第一步从spring的容器刷新开始

org.springframework.context.support.AbstractApplicationContext#refresh
    ConfigurableListableBeanFactory beanFactory = obtainFreshBeanFactory();
        org.springframework.context.support.AbstractApplicationContext#obtainFreshBeanFactory
        org.springframework.context.support.AbstractRefreshableApplicationContext#refreshBeanFactory
            loadBeanDefinitions(beanFactory);

    // Create a new XmlBeanDefinitionReader for the given BeanFactory.
        XmlBeanDefinitionReader beanDefinitionReader = new XmlBeanDefinitionReader(beanFactory);
        beanDefinitionReader.setEnvironment(this.getEnvironment());
        beanDefinitionReader.setResourceLoader(this);
        beanDefinitionReader.setEntityResolver(new ResourceEntityResolver(this));
        initBeanDefinitionReader(beanDefinitionReader);
        // 继续加载bean
        loadBeanDefinitions(beanDefinitionReader);
org.springframework.web.context.support.XmlWebApplicationContext#loadBeanDefinitions(org.springframework.beans.factory.xml.XmlBeanDefinitionReader)

    protected void loadBeanDefinitions(XmlBeanDefinitionReader reader) throws IOException {
        String[] configLocations = getConfigLocations();
        if (configLocations != null) {
                // 继续加载
                reader.loadBeanDefinitions(configLocation);
            }
        }
    }

    // location  传入xml文件地址
    public int loadBeanDefinitions(String location) throws BeanDefinitionStoreException {
        return loadBeanDefinitions(location, null);
    }

解析XML并注册bean

org.springframework.beans.factory.xml.XmlBeanDefinitionReader#registerBeanDefinitions

    public int registerBeanDefinitions(Document doc, Resource resource) throws BeanDefinitionStoreException {
        BeanDefinitionDocumentReader documentReader = createBeanDefinitionDocumentReader();
        documentReader.setEnvironment(this.getEnvironment());
        // 获取当前容器中存在多少bean
        int countBefore = getRegistry().getBeanDefinitionCount();
        //解析xml把bean注册到容器中
        documentReader.registerBeanDefinitions(doc, createReaderContext(resource));
        // 返回容器中注册进来多少个bean
        return getRegistry().getBeanDefinitionCount() - countBefore;
    }

org.springframework.beans.factory.xml.DefaultBeanDefinitionDocumentReader#registerBeanDefinitions

    public void registerBeanDefinitions(Document doc, XmlReaderContext readerContext) {
        this.readerContext = readerContext;

        logger.debug("Loading bean definitions");
        Element root = doc.getDocumentElement();

        doRegisterBeanDefinitions(root);
    }

org.springframework.beans.factory.xml.DefaultBeanDefinitionDocumentReader#doRegisterBeanDefinitions

    protected void doRegisterBeanDefinitions(Element root) {
        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 <beans> elements will cause recursion in this method. In
        // order to propagate and preserve <beans> 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;
        this.delegate = createHelper(readerContext, root, parent);

        preProcessXml(root);
        //解析并注册
        parseBeanDefinitions(root, this.delegate);
        postProcessXml(root);

        this.delegate = parent;
    }

委托下面的类处理xml数据信息
org.springframework.beans.factory.xml.BeanDefinitionParserDelegate

org.springframework.beans.factory.xml.DefaultBeanDefinitionDocumentReader#parseBeanDefinitions

    protected void parseBeanDefinitions(Element root, BeanDefinitionParserDelegate delegate) {
        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)) {
                        parseDefaultElement(ele, delegate);
                    }
                    else {
                        delegate.parseCustomElement(ele);
                    }
                }
            }
        }
        else {
            delegate.parseCustomElement(root);
        }
    }

a

org.springframework.beans.factory.xml.BeanDefinitionParserDelegate#isDefaultNamespace(org.w3c.dom.Node)
    public boolean isDefaultNamespace(Node node) {
        return isDefaultNamespace(getNamespaceURI(node));
    }
    public boolean isDefaultNamespace(String namespaceUri) {
        return (!StringUtils.hasLength(namespaceUri) || BEANS_NAMESPACE_URI.equals(namespaceUri));
    }


org.springframework.beans.factory.xml.BeanDefinitionParserDelegate#nodeNameEquals
    public boolean nodeNameEquals(Node node, String desiredName) {
        return desiredName.equals(node.getNodeName()) || desiredName.equals(getLocalName(node));
    }




