简单流程图
RequestMappingHandlerMapping的createRequestMappingInfo创建映射
首先获取RequestMapping注解，如果存在就创建一个RequestMappingInfo否则就返回null 。
@Nullable
private RequestMappingInfo createRequestMappingInfo(AnnotatedElement element) {
RequestMapping requestMapping = AnnotatedElementUtils.findMergedAnnotation(element, RequestMapping.class);
RequestCondition<?> condition = (element instanceof Class ?
getCustomTypeCondition((Class<?>) element) : getCustomMethodCondition((Method) element));
return (requestMapping != null ? createRequestMappingInfo(requestMapping, condition) : null);
}
其实就是封装方法的RequestMappingInfo注解的属性啦：
然后是类上的：
combine合并属性
具体怎么合并的细节就不看了。
合并后的结果，我们常用的就是uri拼起来了：
最后放入methodMap返回：
registerHandlerMethod
注册方法，最终是注册到MappingRegistry中的。
@Override
protected void registerHandlerMethod(Object handler, Method method, RequestMappingInfo mapping) {
super.registerHandlerMethod(handler, method, mapping);
updateConsumesCondition(mapping, method);
}
protected void registerHandlerMethod(Object handler, Method method, T mapping) {
this.mappingRegistry.register(mapping, handler, method);
}
MappingRegistry的register
注册各种类型的映射。
private final Map<T, MappingRegistration<T>> registry = new HashMap<>();
private final Map<T, HandlerMethod> mappingLookup = new LinkedHashMap<>();
private final MultiValueMap<String, T> urlLookup = new LinkedMultiValueMap<>();
private final Map<String, List<HandlerMethod>> nameLookup = new ConcurrentHashMap<>();
public void register(T mapping, Object handler, Method method) {
...
this.readWriteLock.writeLock().lock();
try {
HandlerMethod handlerMethod = createHandlerMethod(handler, method);//创建HandlerMethod
validateMethodMapping(handlerMethod, mapping);//验证唯一性
this.mappingLookup.put(mapping, handlerMethod);//方法映射，放入mappingLookup
List<String> directUrls = getDirectUrls(mapping);
for (String url : directUrls) {
this.urlLookup.add(url, mapping);//url映射，放入mappingLookup，可以多对一
}
String name = null;
if (getNamingStrategy() != null) {
name = getNamingStrategy().getName(handlerMethod, mapping);
addMappingName(name, handlerMethod);//名字映射，name为类名大写字母+#+方法名，比如UserController的getUser方法就是UC#getUser
}
...
this.registry.put(mapping, new MappingRegistration<>(mapping, handlerMethod, directUrls, name));//封装成MappingRegistration放入registry
}
finally {
this.readWriteLock.writeLock().unlock();
}
}
AbstractHandlerMethodMapping的createHandlerMethod
根据是处理器是String还是对象类型进行不同的HandlerMethod封装，一般初始化的时候还没有实例，只是名字。
protected HandlerMethod createHandlerMethod(Object handler, Method method) {
if (handler instanceof String) {
//如果是bean名字
return new HandlerMethod((String) handler,
obtainApplicationContext().getAutowireCapableBeanFactory(), method);
}
return new HandlerMethod(handler, method);
}
处理器名字创建：
内部会获取名字对应的类型，进行方法参数信息的封装和ResponseStatus注解相关处理。
MappingRegistry的validateMethodMapping检查唯一性
如果uri映射HandlerMethod已经存在，且不是同一个HandlerMethod要报异常。
private void validateMethodMapping(HandlerMethod handlerMethod, T mapping) {
// Assert that the supplied mapping is unique.
HandlerMethod existingHandlerMethod = this.mappingLookup.get(mapping);
if (existingHandlerMethod != null && !existingHandlerMethod.equals(handlerMethod)) {
throw new IllegalStateException(
"Ambiguous mapping. Cannot map '" + handlerMethod.getBean() + "' method \n" +
handlerMethod + "\nto " + mapping + ": There is already '" +
existingHandlerMethod.getBean() + "' bean method\n" + existingHandlerMethod + " mapped.");
}
}
好了，今天就到这里了，希望对学习理解有帮助，大神看见勿喷，仅为自己的学习理解，能力有限，请多包涵。