1 楼的这个 ResolvableType ，其实也是 Spring 基于 java 的反射实现的，
```
public ResolvableType[] getGenerics() {
if (this == NONE) {
return EMPTY_TYPES_ARRAY;
}
if (this.generics == null) {
if (this.type instanceof Class) {
Class<?> typeClass = (Class<?>) this.type;
this.generics = forTypes(SerializableTypeWrapper.forTypeParameters(typeClass), this.variableResolver);
}
else if (this.type instanceof ParameterizedType) {
Type[] actualTypeArguments = ((ParameterizedType) this.type).getActualTypeArguments();
ResolvableType[] generics = new ResolvableType[actualTypeArguments.length];
for (int i = 0; i < actualTypeArguments.length; i++) {
generics[i] = forType(actualTypeArguments[i], this.variableResolver);
}
this.generics = generics;
}
else {
this.generics = resolveType().getGenerics();
}
}
return this.generics;
}