问题
I have class - AbstractOrder - it have basic realization and fields. And also i have three another which extends AbstractOrder - EmployeeOrder, StudentOrder, PostgraduateOrder, but have additional field - id. I would like to create a single validation class for all 3 entities. Here is my code. So, my question is "how to create an object of instance of nessasary class and cast object to it using Reflection api". My entities doesn't have a constructors. I try to something like that:
@Service
public class TripOrderValidator implements Validator {
@Autowired
private TripOrderService tripOrderService;
Class <?> typeOfOrder;
@Override
public boolean supports(Class<?> aClass) {
if (AbstractTripOrder.class.isAssignableFrom(aClass)) {
typeOfOrder = aClass;
return true;
} else {
return false;
}
}
@Override
public void validate(Object o, Errors errors) {
Class<? extends AbstractTripOrder> tripOrder = (Class<? extends AbstractTripOrder>) typeOfOrder.cast(o);
//can't execute the method
//tripOrder.getNumber();
}
}
But i can't call the methods of the class. I want to use it like that. For example. In method support i have class EmployeeOrder. Then in validate method i create object and cast parameter o to that classType:
EmployeeOrder order = (EmployeeOrder) o;
来源：https://stackoverflow.com/questions/60898252/how-to-cast-instance-by-classname-in-springs-validator-interface-realization