XML bean def conf 读取
BeanDefinitionReader
XmlBeanDefinitionReader 遵循 BeanDefinitionReader (其他非Java Config 的bean def reader 也遵循这个interface)。
BeanDefinitionReader 持有BeanDefinitionRegistry的ref，接受Resource object，读取解析后存入BeanDefinitionRegistry
//BeanDefinitionReader
BeanDefinitionRegistry getRegistry();
ResourceLoader getResourceLoader();
ClassLoader getBeanClassLoader();
BeanNameGenerator getBeanNameGenerator();
int loadBeanDefinitions(Resource... resources);
int loadBeanDefinitions(String... locations);
AbstractBeanDefinitionReader
接受外部传入registry。一般传入AppilcationContext。由于Application 亦实现了ResourceLoader接口，所以实际是把registry 和resource loader delete给了ApplicationContext。
protected AbstractBeanDefinitionReader(BeanDefinitionRegistry registry) {
Assert.notNull(registry, "BeanDefinitionRegistry must not be null");
this.registry = registry;
// Determine ResourceLoader to use.
if (this.registry instanceof ResourceLoader) {
this.resourceLoader = (ResourceLoader) this.registry;
}
else {
this.resourceLoader = new PathMatchingResourcePatternResolver();
}
// Inherit Environment if possible
if (this.registry instanceof EnvironmentCapable) {
this.environment = ((EnvironmentCapable) this.registry).getEnvironment();
}
else {
this.environment = new StandardEnvironment();
}
}
AbstractBeanDefinitionReader 实现了从传入的location读取Resource 的逻辑，实际处理Resource 交由子类处理
public int loadBeanDefinitions(String location, @Nullable Set<Resource> actualResources) {
...
Resource[] resources = ((ResourcePatternResolver) resourceLoader).getResources(location);
int loadCount = loadBeanDefinitions(resources);
...
}
XmlBeanDefinitionReader
loadBeanDefinitions(Resource resource) 顺序如下，先读取resource 成 xml document, 再逐个解析xml document 的元素。
-
loadBeanDefinitions(EncodedResource encodedResource)从Resource获取InputStream。调用doLoadBeanDefinitions(inputSource, encodedResource.getResource()) -
Document doc = doLoadDocument(inputSource, resource)使用DefaultDocumentLoader加载XML 为Document
Document doc = doLoadDocument(inputSource, resource);
return registerBeanDefinitions(doc, resource);
-
registerBeanDefinitions(Document doc, Resource resource)使用DefaultBeanDefinitionDocumentReader读取XML doc
BeanDefinitionDocumentReader documentReader = createBeanDefinitionDocumentReader();
documentReader.registerBeanDefinitions(doc, createReaderContext(resource));
- DocumentReader 读取非自定义的bean def。实际bean读取工作被delegate 给
BeanDefinitionParserDelegate
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);
}
}
-
BeanDefinitionParserDelegate里面就是针对XML doc 元素的解析，下略。
