static ResolvableType resolveDeclaredEventType(Class<?> listenerType) {
ResolvableType eventType = eventTypeCache.get(listenerType);
if (eventType == null) {
eventType = ResolvableType.forClass(listenerType).as(ApplicationListener.class).getGeneric();
eventTypeCache.put(listenerType, eventType);
}
return (eventType != ResolvableType.NONE ? eventType : null);
}
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ResolvableType.forClass(listenerType)这个时候创建的对象没有generic
as方法后有了generic
getGeneric直接从对象取的
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public ResolvableType as(Class<?> type) {
if (this == NONE) {
return NONE;
}
Class<?> resolved = resolve();
if (resolved == null || resolved == type) {
return this;
}
for (ResolvableType interfaceType : getInterfaces()) {
ResolvableType interfaceAsType = interfaceType.as(type);
if (interfaceAsType != NONE) {
return interfaceAsType;
}
}
return getSuperType().as(type);
}
这个递归里面getInterfaces最后得到的interfaceType 有 generic
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public ResolvableType[] getInterfaces() {
Class<?> resolved = resolve();
if (resolved == null) {
return EMPTY_TYPES_ARRAY;
}
ResolvableType[] interfaces = this.interfaces;
if (interfaces == null) {
Type[] genericIfcs = resolved.getGenericInterfaces();
interfaces = new ResolvableType[genericIfcs.length];
for (int i = 0; i < genericIfcs.length; i++) {
interfaces[i] = forType(genericIfcs[i], this);
}
this.interfaces = interfaces;
}
return interfaces;
}
这里面重点是 forType方法
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static ResolvableType forType(
@nullable Type type, @Nullable TypeProvider typeProvider, @Nullable VariableResolver variableResolver) {
if (type == null && typeProvider != null) {
type = SerializableTypeWrapper.forTypeProvider(typeProvider);
}
if (type == null) {
return NONE;
}
// 重点是这里
if (type instanceof Class) {
return new ResolvableType(type, typeProvider, variableResolver, (ResolvableType) null);
}
// Purge empty entries on access since we don't have a clean-up thread or the like.
cache.purgeUnreferencedEntries();
// Check the cache - we may have a ResolvableType which has been resolved before...
ResolvableType resultType = new ResolvableType(type, typeProvider, variableResolver);
ResolvableType cachedType = cache.get(resultType);
if (cachedType == null) {
cachedType = new ResolvableType(type, typeProvider, variableResolver, resultType.hash);
cache.put(cachedType, cachedType);
}
resultType.resolved = cachedType.resolved;
return resultType;
}
