下面要給大家?guī)淼木褪?strong>springioc理解和初始化過程方面的內(nèi)容，你對于這點有足夠的了解嗎?一起通過下文來進行學(xué)習(xí)吧。
下面對spring ioc容器的啟動過程進行一下詳細的介紹：
啟動容器
AnnotationConfigApplicationContext anno = new AnnotationConfigApplicationContext(MainConfig.class);
進入AnnotationConfigApplicationContext類當(dāng)中。
代碼，scan方法對包進行掃描，進行refresh方法，容器的刷新和IOC容器的創(chuàng)建。
public AnnotationConfigApplicationContext(String...basePackages)
{
this();
this.scan(basePackages);
this.refresh();
}首先的話是refresh方法加入線程安全鎖，之后再調(diào)用prepareRefresh方法中，進行類加載前的刷新前的預(yù)處理。
public void refresh() throws BeansException, IllegalStateException
{
synchronized(this.startupShutdownMonitor)
{ //加入線程安全鎖
this.prepareRefresh();
ConfigurableListableBeanFactory beanFactory = this.obtainFreshBeanFactory();
this.prepareBeanFactory(beanFactory);
try
{
this.postProcessBeanFactory(beanFactory);
this.invokeBeanFactoryPostProcessors(beanFactory);
this.registerBeanPostProcessors(beanFactory);
this.initMessageSource();
this.initApplicationEventMulticaster();
this.onRefresh();
this.registerListeners();
this.finishBeanFactoryInitialization(beanFactory);
this.finishRefresh();
}
catch (BeansException var9)
{
if (this.logger.isWarnEnabled())
{
this.logger.warn("Exception encountered during context initialization - cancelling refresh attempt: " + var9);
}
this.destroyBeans();
this.cancelRefresh(var9);
throw var9;
}
finally
{
this.resetCommonCaches();
}
}
}進入prepareRefresh方法中。
這個方法是由AbstractApplicationContext抽象類提供的公共方法。
protected void prepareRefresh()
{
this.startupDate = System.currentTimeMillis(); //記錄開始時間
this.closed.set(false); //記錄狀態(tài)，當(dāng)前容器關(guān)不了嗎？
this.active.set(true);
if (this.logger.isInfoEnabled())
{
this.logger.info("Refreshing " + this);
}
this.initPropertySources(); //初始化一些屬性設(shè)計（此方法為空，留在子類做事情的，由子類來自定義屬性設(shè)置）
this.getEnvironment()
.validateRequiredProperties(); //檢驗屬性的合法性
this.earlyApplicationEvents = new linkedHashSet(); //保存容器中早期的一些事件
}通過obtainFreshBeanFactory方法獲取BeanFactory。
這個方法一個是refreshBeanFactory方法另一個是getBeanFactory方法。
protected ConfigurableListableBeanFactory obtainFreshBeanFactory()
{
this.refreshBeanFactory(); //刷新BeanFactory
ConfigurableListableBeanFactory beanFactory = this.getBeanFactory(); //獲取BeanFactory的對象
if (this.logger.isDebugEnabled())
{
this.logger.debug("Bean factory for " + this.getDisplayName() + ": " + beanFactory);
}
return beanFactory;
}進入refreshBeanFactory方式當(dāng)中。
這個方法是AbstractApplicationContext類提供一個抽象的方法，GenericApplicationContext類實現(xiàn)了這個方法，設(shè)置了id標(biāo)識并創(chuàng)建beanFactory對象。
protected final void refreshBeanFactory() throws IllegalStateException
{
if (!this.refreshed.compareAndSet(false, true))
{
throw new IllegalStateException("GenericApplicationContext does not support multiple refresh attempts: just call refresh once");
}
else
{
this.beanFactory.setSerializationId(this.getId());
}
}現(xiàn)在執(zhí)行this.prepareBeanFactory(beanFactory)方法，這個方法BeanFactory的預(yù)準(zhǔn)備工作(對beanFactory進行設(shè)置)。
protected void prepareBeanFactory(ConfigurableListableBeanFactory beanFactory)
{
beanFactory.setBeanClassLoader(this.getClassLoader()); //設(shè)置BeanFactory的類加載器
beanFactory.setBeanexpressionResolver(new StandardBeanexpressionResolver(beanFactory.getBeanClassLoader())); //支持表達式解析器