org.springframework.beans.factory.xml.DefaultBeanDefinitionDocumentReader#parseDefaultElement
// 这个位置是专门用来处理bean注册的
private void parseDefaultElement(Element ele, BeanDefinitionParserDelegate delegate) {
        //节点是import的注册处理
        if (delegate.nodeNameEquals(ele, IMPORT_ELEMENT)) {
            importBeanDefinitionResource(ele);
        }
        //节点是alias的注册处理
        else if (delegate.nodeNameEquals(ele, ALIAS_ELEMENT)) {
            processAliasRegistration(ele);
        }
        //节点是bean的注册处理
        else if (delegate.nodeNameEquals(ele, BEAN_ELEMENT)) {
            processBeanDefinition(ele, delegate);
        }
        //节点是beans的注册处理
        else if (delegate.nodeNameEquals(ele, NESTED_BEANS_ELEMENT)) {
            // recurse
            doRegisterBeanDefinitions(ele);
        }
    }


org.springframework.beans.factory.xml.DefaultBeanDefinitionDocumentReader#processBeanDefinition

    protected void processBeanDefinition(Element ele, BeanDefinitionParserDelegate delegate) {
        //解析xml  解析过程下文详解
        BeanDefinitionHolder bdHolder = delegate.parseBeanDefinitionElement(ele);
        if (bdHolder != null) {
            bdHolder = delegate.decorateBeanDefinitionIfRequired(ele, bdHolder);
            try {
                // Register the final decorated instance.
                //注册bean的装饰对象
                BeanDefinitionReaderUtils.registerBeanDefinition(bdHolder, getReaderContext().getRegistry());
            }
            catch (BeanDefinitionStoreException ex) {
                getReaderContext().error("Failed to register bean definition with name '" +
                        bdHolder.getBeanName() + "'", ele, ex);
            }
            // Send registration event.
            // 注册事件
            getReaderContext().fireComponentRegistered(new BeanComponentDefinition(bdHolder));
        }
    }

org.springframework.beans.factory.support.BeanDefinitionReaderUtils#registerBeanDefinition

    public static void registerBeanDefinition(
            BeanDefinitionHolder definitionHolder, BeanDefinitionRegistry registry)
            throws BeanDefinitionStoreException {

        // Register bean definition under primary name.
        String beanName = definitionHolder.getBeanName();
        //真正的把bean注册到容器
        registry.registerBeanDefinition(beanName, definitionHolder.getBeanDefinition());

        // Register aliases for bean name, if any.
        //注册别名
        String[] aliases = definitionHolder.getAliases();
        if (aliases != null) {
            for (String aliase : aliases) {
                registry.registerAlias(beanName, aliase);
            }
        }
    }


//注册的详细处理
org.springframework.beans.factory.support.DefaultListableBeanFactory#registerBeanDefinition
    public void registerBeanDefinition(String beanName, BeanDefinition beanDefinition)
            throws BeanDefinitionStoreException {

        Assert.hasText(beanName, "Bean name must not be empty");
        Assert.notNull(beanDefinition, "BeanDefinition must not be null");

        if (beanDefinition instanceof AbstractBeanDefinition) {
            try {
                ((AbstractBeanDefinition) beanDefinition).validate();
            }
            catch (BeanDefinitionValidationException ex) {
                throw new BeanDefinitionStoreException(beanDefinition.getResourceDescription(), beanName,
                        "Validation of bean definition failed", ex);
            }
        }

        synchronized (this.beanDefinitionMap) {
            Object oldBeanDefinition = this.beanDefinitionMap.get(beanName);
            if (oldBeanDefinition != null) {
                if (!this.allowBeanDefinitionOverriding) {
                    throw new BeanDefinitionStoreException(beanDefinition.getResourceDescription(), beanName,
                            "Cannot register bean definition [" + beanDefinition + "] for bean '" + beanName +
                            "': There is already [" + oldBeanDefinition + "] bound.");
                }
                else {
                    if (this.logger.isInfoEnabled()) {
                        this.logger.info("Overriding bean definition for bean '" + beanName +
                                "': replacing [" + oldBeanDefinition + "] with [" + beanDefinition + "]");
                    }
                }
            }
            else {
                this.beanDefinitionNames.add(beanName);
                this.frozenBeanDefinitionNames = null;
            }
            this.beanDefinitionMap.put(beanName, beanDefinition);

