Spring源码解析-beanfactory.doc

Spring源码解析-beanfactoryDemopublic class MyBeanTest public static void main(String args) BeanFactory ctx = new XmlBeanFactory(new ClassPathResource(spring.xml); MyBean testBean = (MyBean)ctx.getBean(testBean); System.out.println(testBean.getTestStr(); package qbb.spring.bean;public class MyBean private String testStr = testStr; public MyBean() public MyBean(String testStr) this.testStr = testStr; public String getTestStr() return testStr; public void setTestStr(String testStr) this.testStr = testStr; beans xmlns=/schema/beans xmlns:xsi=/2001/XMLSchema-instance xmlns:context=/schema/context xsi:schemaLocation=/schema/beans uml类图上次看的时候就画过这个图，这次做了细化和调整。XmlBeanFactory继承关系AliasRegistry定义对Alias的简单增删改等操作;SimpleAliasRegistry使用currenthashmap作为缓存，并对接口AliasRegisty进行实现;SingletonBeanRegistry定义对单例的获取及获取;DefaultSingletonBeanRegistry是SingletonBeanRegistry的实现;FactoryBeanRegistrySupport在DefaultSingletonBeanRegistry基础上，增加对FactorBean的特殊处理功能;BeanFactory定义获取bean及bean的各种属性;HierarchicalBeanFactory继承BeanFactory，增加对parentFactory的支持;ConfigurableBeanFactory提供配置各种factory的方法;ListableBeanFactory根据不同条件获取bean的配置清单;AutowireCapableBeanFactory提供创建bean，自动注入，初始化已经应用bean后的处理器;AbstractBeanFactory综合FactoryBeanRegistrySupport和ConfigurableBeanFactory功能;ConfigurableListableBeanFactory是BeanFactory的配置清单,指定忽略类型和接口等;AbstractAutowireCapableBeanFactory综合AbstractBeanFactory并对接口AutowireCapalbeBeanFactory的实现;BeanDefinitionRegistry定义对BeanDefinition的curd操作;DefaultListableBeanFactory综合所有功能，主要是bean注册后的处理;XmlBeanFactory对DefaultListableBeanFactory类进行了扩展，主要是从xml文档读取BeanDefinition,对于注册以及获取Bean都是从父类DefaultLisstableBean继承的方法去实现，与父类的不同就是增加了XmlBeanDefinitionReader类型的reader属性,在XmlBeanFactory中主要使用reader属性对资源文件进行读取和注册;XmlBeanDefinitionReaderEnvironmentCapable定义获取Environment的方法;BeanDefinitionReader主要定义资源文件读取并转化为BeanDefinition的各种功能;AbstractBeanDefinitionReader对接口的实现;ResourceLoader资源加载器，根据给定的资源文件地址返回对应的Resource;DocumentLoader资源文件转化为Document的功能;BeanDefinitionDocumentReader读取Document并注册BeanFinition的功能;BeanDefinitionParserDelegate定义解析element的各种方法;BeanDefinitionBeanDefinition配置文件bean元素在容器的内部表现形式;ChildBeanDefinition父子bean中的子bean;GenericBeanDefinition2.5后加入，一站式的服务类;RootBeanDefinition对应一般性的bean元素标签，父子bean中的父bean可以用此表示,没有父bean的bean也使用来表示;xml解析beanDefinitionBeanFactory ctx = new XmlBeanFactory(new ClassPathResource(spring.xml);资源文件抽象new ClassPathResource(spring.xml)spring将外部的资源封装成内部使用Resource，可以从文件，class，jar，还有context上下文：我这里使用ClassPathResource加载spring文件，当然也可以使用FileSystemResource从文件系统路径加载。loadBeanDefinitionnew XmlBeanFactory(new ClassPathResource(spring.xml);调用XmlBeanFactory构造/ XmlBeanFactorypublic XmlBeanFactory(Resource resource) throws BeansException this(resource, null);public XmlBeanFactory(Resource resource, BeanFactory parentBeanFactory) throws BeansException super(parentBeanFactory); this.reader.loadBeanDefinitions(resource);在条用super的时候会设置parentBeanFactory，好像只要mvc的时候才看到设置，其他地方基本没用到。/AbstractAutowireCapableBeanFactorypublic AbstractAutowireCapableBeanFactory(BeanFactory parentBeanFactory) this(); setParentBeanFactory(parentBeanFactory);public AbstractAutowireCapableBeanFactory() super(); /忽略一些依赖，在getbean的时候，在实例化属性填充后，会检查设置这些依赖关系， /然后再去调用实现InitializingBean的afterPropertiesSet方法和自定义的Init-Method ignoreDependencyInterface(BeanNameAware.class); ignoreDependencyInterface(BeanFactoryAware.class); ignoreDependencyInterface(BeanClassLoaderAware.class);/AbstractBeanFactorypublic void setParentBeanFactory(BeanFactory parentBeanFactory) if (this.parentBeanFactory != null & this.parentBeanFactory != parentBeanFactory) throw new IllegalStateException(Already associated with parent BeanFactory: + this.parentBeanFactory); this.parentBeanFactory = parentBeanFactory;在这些完了后会调用/xmlbeanfactorythis.reader.loadBeanDefinitions(resource);XmlBeanFactory使用XmlBeanDefinitionReader来解析和注册bean定义。