构建3个电梯的电梯组,楼层在10层以上,模拟其运行。要求电梯组并联运行,即按下按钮后,自动根据楼层和移动方向调度最优的电梯(假设每台电梯上下一层都是1s,开关门时间为1s)用Java写。

好的，我可以为您解答这个问题。以下是一个简单的电梯调度系统的Java代码，其中包含了三台电梯的模拟运行。

import java.util.*;

enum Direction {
    UP, DOWN, HOLD
}

class Elevator {
    private int id;
    private int currentFloor;
    private Direction direction;
    private Set<Integer> destinations;

    public Elevator(int id, int currentFloor) {
        this.id = id;
        this.currentFloor = currentFloor;
        this.direction = Direction.HOLD;
        this.destinations = new HashSet<>();
    }

    public int getId() {
        return id;
    }

    public int getCurrentFloor() {
        return currentFloor;
    }

    public Direction getDirection() {
        return direction;
    }

    public Set<Integer> getDestinations() {
        return destinations;
    }

    public void addDestination(int floor) {
        destinations.add(floor);
    }

    public void moveUp() {
        currentFloor++;
    }

    public void moveDown() {
        currentFloor--;
    }

    public void hold() {
        direction = Direction.HOLD;
    }

    public void setDirection(Direction direction) {
        this.direction = direction;
    }

    public boolean shouldStop(int floor) {
        if (destinations.contains(floor)) {
            destinations.remove(floor);
            return true;
        }
        if (direction == Direction.UP && floor > currentFloor) {
            return false;
        }
        if (direction == Direction.DOWN && floor < currentFloor) {
            return false;
        }
        return destinations.isEmpty();
    }
}

class ElevatorSystem {
    private List<Elevator> elevators;
    private int numFloors;

    public ElevatorSystem(int numElevators, int numFloors) {
        this.numFloors = numFloors;
        this.elevators = new ArrayList<>();
        for (int i = 0; i < numElevators; i++) {
            elevators.add(new Elevator(i + 1, 1));
        }
    }

    public List<Elevator> getElevators() {
        return elevators;
    }

    public int getNumFloors() {
        return numFloors;
    }

    public Elevator requestElevator(int floor, Direction direction) {
        Elevator nearest = null;
        int minDistance = Integer.MAX_VALUE;
        for (Elevator elevator : elevators) {
            if (elevator.getDirection() == Direction.HOLD) {
                int distance = Math.abs(elevator.getCurrentFloor() - floor);
                if (distance < minDistance) {
                    minDistance = distance;
                    nearest = elevator;
                }
            } else if (elevator.getDirection() == direction) {
                if (direction == Direction.UP && elevator.getCurrentFloor() < floor) {
                    int distance = Math.abs(elevator.getCurrentFloor() - floor);
                    if (distance < minDistance) {
                        minDistance = distance;
                        nearest = elevator;
                    }
                } else if (direction == Direction.DOWN && elevator.getCurrentFloor() > floor) {
                    int distance = Math.abs(elevator.getCurrentFloor() - floor);
                    if (distance < minDistance) {
                        minDistance = distance;
                        nearest = elevator;
                    }
                }
            }
        }
        if (nearest != null) {
            nearest.addDestination(floor);
            if (nearest.getDirection() == Direction.HOLD) {
                if (nearest.getCurrentFloor() < floor) {
                    nearest.setDirection(Direction.UP);
                } else if (nearest.getCurrentFloor() > floor) {
                    nearest.setDirection(Direction.DOWN);
                }
            }
        }
        return nearest;
    }

    public void step() {
        for (Elevator elevator : elevators) {
            if (elevator.getDirection() == Direction.UP) {
                elevator.moveUp();
                if (elevator.shouldStop(elevator.getCurrentFloor())) {
                    elevator.hold();
                } else if (elevator.getCurrentFloor() == numFloors) {
                    elevator.setDirection(Direction.DOWN);
                }
            } else if (elevator.getDirection() == Direction.DOWN) {
                elevator.moveDown();
                if (elevator.shouldStop(elevator.getCurrentFloor())) {
                    elevator.hold();
                } else if (elevator.getCurrentFloor() == 1) {
                    elevator.setDirection(Direction.UP);
                }
            } else if (!elevator.getDestinations().isEmpty()) {
                int destination = elevator.getDestinations().iterator().next();
                if (destination > elevator.getCurrentFloor()) {
                    elevator.setDirection(Direction.UP);
                } else if (destination < elevator.getCurrentFloor()) {
                    elevator.setDirection(Direction.DOWN);
                }
            }
        }
    }
}

public class Main {
    public static void main(String[] args) {
        ElevatorSystem system = new ElevatorSystem(3, 20);
        Scanner scanner = new Scanner(System.in);
        while (true) {
            System.out.print("Enter floor number (1-20): ");
            int floor = scanner.nextInt();
            System.out.print("Enter direction (UP or DOWN): ");
            Direction direction = Direction.valueOf(scanner.next().toUpperCase());
            Elevator elevator = system.requestElevator(floor, direction);
            System.out.println("Elevator " + elevator.getId() + " is on its way to floor " + floor);
            while (!elevator.getDestinations().isEmpty()) {
                system.step();
            }
            System.out.println("Elevator " + elevator.getId() + " has arrived at floor " + floor);
        }
    }
}

以上代码使用了枚举类型来表示电梯的运行方向和是否停留。系统通过循环调用 `step()` 方法来模拟电梯的运行，直到所有电梯都没有任务为止。您可以根据需要添加更多的功能，例如等待时间和错误检查。