ApplicationContext是对BeanFactory的扩展，实现BeanFactory的所有功能，并添加了事件传播，国际化，资源文件处理等。
configure locations：（CONFIG_LOCATION_DELIMITERS = ",; \t\n" ）分割多个配置文件。
refresh()执行所有逻辑。
@Override
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()：准备需要刷新的资源。
/**
* Prepare this context for refreshing, setting its startup date and
* active flag as well as performing any initialization of property sources.
*/
protected void prepareRefresh() {
this.startupDate = System.currentTimeMillis(); //启动日期
this.closed.set(false); //激活标志
this.active.set(true); //激活标志 if (logger.isInfoEnabled()) {
logger.info("Refreshing " + this);
} // Initialize any placeholder property sources in the context environment
initPropertySources(); //供扩展使用 // Validate that all properties marked as required are resolvable
// see ConfigurablePropertyResolver#setRequiredProperties
getEnvironment().validateRequiredProperties(); // Allow for the collection of early ApplicationEvents,
// to be published once the multicaster is available...
this.earlyApplicationEvents = new LinkedHashSet<ApplicationEvent>();
}
initPropertySources()扩展使用如下：
class MyACTX extends ClassPathXmlApplicationContext {
@Override
protected void initPropertySources() {
super.initPropertySources();
//TODO
}
}
一般不直接实现ApplicationContext(过多接口)，可以继承ClassPathXmlApplicationContext类，然后重写相应的方法。做相关操作。
加载BeanFactory：ConfigurableListableBeanFactory beanFactory = obtainFreshBeanFactory()，（原有功能==配置读取，解析...）。
prepareBeanFactory()：
/**
* Configure the factory's standard context characteristics,
* such as the context's ClassLoader and post-processors.
* @param beanFactory the BeanFactory to configure
*/
protected void prepareBeanFactory(ConfigurableListableBeanFactory beanFactory) {
// Tell the internal bean factory to use the context's class loader etc.
beanFactory.setBeanClassLoader(getClassLoader());
//表达式语言处理器，Spring3 SpEL表达式，#{xx.xx}支持。
beanFactory.setBeanExpressionResolver(new StandardBeanExpressionResolver(beanFactory.getBeanClassLoader()));
//属性编辑器支持 如处理Date注入
beanFactory.addPropertyEditorRegistrar(new ResourceEditorRegistrar(this, getEnvironment())); // Configure the bean factory with context callbacks.
beanFactory.addBeanPostProcessor(new ApplicationContextAwareProcessor(this));
//忽略自动装配的接口
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.
//设置自动装配规则
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.
//AspectJ支持
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());
}
}
SpEL：Spring Expression Language，运行时构造复杂表达式，存取对象图属性，对象方法调用等。SpEL为单独模块，只依赖于core模块。
<bean id="dataSource" class="com.alibaba.druid.pool.DruidDataSource" init-method="init" destroy-method="close">
<property name="driverClassName" value="${dataSource.driverClassName}"/>
<property name="url" value="${dataSource.url}"/>
<property name="username" value="${dataSource.username}"/>
<property name="password" value="${dataSource.password}"/>
<property name="maxActive" value="${dataSource.maxActive}"/>
<property name="minIdle" value="${dataSource.minIdle}" />
<property name="initialSize" value="${dataSource.initialSize}"></property>
<property name="validationQuery" value="${dataSource.validationQuery}"/>
</bean>
PropertyEditor：自定义属性编辑器。
Spring中Date类型无法注入，需要注册相应的属性编辑器来做处理。Spring处理自定义属性编辑器类
org.springframework.beans.factory.config.CustomEditorConfigurer
/**
* {@link BeanFactoryPostProcessor} implementation that allows for convenient
* registration of custom {@link PropertyEditor property editors}.
* 注册
*
*/
public class CustomEditorConfigurer implements BeanFactoryPostProcessor, Ordered { protected final Log logger = LogFactory.getLog(getClass()); private int order = Ordered.LOWEST_PRECEDENCE; // default: same as non-Ordered private PropertyEditorRegistrar[] propertyEditorRegistrars; private Map<Class<?>, Class<? extends PropertyEditor>> customEditors; ... ...