beanFactory.addPropertyEditorRegistrar(new ResourceEditorRegistrar(this, this.getEnvironment()));
beanFactory.addBeanPostProcessor(new ApplicationContextAwareProcessor(this)); //設(shè)置PostProcessorf
//設(shè)置忽略的自動裝配的接口
beanFactory.ignoreDependencyInterface(EnvironmentAware.class);
beanFactory.ignoreDependencyInterface(EmbeddedValueResolverAware.class);
beanFactory.ignoreDependencyInterface(ResourceLoaderAware.class);
beanFactory.ignoreDependencyInterface(ApplicationEventPublisherAware.class);
beanFactory.ignoreDependencyInterface(MessageSourceAware.class);
beanFactory.ignoreDependencyInterface(ApplicationContextAware.class);
//注冊可以解析自動裝配；我們能直接在任何組件中自動注入
//BeanFactory、ResourceLoader、ApplicationEventPublisher、ApplicationContext
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)); //添加編譯時的AspectJ
if (beanFactory.containsBean("loadTimeWeaver"))
{
beanFactory.addBeanPostProcessor(new LoadTimeWeaverAwareProcessor(beanFactory));
beanFactory.setTempClassLoader(new ContextTypeMatchClassLoader(beanFactory.getBeanClassLoader()));
}
if (!beanFactory.containsLocalBean("environment"))
{ //環(huán)境
beanFactory.registerSingleton("environment", this.getEnvironment());
}
if (!beanFactory.containsLocalBean("systemProperties"))
{ //系統(tǒng)屬性
beanFactory.registerSingleton("systemProperties", this.getEnvironment()
.getSystemProperties());
}
if (!beanFactory.containsLocalBean("systemEnvironment"))
{ //系統(tǒng)環(huán)境信息
beanFactory.registerSingleton("systemEnvironment", this.getEnvironment()
.getSystemEnvironment());
}
}this.postProcessBeanFactory(beanFactory)方法對BeanFactory準(zhǔn)備工作完成之后，進行的后置處理工作。
方法為空。
子類通過重寫這個方法在BeanFactory創(chuàng)建并且準(zhǔn)備完成以后做進一步的設(shè)置。
上面的內(nèi)容是BeanFactory的創(chuàng)建和預(yù)準(zhǔn)備工作。
this.invokeBeanFactoryPostProcessors(beanFactory)方法進行BeanFactory的后置處理器。在BeanFactory標(biāo)準(zhǔn)初始化之后執(zhí)行的。
protected void invokeBeanFactoryPostProcessors(ConfigurableListableBeanFactory beanFactory)
{
PostProcessorRegistrationDelegate.invokeBeanFactoryPostProcessors(beanFactory, this.getBeanFactoryPostProcessors());
if (beanFactory.getTempClassLoader() == null && beanFactory.containsBean("loadTimeWeaver"))
{
beanFactory.addBeanPostProcessor(new LoadTimeWeaverAwareProcessor(beanFactory));
beanFactory.setTempClassLoader(new ContextTypeMatchClassLoader(beanFactory.getBeanClassLoader()));
}
}執(zhí)行BeanFactoryProcessorr的方法。
跟進這個方法。
public static void invokeBeanFactoryPostProcessors(ConfigurableListableBeanFactory beanFactory, List < BeanFactoryPostProcessor > beanFactoryPostProcessors)
{
Set < String > processedBeans = new HashSet();
int var9;
ArrayList currentRegistryProcessors;
String[] postProcessorNames;
if (beanFactory instanceof BeanDefinitionRegistry)
{ //先判斷BeanFactory是不是BeanDefinitionRegistry類型
BeanDefinitionRegistry registry = (BeanDefinitionRegistry) beanFactory;
List < BeanFactoryPostProcessor > regularPostProcessors = new linkedList();
List < BeanDefinitionRegistryPostProcessor > registryProcessors = new linkedList();
Iterator var6 = beanFactoryPostProcessors.iterator();
while (var6.hasNext())
{
BeanFactoryPostProcessor postProcessor = (BeanFactoryPostProcessor) var6.next();