/XmlBeanDefinitionReaderpublic int loadBeanDefinitions(Resource resource) throws BeanDefinitionStoreException /EncodedResource做了编码处理，getReader时如果有编码就使用，没有就不适用 return loadBeanDefinitions(new EncodedResource(resource);public int loadBeanDefinitions(EncodedResource encodedResource) throws BeanDefinitionStoreException . try InputStream inputStream = encodedResource.getResource().getInputStream(); try InputSource inputSource = new InputSource(inputStream); if (encodedResource.getEncoding() != null) inputSource.setEncoding(encodedResource.getEncoding(); return doLoadBeanDefinitions(inputSource, encodedResource.getResource(); finally inputStream.close(); .看了下，spring中习惯doXXX来表示真正干活的代码，XXX来做主流程控制。自己写代码的时候有时流程会不清晰，会乱，后来还是从spring里面学会这招，先提炼主流程，然后再分配。/XmlBeanDefinitionReaderprotected int doLoadBeanDefinitions(InputSource inputSource, Resource resource) throws BeanDefinitionStoreException try int validationMode = getValidationModeForResource(resource); Document doc = this.documentLoader.loadDocument( inputSource, getEntityResolver(), this.errorHandler, validationMode, isNamespaceAware(); return registerBeanDefinitions(doc, resource); .xml文件校验和解析/XmlBeanDefinitionReaderint validationMode = getValidationModeForResource(resource); Document doc = this.documentLoader.loadDocument( inputSource, getEntityResolver(), this.errorHandler, validationMode, isNamespaceAware();xml文档的2种校验方式：DTD和XSD，通过getValidationModeForResource来获取，DTD的会包含DOCTYPE，所以通过解析这个是否存在判断。校验过后就是通过DefaultDocumentLoader将xml文件解析Document，xml文件解析一般就是SAX、Dom、jdom，dom4j。registerBeanDefinitions/XmlBeanDefinitionReaderpublic int registerBeanDefinitions(Document doc, Resource resource) throws BeanDefinitionStoreException /将DefaultBeanDefinitionDocumentReader转为BeanDefinitionDocumentReader BeanDefinitionDocumentReader documentReader = createBeanDefinitionDocumentReader(); /this.getEnvironment()获取到的是StandardEnvironment，可以用来获取系统变量和环境变量 documentReader.setEnvironment(this.getEnvironment(); int countBefore = getRegistry().getBeanDefinitionCount(); /使用DefaultBeanDefinitionDocumentReader解析document documentReader.registerBeanDefinitions(doc, createReaderContext(resource); return getRegistry().getBeanDefinitionCount() - countBefore;protected XmlReaderContext createReaderContext(Resource resource) if (spaceHandlerResolver = null) /DefaultNamespaceHandlerResolver，主要用来获取标签的解析， /特别是自定义标签的解析，后面单独讲下这个,里面最重要的方法NamespaceHandler resolve(String namespaceUri) spaceHandlerResolver = createDefaultNamespaceHandlerResolver(); return new XmlReaderContext(resource, blemReporter, this.eventListener, this.sourceExtractor, this, spaceHandlerResolver);最终还是委托DefaultBeanDefinitionDocumentReader来解析Document。/DefaultBeanDefinitionDocumentReaderpublic void registerBeanDefinitions(Document doc, XmlReaderContext readerContext) this.readerContext = readerContext; logger.debug(Loading bean definitions); Element root = doc.getDocumentElement(); doRegisterBeanDefinitions(root);protected void doRegisterBeanDefinitions(Element root) /profile属性，类似maven -p，可以定义不同环境下的bean定义，配合环境变量files.active使用 String profileSpec = root.getAttribute(PROFILE_ATTRIBUTE); if (StringUtils.hasText(profileSpec) Assert.state(this.environment != null, environment property must not be null); String specifiedProfiles = StringUtils.tokenizeToStringArray(profileSpec, BeanDefinitionParserDelegate.MULTI_VALUE_ATTRIBUTE_DELIMITERS); if (!this.environment.acceptsProfiles(specifiedProfiles) return; / any nested elements will cause recursion in this method. In / order to