默认标签的解析过程（三）parseDefaultElement

    private void parseDefaultElement(Element ele, BeanDefinitionParserDelegate delegate) {
        if (delegate.nodeNameEquals(ele, IMPORT_ELEMENT)) {
            importBeanDefinitionResource(ele);
        }
        else if (delegate.nodeNameEquals(ele, ALIAS_ELEMENT)) {
            processAliasRegistration(ele);
        }
        else if (delegate.nodeNameEquals(ele, BEAN_ELEMENT)) {
            processBeanDefinition(ele, delegate);
        }
        else if (delegate.nodeNameEquals(ele, NESTED_BEANS_ELEMENT)) {
            // recurse
            doRegisterBeanDefinitions(ele);
        }
    }

可以看出主要对（import,  alias, bean, beans进行解析）

IMPORT_ELEMENT

ALIAS_ELEMENT

BEAN_ELEMENT

NESTED_BEANS_ELEMENT
在上一篇文章DefaultListableBeanFactory只是保存一些bean解析出后的信息的注册基本信息到

beanDefinitionMap 

/** Resolver to use for checking if a bean definition is an autowire candidate */
	private AutowireCandidateResolver autowireCandidateResolver = new SimpleAutowireCandidateResolver();

	/** Map from dependency type to corresponding autowired value */
	private final Map<Class<?>, Object> resolvableDependencies = new HashMap<Class<?>, Object>(16);

	/** Map of bean definition objects, keyed by bean。 name BeanDefinition主要是保存Bean 的名字，class 依赖等待信息*/ 
private final Map<String, BeanDefinition> beanDefinitionMap = new ConcurrentHashMap<String, BeanDefinition>(64); 
/** Map of singleton bean names keyed by bean class */ 
private final Map<Class<?>, String[]> singletonBeanNamesByType = new ConcurrentHashMap<Class<?>, String[]>(64); 
/** Map of non-singleton bean names keyed by bean class */ 
private final Map<Class<?>, String[]> nonSingletonBeanNamesByType = new ConcurrentHashMap<Class<?>, String[]>(64); 
/** List of bean definition names, in registration order */ 
private final List<String> beanDefinitionNames = new ArrayList<String>();

　Bean解析：

    /**
     * Process the given bean element, parsing the bean definition
     * and registering it with the registry.
     */
    protected void processBeanDefinition(Element ele, BeanDefinitionParserDelegate delegate) {
        BeanDefinitionHolder bdHolder = delegate.parseBeanDefinitionElement(ele);//根据ele解析出所包含的所有信息
        if (bdHolder != null) {
            bdHolder = delegate.decorateBeanDefinitionIfRequired(ele, bdHolder);
            try {
                // Register the final decorated instance.注册bdHold到beanDefinationMap
                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));
        }
    }

/**
     * Parses the supplied <code>&lt;bean&gt;</code> element. May return <code>null</code>
     * if there were errors during parse. Errors are reported to the
     * {@link org.springframework.beans.factory.parsing.ProblemReporter}.
     */
    public BeanDefinitionHolder parseBeanDefinitionElement(Element ele) {
        return parseBeanDefinitionElement(ele, null);
    }

    /**
     * Parses the supplied <code>&lt;bean&gt;</code> element. May return <code>null</code>
     * if there were errors during parse. Errors are reported to the
     * {@link org.springframework.beans.factory.parsing.ProblemReporter}.
     */
    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;
    }

/**
     * Parse the bean definition itself, without regard to name or aliases. May return
     * <code>null</code> if problems occurred during the parsing of the bean definition.
     */
    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); //返回GenericBeanDefinition 用于承载beanDefi

            parseBeanDefinitionAttributes(ele, beanName, containingBean, bd); //解析各种attr到bd
            bd.setDescription(DomUtils.getChildElementValueByTagName(ele, DESCRIPTION_ELEMENT));

            parseMetaElements(ele, bd);//<bean><meta..到bd
            parseLookupOverrideSubElements(ele, bd.getMethodOverrides());  //<bean><lookup-method...到 bd
            parseReplacedMethodSubElements(ele, bd.getMethodOverrides());//<bean><replaced-method 到bd 动态替换bean里面的方法

            parseConstructorArgElements(ele, bd);//<bean><constructor-arg... 到bd
            parsePropertyElements(ele, bd);  //<bean><property....到bd
            parseQualifierElements(ele, bd); //<bean><qualifier 到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;
    }

alians 也与bean类似