if (postProcessor instanceof BeanDefinitionRegistryPostProcessor)
{
BeanDefinitionRegistryPostProcessor registryProcessor = (BeanDefinitionRegistryPostProcessor) postProcessor;
registryProcessor.postProcessBeanDefinitionRegistry(registry);
registryProcessors.add(registryProcessor);
}
else
{
regularPostProcessors.add(postProcessor);
}
}
currentRegistryProcessors = new ArrayList();
postProcessorNames = beanFactory.getBeanNamesForType(BeanDefinitionRegistryPostProcessor.class, true, false); //獲取BeanDefinitionRegistryPostProcessor
String[] var18 = postProcessorNames;
var9 = postProcessorNames.length;
int var10;
String ppName;
//遍歷所有的BeanDifinitionRgPostProcessor
for (var10 = 0; var10 < var9; ++var10)
{
ppName = var18[var10];
if (beanFactory.isTypeMatch(ppName, PriorityOrdered.class))
{ //判斷是否實現(xiàn)了PriortyOrder接口
currentRegistryProcessors.add(beanFactory.getBean(ppName, BeanDefinitionRegistryPostProcessor.class));
processedBeans.add(ppName); //將處理過的bean存儲起來
}
}
sortPostProcessors(currentRegistryProcessors, beanFactory); //優(yōu)先級進行排序
registryProcessors.addAll(currentRegistryProcessors);
invokeBeanDefinitionRegistryPostProcessors(currentRegistryProcessors, registry); //進行執(zhí)行
currentRegistryProcessors.clear(); //清楚
//在執(zhí)行實現(xiàn)了Ordered順序接口的BeanDefinitionRegistryPostProcessor
postProcessorNames = beanFactory.getBeanNamesForType(BeanDefinitionRegistryPostProcessor.class, true, false);
var18 = postProcessorNames;
var9 = postProcessorNames.length;
for (var10 = 0; var10 < var9; ++var10)
{
ppName = var18[var10];
if (!processedBeans.contains(ppName) && beanFactory.isTypeMatch(ppName, Ordered.class))
{
currentRegistryProcessors.add(beanFactory.getBean(ppName, BeanDefinitionRegistryPostProcessor.class));
processedBeans.add(ppName);
}
}
sortPostProcessors(currentRegistryProcessors, beanFactory);
registryProcessors.addAll(currentRegistryProcessors);
invokeBeanDefinitionRegistryPostProcessors(currentRegistryProcessors, registry);
currentRegistryProcessors.clear();
boolean reiterate = true;
while (reiterate)
{
reiterate = false;
postProcessorNames = beanFactory.getBeanNamesForType(BeanDefinitionRegistryPostProcessor.class, true, false);
String[] var21 = postProcessorNames;
var10 = postProcessorNames.length;
for (int var28 = 0; var28 < var10; ++var28)
{
String ppName = var21[var28];
if (!processedBeans.contains(ppName))
{
currentRegistryProcessors.add(beanFactory.getBean(ppName, BeanDefinitionRegistryPostProcessor.class));
processedBeans.add(ppName);
reiterate = true;
}
}
sortPostProcessors(currentRegistryProcessors, beanFactory);
registryProcessors.addAll(currentRegistryProcessors);
invokeBeanDefinitionRegistryPostProcessors(currentRegistryProcessors, registry);
currentRegistryProcessors.clear();
}
invokeBeanFactoryPostProcessors((Collection) registryProcessors, (ConfigurableListableBeanFactory) beanFactory);
invokeBeanFactoryPostProcessors((Collection) regularPostProcessors, (ConfigurableListableBeanFactory) beanFactory);
}
else
{
invokeBeanFactoryPostProcessors((Collection) beanFactoryPostProcessors, (ConfigurableListableBeanFactory) beanFactory);
}
String[] postProcessorNames = beanFactory.getBeanNamesForType(BeanFactoryPostProcessor.class, true, false);
