解析mvc:interceptors节点
观察下InterceptorsBeanDefinitionParser的源码备注
/**
* {@link org.springframework.beans.factory.xml.BeanDefinitionParser} that parses a
* {@code interceptors} element to register a set of {@link MappedInterceptor} definitions.
*
* @author Keith Donald
* @since 3.0
*/
从官方注释可知,此解析器的作用是解析mvc:interceptors
节点并注册成MappedInterceptors
Definition集合
mvc:interceptors的配置使用
<!-- 拦截器设置 -->
<mvc:interceptors>
<mvc:interceptor>
<mvc:mapping path="/**"/>
<!-- 静态资源不拦截 -->
<mvc:exclude-mapping path="/mobile/**"/>
<mvc:exclude-mapping path="/pc/**"/>
<!-- 主页不拦截 -->
<!-- 特殊user资源获取不拦截 -->
<bean class="com.du.wx.interceptor.UserInterceptor" />
</mvc:interceptor>
</mvc:interceptors>
InterceptorsBeanDefinitionParser#parse
直接观察公用接口方法parse()
,源码奉上
@Override
public BeanDefinition parse(Element element, ParserContext parserContext) {
//CompositeComponentDefinition表示其可以装载多个ComponentDefinition
CompositeComponentDefinition compDefinition = new CompositeComponentDefinition(element.getTagName(), parserContext.extractSource(element));
parserContext.pushContainingComponent(compDefinition);
//允许mvc:interceptors拥有path-matcher属性,表示 路径匹配解析器
RuntimeBeanReference pathMatcherRef = null;
if (element.hasAttribute("path-matcher")) {
pathMatcherRef = new RuntimeBeanReference(element.getAttribute("path-matcher"));
}
//查询mvc:interceptors节点下的bean/ref/interceptor标签
List<Element> interceptors = DomUtils.getChildElementsByTagName(element, "bean", "ref", "interceptor");
for (Element interceptor : interceptors) {
//采用MappedInterceptor作为beanClass
RootBeanDefinition mappedInterceptorDef = new RootBeanDefinition(MappedInterceptor.class);
mappedInterceptorDef.setSource(parserContext.extractSource(interceptor));
mappedInterceptorDef.setRole(BeanDefinition.ROLE_INFRASTRUCTURE);
ManagedList<String> includePatterns = null;
ManagedList<String> excludePatterns = null;
Object interceptorBean;
//解析mvc:interceptor节点
if ("interceptor".equals(interceptor.getLocalName())) {
//解析mvc:mapping节点中的path属性,保存里面的拦截路径集合
includePatterns = getIncludePatterns(interceptor, "mapping");
//解析mvc:exclude-mapping节点中的path属性,保存里面的放行路径集合
excludePatterns = getIncludePatterns(interceptor, "exclude-mapping");
//解析bean标签/ref标签,并封装成beanDefinition
Element beanElem = DomUtils.getChildElementsByTagName(interceptor, "bean", "ref").get(0);
interceptorBean = parserContext.getDelegate().parsePropertySubElement(beanElem, null);
}
else {
//解析bean标签/ref标签,并封装成beanDefinition
interceptorBean = parserContext.getDelegate().parsePropertySubElement(interceptor, null);
}
//MappedInterceptor类的构造函数可接受三个参数
/**
**public MappedInterceptor(String[] includePatterns, String[] excludePatterns, HandlerInterceptor interceptor)
**
*/
mappedInterceptorDef.getConstructorArgumentValues().addIndexedArgumentValue(0, includePatterns);
mappedInterceptorDef.getConstructorArgumentValues().addIndexedArgumentValue(1, excludePatterns);
mappedInterceptorDef.getConstructorArgumentValues().addIndexedArgumentValue(2, interceptorBean);
//为MappedInterceptor添加pathMatcher属性
if (pathMatcherRef != null) {
mappedInterceptorDef.getPropertyValues().add("pathMatcher", pathMatcherRef);
}
//保存到spring的bean工厂中
String beanName = parserContext.getReaderContext().registerWithGeneratedName(mappedInterceptorDef);
parserContext.registerComponent(new BeanComponentDefinition(mappedInterceptorDef, beanName));
}
parserContext.popAndRegisterContainingComponent();
return null;
}
小结
- 解析
mvc:interceptors
,其会封装为MappedInterceptor
类,进而保存
- 拦截路径匹配集合
includePatterns
- 不拦截路径匹配集合
excludePatterns
- 拦截处理器
interceptor
,其必须是HandlerInterceptor
的实现类- 路径匹配处理器,如果
mvc:interceptors
设定了path-matcher
属性,默认为AntPathMatcher
MappedInterceptor
其内部包含了HandlerInterceptor
集合,并添加了路径的映射属性。对匹配的路径调用相应的HandlerInterceptors
mvc:interceptors
注册的拦截器在AbstractHandlerMapping
类中通过matches()
方法被调用,具体调用见Springmvc源码