通过注册propertyEditorRegistrars或者customEditors。
customEditors（推荐）：
自定义Date属性编辑器MyDateEditor：
class MyDateEditor extends PropertyEditorSupport {
private String format = "yyyy-MM-dd";
public void setFormat(String format){
this.format = format;
}
@Override
public void setAsText(String text) throws IllegalArgumentException {
SimpleDateFormat sp = new SimpleDateFormat(format);
try{
this.setValue(sp.parse(text));
} catch (ParseException e) {
e.printStackTrace();
}
}
}
配置：
<bean class="org.springframework.beans.factory.config.CustomEditorConfigurer">
<property name="customEditors">
<map>
<entry key="java.util.Date">
<bean class="com.xxx.MyDateEditor">
<property name="format" value="yyyy-MM-dd HH:mm:ss"/>
</bean>
</entry>
</map>
</property>
</bean>
propertyEditorRegistrars：
自定义Date EditorRegister：
class MyDateRegister implements PropertyEditorRegistrar{
private String format = "yyyy-MM-dd";
public void setFormat(String format){
this.format = format;
}
@Override
public void registerCustomEditors(PropertyEditorRegistry registry) {
registry.registerCustomEditor(Date.class, new CustomDateEditor(new SimpleDateFormat(format), true));
}
}
配置：
<bean class="org.springframework.beans.factory.config.CustomEditorConfigurer">
<property name="propertyEditorRegistrars">
<list>
<bean class="com.xxx.MyDateRegister">
<property name="format" value="yyyy-MM-dd HH:mm:ss"/>
</bean>
</list>
</property>
</bean>
属性编辑器应用于Bean实例化属性填充阶段。
invokeBeanFactoryPostProcessors()：容器级别的bean后置处理。
典型应用：PropertyPlaceholderConfigure。
PlaceholderConfigurerSupport extends PropertyResourceConfigurer .. implements BeanFactoryPostProcessor，间接实现BeanFactoryPostProcessor，会在BeanFacty载入bean配置之后进行属性文件的处理 ：mergeProperties、convertProperties、processProperties，供后续bean的实例化使用。
可以注册自定义的BeanFactoryPostProcessor。
initMessageSource()：初始化消息资源，国际化应用。
两个message资源文件message_en.properties, message_zh_CN.properties。
添加Spring配置：messageSource id固定。
<!-- 国际化资源文件 -->
<bean id="messageSource" class="org.springframework.context.support.ResourceBundleMessageSource">
<property name="basenames">
<value>lang/message</value>
</property>
</bean>
读取：
ApplicationContext ctx = new ClassPathXmlApplicationContext("spring/lang-resource.xml");
String msg = ctx.getMessage("xxx", null, Locale.CHINA);
System.out.println(msg);
nitApplicationEventMulticaster()：
/**
* Add beans that implement ApplicationListener as listeners.
* Doesn't affect other listeners, which can be added without being beans.
*/
protected void registerListeners() {
// Register statically specified listeners first.
for (ApplicationListener<?> listener : getApplicationListeners()) {
getApplicationEventMulticaster().addApplicationListener(listener);
} // Do not initialize FactoryBeans here: We need to leave all regular beans
// uninitialized to let post-processors apply to them!
String[] listenerBeanNames = getBeanNamesForType(ApplicationListener.class, true, false);
for (String listenerBeanName : listenerBeanNames) {
getApplicationEventMulticaster().addApplicationListenerBean(listenerBeanName);
} // Publish early application events now that we finally have a multicaster...
Set<ApplicationEvent> earlyEventsToProcess = this.earlyApplicationEvents;
this.earlyApplicationEvents = null;
if (earlyEventsToProcess != null) {
for (ApplicationEvent earlyEvent : earlyEventsToProcess) {
getApplicationEventMulticaster().multicastEvent(earlyEvent);
}
}
}
... ...