大家可以去spring-beans.jar包里的META-INF/spring.handlers找一找，这个文件打开后，内容如下：
http\://www.springframework.org/schema/c=org.springframework.beans.factory.xml.SimpleConstructorNamespaceHandler http\://www.springframework.org/schema/p=org.springframework.beans.factory.xml.SimplePropertyNamespaceHandler http\://www.springframework.org/schema/util=org.springframework.beans.factory.xml.UtilNamespaceHandler也可以再去spring-context.jar里找找，里面也有这个文件：
http\://www.springframework.org/schema/context=org.springframework.context.config.ContextNamespaceHandler http\://www.springframework.org/schema/jee=org.springframework.ejb.config.JeeNamespaceHandler http\://www.springframework.org/schema/lang=org.springframework.scripting.config.LangNamespaceHandler http\://www.springframework.org/schema/task=org.springframework.scheduling.config.TaskNamespaceHandler http\://www.springframework.org/schema/cache=org.springframework.cache.config.CacheNamespaceHandler我列了个表格：
namespace handlerorg.springframework.beans.factory.xml.SimpleConstructorNamespaceHandler
org.springframework.beans.factory.xml.SimplePropertyNamespaceHandler
org.springframework.beans.factory.xml.UtilNamespaceHandler
org.springframework.context.config.ContextNamespaceHandler
org.springframework.scheduling.config.TaskNamespaceHandler
org.springframework.cache.config.CacheNamespaceHandler
比较重要的，我都列在上面了，剩下的jee/lang，我没用过，不知道大家用过没，先跳过吧。
大家可能也有感到奇怪的地方，怎么没有这个namespace的呢，因为它是默认的，所以在程序里是特殊处理的，一会才到它。
接着看核心逻辑：
DefaultBeanDefinitionDocumentReader#doRegisterBeanDefinitions protected void doRegisterBeanDefinitions(Element root) { BeanDefinitionParserDelegate parent = this.delegate; this.delegate = createHelper(this.readerContext, root, parent); preProcessXml(root); parseBeanDefinitions(root, this.delegate); postProcessXml(root); this.delegate = parent; } BeanDefinitionParserDelegate恩。。。我们已经快疯了，怎么又出来一个类，DefaultBeanDefinitionDocumentReader看来也是觉得自己工作压力太大了吧，这里又弄了个BeanDefinitionParserDelegate。
这个类，没实现什么接口，就是个大杂烩，方法多的一批，主要是进行具体的解析工作，大家可以看看里面定义的字段：
public static final String BEANS_NAMESPACE_URI = "http://www.springframework.org/schema/beans"; public static final String MULTI_VALUE_ATTRIBUTE_DELIMITERS = ",; "; /** * Value of a T/F attribute that represents true. * Anything else represents false. Case seNsItive. */ public static final String TRUE_VALUE = "true"; public static final String FALSE_VALUE = "false"; public static final String DEFAULT_VALUE = "default"; public static final String DESCRIPTION_ELEMENT = "description"; public static final String AUTOWIRE_NO_VALUE = "no"; public static final String AUTOWIRE_BY_NAME_VALUE = "byName"; public static final String AUTOWIRE_BY_TYPE_VALUE = "byType"; public static final String AUTOWIRE_CONSTRUCTOR_VALUE = "constructor"; public static final String AUTOWIRE_AUTODETECT_VALUE = "autodetect"; public static final String DEPENDENCY_CHECK_ALL_ATTRIBUTE_VALUE = "all"; public static final String DEPENDENCY_CHECK_SIMPLE_ATTRIBUTE_VALUE = "simple"; public static final String DEPENDENCY_CHECK_OBJECTS_ATTRIBUTE_VALUE = "objects"; public static final String NAME_ATTRIBUTE = "name"; public static final String BEAN_ELEMENT = "bean"; public static final String META_ELEMENT = "meta"; public static final String ID_ATTRIBUTE = "id"; public static final String PARENT_ATTRIBUTE = "parent"; public static final String CLASS_ATTRIBUTE = "class"; public static final String ABSTRACT_ATTRIBUTE = "abstract"; public static final String SCOPE_ATTRIBUTE = "scope"; public static final String SINGLETON_ATTRIBUTE = "singleton"; public static final String LAZY_INIT_ATTRIBUTE = "lazy-init"; public static final String AUTOWIRE_ATTRIBUTE = "autowire"; public static final String AUTOWIRE_CANDIDATE_ATTRIBUTE = "autowire-candidate"; public static final String PRIMARY_ATTRIBUTE = "primary"; public static final String DEPENDENCY_CHECK_ATTRIBUTE = "dependency-check"; public static final String DEPENDS_ON_ATTRIBUTE = "depends-on"; public static final String INIT_METHOD_ATTRIBUTE = "init-method"; public static final String DESTROY_METHOD_ATTRIBUTE = "destroy-method"; public static final String FACTORY_METHOD_ATTRIBUTE = "factory-method"; public static final String FACTORY_BEAN_ATTRIBUTE = "factory-bean"; public static final String CONSTRUCTOR_ARG_ELEMENT = "constructor-arg"; public static final String INDEX_ATTRIBUTE = "index"; public static final String TYPE_ATTRIBUTE = "type"; public static final String VALUE_TYPE_ATTRIBUTE = "value-type"; public static final String KEY_TYPE_ATTRIBUTE = "key-type"; public static final String PROPERTY_ELEMENT = "property"; public static final String REF_ATTRIBUTE = "ref"; public static final String VALUE_ATTRIBUTE = "value"; public static final String LOOKUP_METHOD_ELEMENT = "lookup-method"; public static final String REPLACED_METHOD_ELEMENT = "replaced-method"; public static final String REPLACER_ATTRIBUTE = "replacer"; public static final String ARG_TYPE_ELEMENT = "arg-type"; public static final String ARG_TYPE_MATCH_ATTRIBUTE = "match"; public static final String REF_ELEMENT = "ref"; public static final String IDREF_ELEMENT = "idref"; public static final String BEAN_REF_ATTRIBUTE = "bean"; public static final String LOCAL_REF_ATTRIBUTE = "local"; ...看出来了么，主要都是xml里面的那些元素的名称。
里面的方法，很多，我们用到了再说。