardEnvironment

最后创建一个StandardEnvironment类

Assert用法总结

// 判断每个元素的都不能为空
Assert.noNullElements(locations, "Config locations must not be null"); 　

我怎么感觉漏了好多，一定是有哪里错过了
还要慢慢看
跟着源码一次过下来
莫名奇妙的地方太多了
加油!

未完待续,如有错误,欢迎教正,谢谢!