SpringMVC源码解读之HandlerMapping

// HandlerMapping
package org.springframework.web.servlet;
public interface HandlerMapping {
HandlerExecutionChain getHandler(HttpServletRequest request) throws Exception;
}

package org.springframework.web.servlet.handler;
public abstract class AbstractHandlerMapping extends WebApplicationObjectSupport
implements HandlerMapping, Ordered {
// ...
}

// AbstractHandlerMapping
// order赋了最大值,优先级是最小的
private int order = Integer.MAX_VALUE; // default: same as non-Ordered
// 默认的Handler,这边使用的Obejct,子类实现的时候,使用HandlerMethod,HandlerExecutionChain等
private Object defaultHandler;
// url计算的辅助类
private UrlPathHelper urlPathHelper = new UrlPathHelper();
// 基于ant进行path匹配,解决如/books/{id}场景
private PathMatcher pathMatcher = new AntPathMatcher();
// 拦截器配置:,HandlerMapping属性设置;,extendInterceptors设置
private final List<Object> interceptors = new ArrayList<Object>();
// 从interceptors中解析得到,直接添加给全部handler
private final List<HandlerInterceptor> adaptedInterceptors = new ArrayList<HandlerInterceptor>();
// 使用前需要跟url进行匹配,匹配通过才会使用
private final List<MappedInterceptor> mappedInterceptors = new ArrayList<MappedInterceptor>(); 

// AbstractHandlerMapping
@Override
protected void initApplicationContext() throws BeansException {
extendInterceptors(this.interceptors);
detectMappedInterceptors(this.mappedInterceptors);
initInterceptors();
}
/**
* 提供给子类扩展拦截器,可惜都没有使用
*/
protected void extendInterceptors(List<Object> interceptors) {
}
/**
* 扫描应用下的MappedInterceptor,并添加到mappedInterceptors
*/
protected void detectMappedInterceptors(List<MappedInterceptor> mappedInterceptors) {
mappedInterceptors.addAll(
BeanFactoryUtils.beansOfTypeIncludingAncestors(
getApplicationContext(),MappedInterceptor.class, true, false).values());
}
/**
* 归集MappedInterceptor,并适配HandlerInterceptor和WebRequestInterceptor
*/
protected void initInterceptors() {
if (!this.interceptors.isEmpty()) {
for (int i = ; i < this.interceptors.size(); i++) {
Object interceptor = this.interceptors.get(i);
if (interceptor == null) {
throw new IllegalArgumentException("Entry number " + i + " in interceptors array is null");
}
if (interceptor instanceof MappedInterceptor) {
mappedInterceptors.add((MappedInterceptor) interceptor);
}
else {
adaptedInterceptors.add(adaptInterceptor(interceptor));
}
}
}
}
protected HandlerInterceptor adaptInterceptor(Object interceptor) {
if (interceptor instanceof HandlerInterceptor) {
return (HandlerInterceptor) interceptor;
}
else if (interceptor instanceof WebRequestInterceptor) {
return new WebRequestHandlerInterceptorAdapter((WebRequestInterceptor) interceptor);
}
else {
throw new IllegalArgumentException("Interceptor type not supported: " + interceptor.getClass().getName());
}
}

// AbstractHandlerMapping
public final HandlerExecutionChain getHandler(HttpServletRequest request) throws Exception {
Object handler = getHandlerInternal(request);
if (handler == null) {
handler = getDefaultHandler();
}
if (handler == null) {
return null;
}
// Bean name or resolved handler?
if (handler instanceof String) {
String handlerName = (String) handler;
handler = getApplicationContext().getBean(handlerName);
}
return getHandlerExecutionChain(handler, request);
}
protected abstract Object getHandlerInternal(HttpServletRequest request) throws Exception; 

// AbstractHandlerMapping
protected HandlerExecutionChain getHandlerExecutionChain(Object handler, HttpServletRequest request) {
HandlerExecutionChain chain =
(handler instanceof HandlerExecutionChain) ?
(HandlerExecutionChain) handler : new HandlerExecutionChain(handler);
chain.addInterceptors(getAdaptedInterceptors());
String lookupPath = urlPathHelper.getLookupPathForRequest(request);
for (MappedInterceptor mappedInterceptor : mappedInterceptors) {
if (mappedInterceptor.matches(lookupPath, pathMatcher)) {
chain.addInterceptor(mappedInterceptor.getInterceptor());
}
}
return chain;
} 

protected void registerHandler(String[] urlPaths, String beanName) throws BeansException, IllegalStateException { }
protected void registerHandler(String urlPath, Object handler) throws BeansException, IllegalStateException { } 

protected Object getHandlerInternal(HttpServletRequest request) throws Exception {}
// 根据url查找handler
protected Object lookupHandler(String urlPath, HttpServletRequest request) throws Exception {}
// 校验handler
protected void validateHandler(Object handler, HttpServletRequest request) throws Exception {}
// 封装拦截器到HandlerExecutionChain
protected Object buildPathExposingHandler(Object rawHandler, String bestMatchingPattern,
String pathWithinMapping, Map<String, String> uriTemplateVariables) {} 

@Override
public void initApplicationContext() throws ApplicationContextException {
super.initApplicationContext();
detectHandlers();
}
protected void detectHandlers() throws BeansException {
// ...
}
/**
* Determine the URLs for the given handler bean.
* 钩子而已
*/
protected abstract String[] determineUrlsForHandler(String beanName); 

AbstractControllerUrlHandlerMapping,这边一样不展开,具体移步<SpringMVC源码解读 - HandlerMapping - AbstractDetectingUrlHandlerMapping系列初始化>

@Override
protected String[] determineUrlsForHandler(String beanName) {
Class beanClass = getApplicationContext().getType(beanName);
if (isEligibleForMapping(beanName, beanClass)) {
return buildUrlsForHandler(beanName, beanClass);
}
else {
return null;
}
}
protected boolean isEligibleForMapping(String beanName, Class beanClass) {}
protected boolean isControllerType(Class beanClass) {}
protected abstract String[] buildUrlsForHandler(String beanName, Class beanClass); 

ControllerBeanNameHandlerMapping和ControllerClassNameHandlerMapping 直接看源码吧,或者移步<SpringMVC源码解读 - HandlerMapping - AbstractDetectingUrlHandlerMapping系列初始化>