            resetBeanDefinition(beanName);
        }
    }

b

org.springframework.beans.factory.xml.BeanDefinitionParserDelegate#parseCustomElement(org.w3c.dom.Element)

public BeanDefinition parseCustomElement(Element ele) {
        return parseCustomElement(ele, null);
    }

    public BeanDefinition parseCustomElement(Element ele, BeanDefinition containingBd) {
        String namespaceUri = getNamespaceURI(ele);
        NamespaceHandler handler = this.readerContext.getNamespaceHandlerResolver().resolve(namespaceUri);
        if (handler == null) {
            error("Unable to locate Spring NamespaceHandler for XML schema namespace [" + namespaceUri + "]", ele);
            return null;
        }
        return handler.parse(ele, new ParserContext(this.readerContext, this, containingBd));
    }

解析数据信息过程

org.springframework.beans.factory.xml.BeanDefinitionParserDelegate#parseBeanDefinitionElement(org.w3c.dom.Element)


public BeanDefinitionHolder parseBeanDefinitionElement(Element ele, BeanDefinition containingBean) {
        String id = ele.getAttribute(ID_ATTRIBUTE);
        String nameAttr = ele.getAttribute(NAME_ATTRIBUTE);

        List<String> aliases = new ArrayList<String>();
        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) {
            checkNameUniqueness(beanName, aliases, ele);
        }

        AbstractBeanDefinition beanDefinition = parseBeanDefinitionElement(ele, beanName, containingBean);
        if (beanDefinition != null) {
            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 1.2/2.0 backwards compatibility.
                        String beanClassName = beanDefinition.getBeanClassName();
                        if (beanClassName != null &&
                                beanName.startsWith(beanClassName) && beanName.length() > beanClassName.length() &&
                                !this.readerContext.getRegistry().isBeanNameInUse(beanClassName)) {
                            aliases.add(beanClassName);
                        }
                    }
                    if (logger.isDebugEnabled()) {
                        logger.debug("Neither XML 'id' nor 'name' specified - " +
                                "using generated bean name [" + beanName + "]");
                    }
                }
                catch (Exception ex) {
                    error(ex.getMessage(), ele);
                    return null;
                }
            }
            String[] aliasesArray = StringUtils.toStringArray(aliases);
            return new BeanDefinitionHolder(beanDefinition, beanName, aliasesArray);
        }

        return null;
    }

public AbstractBeanDefinition parseBeanDefinitionElement(
            Element ele, String beanName, BeanDefinition containingBean) {

        this.parseState.push(new BeanEntry(beanName));

        String className = null;
        if (ele.hasAttribute(CLASS_ATTRIBUTE)) {
            className = ele.getAttribute(CLASS_ATTRIBUTE).trim();
        }

        try {
            String parent = null;
            if (ele.hasAttribute(PARENT_ATTRIBUTE)) {
                parent = ele.getAttribute(PARENT_ATTRIBUTE);
            }
            AbstractBeanDefinition bd = createBeanDefinition(className, parent);

            parseBeanDefinitionAttributes(ele, beanName, containingBean, bd);
            bd.setDescription(DomUtils.getChildElementValueByTagName(ele, DESCRIPTION_ELEMENT));

            parseMetaElements(ele, bd);
            parseLookupOverrideSubElements(ele, bd.getMethodOverrides());
            parseReplacedMethodSubElements(ele, bd.getMethodOverrides());

            parseConstructorArgElements(ele, bd);
            parsePropertyElements(ele, bd);
            parseQualifierElements(ele, bd);

            bd.setResource(this.readerContext.getResource());
            bd.setSource(extractSource(ele));

            return bd;
        }
        catch (ClassNotFoundException ex) {
            error("Bean class [" + className + "] not found", ele, ex);
        }
        catch (NoClassDefFoundError err) {
            error("Class that bean class [" + className + "] depends on not found", ele, err);
        }
        catch (Throwable ex) {
            error("Unexpected failure during bean definition parsing", ele, ex);
        }
        finally {
            this.parseState.pop();
        }

        return null;
    }

bean的封装

BeanDefinitionHolder
    //bean封装对象
    private final BeanDefinition beanDefinition;

    //bean 配置名 ID
    private final String beanName;
    // bean的别名组
    private final String[] aliases;
BeanDefinition