propagate and preserve default-* attributes correctly, / keep track of the current (parent) delegate, which may be null. Create / the new (child) delegate with a reference to the parent for fallback purposes, / then ultimately reset this.delegate back to its original (parent) reference. / this behavior emulates a stack of delegates without actually necessitating one. BeanDefinitionParserDelegate parent = this.delegate; / BeanDefinitionParserDelegate this.delegate = createHelper(readerContext, root, parent); preProcessXml(root); /子类实现 parseBeanDefinitions(root, this.delegate); postProcessXml(root); /子类实现 this.delegate = parent;protected BeanDefinitionParserDelegate createHelper(XmlReaderContext readerContext, Element root, BeanDefinitionParserDelegate parentDelegate) BeanDefinitionParserDelegate delegate = new BeanDefinitionParserDelegate(readerContext, environment); delegate.initDefaults(root, parentDelegate); return delegate;/BeanDefinitionParserDelegatepublic void initDefaults(Element root, BeanDefinitionParserDelegate parent) populateDefaults(this.defaults, (parent != null ? parent.defaults : null), root); this.readerContext.fireDefaultsRegistered(this.defaults);/收集一些默认属性protected void populateDefaults(DocumentDefaultsDefinition defaults, DocumentDefaultsDefinition parentDefaults, Element root) String lazyInit = root.getAttribute(DEFAULT_LAZY_INIT_ATTRIBUTE); if (DEFAULT_VALUE.equals(lazyInit) lazyInit = parentDefaults != null ? parentDefaults.getLazyInit() : FALSE_VALUE; defaults.setLazyInit(lazyInit); String merge = root.getAttribute(DEFAULT_MERGE_ATTRIBUTE); if (DEFAULT_VALUE.equals(merge) merge = parentDefaults != null ? parentDefaults.getMerge() : FALSE_VALUE; defaults.setMerge(merge); String autowire = root.getAttribute(DEFAULT_AUTOWIRE_ATTRIBUTE); if (DEFAULT_VALUE.equals(autowire) autowire = parentDefaults != null ? parentDefaults.getAutowire() : AUTOWIRE_NO_VALUE; defaults.setAutowire(autowire); / dont fall back to parentDefaults for dependency-check as its no / longer supported in as of 3.0. Therefore, no nested / would ever need to fall back to it. defaults.setDependencyCheck(root.getAttribute(DEFAULT_DEPENDENCY_CHECK_ATTRIBUTE); if (root.hasAttribute(DEFAULT_AUTOWIRE_CANDIDATES_ATTRIBUTE) defaults.setAutowireCandidates(root.getAttribute(DEFAULT_AUTOWIRE_CANDIDATES_ATTRIBUTE); else if (parentDefaults != null) defaults.setAutowireCandidates(parentDefaults.getAutowireCandidates(); if (root.hasAttribute(DEFAULT_INIT_METHOD_ATTRIBUTE) defaults.setInitMethod(root.getAttribute(DEFAULT_INIT_METHOD_ATTRIBUTE); else if (parentDefaults != null) defaults.setInitMethod(parentDefaults.getInitMethod(); if (root.hasAttribute(DEFAULT_DESTROY_METHOD_ATTRIBUTE) defaults.setDestroyMethod(root.getAttribute(DEFAULT_DESTROY_METHOD_ATTRIBUTE); else if (parentDefaults != null) defaults.setDestroyMethod(parentDefaults.getDestroyMethod(); defaults.setSource(this.readerContext.extractSource(root);parseBeanDefinitions/DefaultBeanDefinitionDocumentReaderprotected void parseBeanDefinitions(Element root, BeanDefinitionParserDelegate delegate) /默认是bean if (delegate.isDefaultNamespace(root) NodeList nl = root.getChildNodes(); for (int i = 0; i nl.getLength(); i+) Node node = nl.item(i); if (node instanceof Element) Element ele = (Element) node; if (delegate.isDefaultNamespace(ele) /解析默认bean定义 parseDefaultElement(ele, delegate); else /自定义 delegate.parseCustomElement(ele); else /自定义 delegate.parseCustomElement(root); private void parseDefaultElement(Element ele, BeanDefinitionParserDelegate delegate) /import if (delegate.nodeNameEquals(ele, IMPORT_ELEMENT) importBeanDefinitionResource(ele); /别名 