List < BeanFactoryPostProcessor > priorityOrderedPostProcessors = new ArrayList();
List < String > orderedPostProcessorNames = new ArrayList();
currentRegistryProcessors = new ArrayList();
postProcessorNames = postProcessorNames;
int var22 = postProcessorNames.length;
String ppName;
for (var9 = 0; var9 < var22; ++var9)
{
ppName = postProcessorNames[var9];
if (!processedBeans.contains(ppName))
{
if (beanFactory.isTypeMatch(ppName, PriorityOrdered.class))
{
priorityOrderedPostProcessors.add(beanFactory.getBean(ppName, BeanFactoryPostProcessor.class));
}
else if (beanFactory.isTypeMatch(ppName, Ordered.class))
{
orderedPostProcessorNames.add(ppName);
}
else
{
currentRegistryProcessors.add(ppName);
}
}
}
sortPostProcessors(priorityOrderedPostProcessors, beanFactory);
invokeBeanFactoryPostProcessors((Collection) priorityOrderedPostProcessors, (ConfigurableListableBeanFactory) beanFactory);
List < BeanFactoryPostProcessor > orderedPostProcessors = new ArrayList();
Iterator var23 = orderedPostProcessorNames.iterator();
while (var23.hasNext())
{
String postProcessorName = (String) var23.next();
orderedPostProcessors.add(beanFactory.getBean(postProcessorName, BeanFactoryPostProcessor.class));
}
sortPostProcessors(orderedPostProcessors, beanFactory);
invokeBeanFactoryPostProcessors((Collection) orderedPostProcessors, (ConfigurableListableBeanFactory) beanFactory);
List < BeanFactoryPostProcessor > nonOrderedPostProcessors = new ArrayList();
Iterator var26 = currentRegistryProcessors.iterator();
while (var26.hasNext())
{
ppName = (String) var26.next();
nonOrderedPostProcessors.add(beanFactory.getBean(ppName, BeanFactoryPostProcessor.class));
}
invokeBeanFactoryPostProcessors((Collection) nonOrderedPostProcessors, (ConfigurableListableBeanFactory) beanFactory);
beanFactory.clearmetadataCache();
}invokeBeanDefinitionRegistryPostProcessors方法中，在執(zhí)行實現(xiàn)了Ordered順序接口的BeanDefinitionRegistryPostProcessor;
private static void invokeBeanDefinitionRegistryPostProcessors(Collection < ? extends BeanDefinitionRegistryPostProcessor > postProcessors, BeanDefinitionRegistry registry)
{
Iterator var2 = postProcessors.iterator();
while (var2.hasNext())
{
BeanDefinitionRegistryPostProcessor postProcessor = (BeanDefinitionRegistryPostProcessor) var2.next();
postProcessor.postProcessBeanDefinitionRegistry(registry);
}
}this.registerBeanPostProcessors(beanFactory)這個方法為注冊BeanPostProcessor(Bean的后置處理器)。
{
//獲取所有的后置處理器
String[] postProcessorNames = beanFactory.getBeanNamesForType(BeanPostProcessor.class, true, false);
int beanProcessorTargetCount = beanFactory.getBeanPostProcessorCount() + 1 + postProcessorNames.length;
beanFactory.addBeanPostProcessor(new PostProcessorRegistrationDelegate.BeanPostProcessorChecker(beanFactory, beanProcessorTargetCount));
List < BeanPostProcessor > priorityOrderedPostProcessors = new ArrayList();
List < BeanPostProcessor > internalPostProcessors = new ArrayList();
List < String > orderedPostProcessorNames = new ArrayList();
List < String > nonOrderedPostProcessorNames = new ArrayList();
String[] var8 = postProcessorNames;
int var9 = postProcessorNames.length;
String ppName;
BeanPostProcessor pp;
//循環(huán)所有的后置處理器，進行優(yōu)先級的處理
