java - 当子类对象存储在父类(super class)数组中时，如何调用子类方法？

{
    Ship ships = new Ship();
    CargoShip cargoShips = new CargoShip();
    CruiseShip cruiseShips = new CruiseShip();

    Ship[] allShips = {ships, cargoShips, cruiseShips};

    allShips[0].setShipName("Boom");
    allShips[0].setYearBuilt("1900");
    allShips[1].setShipName("Bang");
    allShips[1].setCargoCapaicty(200);
    allShips[2].setShipName("Bam");
    allShips[2].setMaxPassengers(500);


    for (int i = 0; i < allShips.length; i++)
    {
        System.out.println(allShips[i]);
    }
}

因此，Ship类是超类，而CargoShip和CruiseShip都扩展了Ship类。我已经将3个对象存储到Ship数组中。 setCargoCapacity和setMaxPassengers是仅出现在子类中的方法。由于某些原因，我无法访问它们。我不知道如何做到这一点，以便我也可以访问子类方法。

最佳答案

您可以在将对象存储在数组中之前对其进行初始化：

Ship ships = new Ship();
ships.setShipName("Boom");
ships.setYearBuilt("1900");

CargoShip cargoShips = new CargoShip();
cargoShips.setShipName("Bang");
cargoShips.setCargoCapaicty(200);

CruiseShip cruiseShips = new CruiseShip();
cruiseShips.setShipName("Bam");
cruiseShips.setMaxPassengers(500);

Ship[] allShips = {ships, cargoShips, cruiseShips};