Java:优化代码

Question

我已经在这个电梯程序上工作了很长一段时间，最终完成了它，并使它工作，我为自己感到非常自豪，但我想看看如何优化我的代码，以便我可以学习未来。通过优化，我的意思是，让代码看起来更好，也许是通过使用更少的代码行。

static int floor = 0, choice1, person = 0;

public static void main(String args[])
{

    floor = ((int) (Math.random() * 10 + 1));

    System.out.println("The elevator is now on floor " +floor);
    System.out.print("Which floor are you at now (0-10) where 0 = basement: ");
    choice1 = Keyboard.readInt();

    if(floor == choice1)
    {
        System.out.println("Enter the elevator");
    }

    else if(floor > choice1)
    {
        ElevatorDown();
    }

    else if(floor < choice1)
    {
        ElevatorUp();
    }

    System.out.println("To which floor would you want to go (0-10) where 0 = basement");
    choice1 = Keyboard.readInt();

    if(floor > choice1)
    {
        ElevatorDown();
    }

    else if(floor < choice1)
    {
        ElevatorUp();
    }

}

public static void ElevatorUp()
{
    System.out.println("The elevator is on it's way up...");

    for (person = choice1; choice1>=floor; floor++)

    System.out.println(floor);

    System.out.println("The elevator has arrived");
}

public static void ElevatorDown()
{
    System.out.println("The elevator is on it's way down...");
    for (person = choice1; choice1<=floor; floor--)

    System.out.println(floor);

    System.out.println("The elevator has arrived");
}

Answer 1

试着让你的代码成为object-oriented.将电梯建模为对象。电梯能做什么？它可以上升和下降，所以你需要几个方法来做到这一点。电梯有哪些属性？它有一个当前的floor，这将是一个实例变量。您还需要一个构造函数来创建您的电梯。

确保使用有意义的变量名称，并适当地注释代码。

这里有一些代码可以帮助你：

public class Elevator {

    // the floor that the elevator is currently on
    private int currentFloor;

    /**
     * Creates an elevator at the specified floor.
     *
     * @param initialFloor the initial floor
     */
    public Elevator(int initialFloor) {
        this.currentFloor = initialFloor;
    }

    /**
     * @return the currentFloor
     */
    public int getCurrentFloor() {
        return currentFloor;
    }

    /**
     * Moves the elevator to the specified floor.
     *
     * @param floor the floor to go to.
     */
    public void goToFloor(int floor) {
        if (floor < currentFloor) {
            goDownToFloor(floor);
        } else if (floor > currentFloor) {
            goUpToFloor(floor);
        }
        System.out.println("The elevator has arrived");
    }

    /**
     * Moves the elevator up to the specified floor.
     *
     * @param floor the floor to go up to.
     */
    private void goUpToFloor(int floor) {
        System.out.println("The elevator is on its way up...");

        //TODO: put loop to go up to the floor here
    }

    /**
     * Moves the elevator down to the specified floor
     *
     * @param floor the floor to go down to.
     */
    private void goDownToFloor(int floor) {
        System.out.println("The elevator is on its way down...");

        //TODO: put loop to go down to the floor here        
    }
}

现在您需要一个main方法来创建电梯，读取用户输入并控制它。您可以为此创建一个新类，也可以将其添加到上面的Elevator类中。

public static void main(String[] args) throws Exception {

    //create an elevator at a random floor
    Elevator elevator = new Elevator(new Random().nextInt(11));

    int elevatorFloor = elevator.getCurrentFloor();
    System.out.println("The elevator is now on floor " + elevatorFloor);

    System.out.print("Which floor are you at now? (0-10) where 0 = basement: ");
    int personFloor = Keyboard.readInt();
    if(personFloor == elevatorFloor) {
        System.out.println("Enter the elevator");
    }
    else {
        elevator.goToFloor(personFloor);
    }

    System.out.println("To which floor would you want to go (0-10) where 0 = basement");
    int destinationFloor = Keyboard.readInt();
    elevator.goToFloor(destinationFloor);
}

将此方法与您当前的方法进行比较。它根据您可以对其执行的对象和操作对问题进行了更好的建模。代码重复的情况也更少。

Answer 2

• 使用集成开发环境(如NetBeans或Eclipse )，并让它格式化您的代码。
• 修复集成开发环境告诉您的任何警告。
• Add JavaDoc.
• Edit:使您的代码成为class.
• Edit:的一部分，遵循Java Naming Conventions

Answer 3

你可以在你的代码中做很多事情...除了Tichodroma提到的所有优点之外，你还需要在你的代码中进行异常处理。

我要消除的另一件事是doble代码部分，比如：

if(floor > choice1)
{
    ElevatorDown();
}

这些部分必须被提取出来，这样它才能只写一次。双代码段通常是code smell的指示器。

所有输出节(System.out.println...)可以在一种输出例程中提取，在我看来这样会更好。