for (int var10 = 0; var10 < var9; ++var10)
{
ppName = var8[var10];
if (beanFactory.isTypeMatch(ppName, PriorityOrdered.class))
{ //判斷是否是PriorityOrdered類型的類添加到priorityOrderedPostProcessors集合中
pp = (BeanPostProcessor) beanFactory.getBean(ppName, BeanPostProcessor.class);
priorityOrderedPostProcessors.add(pp);
if (pp instanceof MergedBeanDefinitionPostProcessor)
{
internalPostProcessors.add(pp);
}
}
else if (beanFactory.isTypeMatch(ppName, Ordered.class))
{ //判斷是否是Ordered類型添加到orderedPostProcessorNames集合中
orderedPostProcessorNames.add(ppName);
}
else
{
nonOrderedPostProcessorNames.add(ppName);
}
}
//對priorityOrderedPostProcessors進行排序
sortPostProcessors(priorityOrderedPostProcessors, beanFactory);、
registerBeanPostProcessors(beanFactory, (List) priorityOrderedPostProcessors);
List < BeanPostProcessor > orderedPostProcessors = new ArrayList();
Iterator var14 = orderedPostProcessorNames.iterator();
while (var14.hasNext())
{
String ppName = (String) var14.next();
BeanPostProcessor pp = (BeanPostProcessor) beanFactory.getBean(ppName, BeanPostProcessor.class);
orderedPostProcessors.add(pp); //添加到orderedPostProcessors中
//MergedBeanDefinitionPostProcessor則是在合并處理Bean定義的時候的回調(diào)。也基本是框架內(nèi)部使用的，
if (pp instanceof MergedBeanDefinitionPostProcessor)
{
internalPostProcessors.add(pp);
}
}
//對orderedPostProcessors進行排序
sortPostProcessors(orderedPostProcessors, beanFactory);
registerBeanPostProcessors(beanFactory, (List) orderedPostProcessors);
List < BeanPostProcessor > nonOrderedPostProcessors = new ArrayList();
Iterator var17 = nonOrderedPostProcessorNames.iterator();
while (var17.hasNext())
{
ppName = (String) var17.next();
pp = (BeanPostProcessor) beanFactory.getBean(ppName, BeanPostProcessor.class);
nonOrderedPostProcessors.add(pp);
//MergedBeanDefinitionPostProcessor則是在合并處理Bean定義的時候的回調(diào)。也基本是框架內(nèi)部使用的，
if (pp instanceof MergedBeanDefinitionPostProcessor)
{
internalPostProcessors.add(pp);
}
}
registerBeanPostProcessors(beanFactory, (List) nonOrderedPostProcessors);
sortPostProcessors(internalPostProcessors, beanFactory);
registerBeanPostProcessors(beanFactory, (List) internalPostProcessors);
//注冊一個ApplicationListenerDetector；來在Bean創(chuàng)建完成后檢查是否是ApplicationListener
beanFactory.addBeanPostProcessor(new ApplicationListenerDetector(applicationContext));
}this.initMessageSource()方法為初始化MessageSource組件(做國際化，消息綁定，消息解析)。
protected void initMessageSource()
{
//獲取Beanfactory
ConfigurableListableBeanFactory beanFactory = this.getBeanFactory();
//判斷beanFactory中是否存在messageSource類
if (beanFactory.containsLocalBean("messageSource"))
{
//獲取messageSource類
this.messageSource = (MessageSource) beanFactory.getBean("messageSource", MessageSource.class);
if (this.parent != null && this.messageSource instanceof HierarchicalMessageSource)
{
HierarchicalMessageSource hms = (HierarchicalMessageSource) this.messageSource;
if (hms.getParentMessageSource() == null)
{
hms.setParentMessageSource(this.getInternalParentMessageSource());
}
}
if (this.logger.isDebugEnabled())
{
this.logger.debug("Using MessageSource [" + this.messageSource + "]");
}
}
else
{
//如果不存在，new一個DelegatingMessageSource
DelegatingMessageSource dms = new DelegatingMessageSource();