else if (delegate.nodeNameEquals(ele, ALIAS_ELEMENT) processAliasRegistration(ele); /bean else if (delegate.nodeNameEquals(ele, BEAN_ELEMENT) processBeanDefinition(ele, delegate); /beans里面嵌套的bean解析 else if (delegate.nodeNameEquals(ele, NESTED_BEANS_ELEMENT) / recurse doRegisterBeanDefinitions(ele); /BeanDefinitionParserDelegatepublic boolean isDefaultNamespace(String namespaceUri) /BEANS_NAMESPACE_URI = /schema/beans; return (!StringUtils.hasLength(namespaceUri) | BEANS_NAMESPACE_URI.equals(namespaceUri);public boolean isDefaultNamespace(Node node) return isDefaultNamespace(getNamespaceURI(node);可以看到这里的Document解析节点是先校验是否为默认bean的namespace，是的话就判断节点是import、alias、bean，不是就按照自定义namespace方式解析。对于import的解析时循环解析import的Resource文件，alias是注册别名到map（会校验是否存在别名的循环定义），最核心的还是bean的解析。processBeanDefinition/DefaultBeanDefinitionDocumentReaderprotected void processBeanDefinition(Element ele, BeanDefinitionParserDelegate delegate) /委托DefaultBeanDefinitionDocumentReader完成bean解析，最终bdHolder持有beanDefinition和beanName，别名 BeanDefinitionHolder bdHolder = delegate.parseBeanDefinitionElement(ele); if (bdHolder != null) /是否有自定义属性需要处理 bdHolder = delegate.decorateBeanDefinitionIfRequired(ele, bdHolder); try / Register the final decorated instance. BeanDefinitionReaderUtils.registerBeanDefinition(bdHolder, getReaderContext().getRegistry(); catch (BeanDefinitionStoreException ex) getReaderContext().error(Failed to register bean definition with name + bdHolder.getBeanName() + , ele, ex); / Send registration event. getReaderContext().fireComponentRegistered(new BeanComponentDefinition(bdHolder); /注册beanDefinition和别名public static void registerBeanDefinition( BeanDefinitionHolder definitionHolder, BeanDefinitionRegistry registry) throws BeanDefinitionStoreException / Register bean definition under primary name. String beanName = definitionHolder.getBeanName(); registry.registerBeanDefinition(beanName, definitionHolder.getBeanDefinition(); / Register aliases for bean name, if any. String aliases = definitionHolder.getAliases(); if (aliases != null) for (String aliase : aliases) registry.registerAlias(beanName, aliase); delegate-parseBeanDefinitionElement(ele)/BeanDefinitionParserDelegatepublic BeanDefinitionHolder parseBeanDefinitionElement(Element ele) return parseBeanDefinitionElement(ele, null);public BeanDefinitionHolder parseBeanDefinitionElement(Element ele, BeanDefinition containingBean) /bean的id和name属性 String id = ele.getAttribute(ID_ATTRIBUTE); String nameAttr = ele.getAttribute(NAME_ATTRIBUTE); /name多个的情况，放入别名 List aliases = new ArrayList(); if (StringUtils.hasLength(nameAttr) String nameArr = StringUtils.tokenizeToStringArray(nameAttr, MULTI_VALUE_ATTRIBUTE_DELIMITERS); aliases.addAll(Arrays.asList(nameArr); String beanName = id; if (!StringUtils.hasText(beanName) & !aliases.isEmpty() beanName = aliases.remove(0); if (logger.isDebugEnabled() logger.debug(No XML id specified - using + beanName + as bean name and + aliases + as aliases); if (containingBean = null) /检查名称是否用过，会有Set存储用过的名称 checkNameUniqueness(beanName, aliases, ele); /解析bean的element成最终的beanDefinition AbstractBeanDefinition beanDefinition = parseBeanDefinitionElement(ele, beanName, containingBean); if (beanDefinition != null) /名称不存在就spring生成一个 if (!StringUtils.hasText(beanName) try if (containingBean != null) beanName = BeanDefinitionReaderUtils.generateBeanName( beanDefinition, this.readerContext.getRegistry(), true); else beanName = this.readerContext.generateBeanName(beanDefinition); / Register an alias for the plain bean class name, if still possible, / if the generator returned the class name plus a suffix. / This is expected for Spring 1