spring requestMapping注解将url映射到controller方法
1url 映射的handler（即controller） 会放在RequestMappingHandlerMapping 类中， RequestMappingHandlerMapping的父类是AbstractHandlerMethodMapping AbstractHandlerMethodMapping 实现了InitializingBean
- RequestMappingHandlerMapping 覆盖了父类AbstractHandlerMethodMapping 的afterPropertiesSet 方法
@Override
public void afterPropertiesSet() {
this.config = new RequestMappingInfo.BuilderConfiguration();
this.config.setUrlPathHelper(getUrlPathHelper());
this.config.setPathMatcher(getPathMatcher());
this.config.setSuffixPatternMatch(this.useSuffixPatternMatch);
this.config.setTrailingSlashMatch(this.useTrailingSlashMatch);
this.config.setRegisteredSuffixPatternMatch(this.useRegisteredSuffixPatternMatch);
this.config.setContentNegotiationManager(getContentNegotiationManager());
// 调用父类的afterPropertiesSet 方法
super.afterPropertiesSet();
}
AbstractHandlerMethodMapping 的afterPropertiesSet 方法
@Override
public void afterPropertiesSet() {
initHandlerMethods();
}
- 初始化handler 方法
protected void initHandlerMethods() {
// 遍历所有bean
for (String beanName : getCandidateBeanNames()) {
if (!beanName.startsWith(SCOPED_TARGET_NAME_PREFIX)) {
// 处理候选bean
processCandidateBean(beanName);
}
}
handlerMethodsInitialized(getHandlerMethods());
}
- 处理候选bean
protected void processCandidateBean(String beanName) {
Class<?> beanType = null;
try {
beanType = obtainApplicationContext().getType(beanName);
}
catch (Throwable ex) {
// An unresolvable bean type, probably from a lazy bean - lets ignore it.
if (logger.isTraceEnabled()) {
logger.trace("Could not resolve type for bean " + beanName + "", ex);
}
}
if (beanType != null && isHandler(beanType)) {
// 检测handler 方法（即controller的method）
detectHandlerMethods(beanName);
}
}
- 检测handler 方法（即controller的method）
protected void detectHandlerMethods(Object handler) {
Class<?> handlerType = (handler instanceof String ?
obtainApplicationContext().getType((String) handler) : handler.getClass());
if (handlerType != null) {
Class<?> userType = ClassUtils.getUserClass(handlerType);
Map<Method, T> methods = MethodIntrospector.selectMethods(userType,
(MethodIntrospector.MetadataLookup<T>) method -> {
try {
return getMappingForMethod(method, userType);
}
catch (Throwable ex) {
throw new IllegalStateException("Invalid mapping on handler class [" +
userType.getName() + "]: " + method, ex);
}
});
if (logger.isTraceEnabled()) {
logger.trace(formatMappings(userType, methods));
}
// method 对应controller的方法； mapping 对应请求的url
methods.forEach((method, mapping) -> {
Method invocableMethod = AopUtils.selectInvocableMethod(method, userType);
// 注册handler 方法
registerHandlerMethod(handler, invocableMethod, mapping);
});
}
}
- 注册handler 方法
protected void registerHandlerMethod(Object handler, Method method, T mapping) {
this.mappingRegistry.register(mapping, handler, method);
}
看图就知道映射的url 和方法了
url 请求过来的时候就会走如下路径去获取 org.springframework.web.servlet.handler.AbstractHandlerMethodMapping#mappingRegistry 中的 handler方法
org.springframework.web.servlet.DispatcherServlet#doDispatch org.springframework.web.servlet.DispatcherServlet#getHandler org.springframework.web.servlet.handler.AbstractHandlerMapping#getHandler org.springframework.web.servlet.handler.AbstractHandlerMethodMapping#getHandlerInternal