dms.setParentMessageSource(this.getInternalParentMessageSource());
this.messageSource = dms;
beanFactory.registerSingleton("messageSource", this.messageSource);
if (this.logger.isDebugEnabled())
{
this.logger.debug("Unable to locate MessageSource with name messageSource: using default [" + this.messageSource + "]");
}
}
}this.initApplicationEventMulticaster方法為初始化事件派發(fā)器。
protected void initApplicationEventMulticaster()
{
ConfigurableListableBeanFactory beanFactory = this.getBeanFactory();
//判斷工廠是否存在applicationEventMulticaster的applicationEventMulticaster
if (beanFactory.containsLocalBean("applicationEventMulticaster"))
{
this.applicationEventMulticaster = (ApplicationEventMulticaster) beanFactory.getBean("applicationEventMulticaster", ApplicationEventMulticaster.class);
if (this.logger.isDebugEnabled())
{
this.logger.debug("Using ApplicationEventMulticaster [" + this.applicationEventMulticaster + "]");
}
}
else
{
//如果不存在,自己創(chuàng)建一個DelegatingMessageSource
this.applicationEventMulticaster = new SimpleApplicationEventMulticaster(beanFactory);
beanFactory.registerSingleton("applicationEventMulticaster", this.applicationEventMulticaster);
if (this.logger.isDebugEnabled())
{
this.logger.debug("Unable to locate ApplicationEventMulticaster with name applicationEventMulticaster: using default [" + this.applicationEventMulticaster + "]");
}
}
}onrefresh();//空方法,留給子容器(子類),子類重寫這個方法，在容器刷新的時候可以自定義邏輯。
protected void onRefresh() throws BeansException
{}this.registerListeners()方法將容器中所有項目里面的ApplicationListener注冊進來。
protected void registerListeners()
{
Iterator var1 = this.getApplicationListeners()
.iterator(); //獲取時間派發(fā)器中的監(jiān)聽
while (var1.hasNext())
{
ApplicationListener < ? > listener = (ApplicationListener) var1.next();
//將監(jiān)聽添加到事件派發(fā)器中
this.getApplicationEventMulticaster()
.addApplicationListener(listener); //添加監(jiān)聽
}
//從容器中獲取監(jiān)聽
String[] listenerBeanNames = this.getBeanNamesForType(ApplicationListener.class, true, false);
String[] var7 = listenerBeanNames;
int var3 = listenerBeanNames.length;
for (int var4 = 0; var4 < var3; ++var4)
{
String listenerBeanName = var7[var4];
//將監(jiān)聽添加到事件派發(fā)器中 this.getApplicationEventMulticaster().addApplicationListenerBean(listenerBeanName);
}
Set < ApplicationEvent > earlyEventsToProcess = this.earlyApplicationEvents;
this.earlyApplicationEvents = null;
if (earlyEventsToProcess != null)
{
Iterator var9 = earlyEventsToProcess.iterator();
while (var9.hasNext())
{
ApplicationEvent earlyEvent = (ApplicationEvent) var9.next();
//派發(fā)之前步驟產(chǎn)生的事件
this.getApplicationEventMulticaster()
.multicastEvent(earlyEvent);
}
}
}this.finishBeanFactoryInitialization(beanFactory)方法將所有單實例bean創(chuàng)建。
finishRefresh()完成BeanFactory的初始化創(chuàng)建工作，ioc容器創(chuàng)建完成。
protected void finishRefresh()
{
//清除環(huán)境級別的緩存
this.clearResourceCaches();
//初始化與生命周期有關(guān)的后置處理
this.initLifecycleProcessor();
//拿到上面定義的生命周期處理器，回調(diào)onRefresh
this.getLifecycleProcessor()
.onRefresh();
//發(fā)布容器刷新完成容器時間
this.publishEvent((ApplicationEvent)(new ContextRefreshedEvent(this)));
//暴露一些 Mbean類
LiveBeansView.registerApplicationContext(this);
}
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