从构造函数中的另一个类调用非静态方法

时间：2016-09-23 07:45:52

标签： java constructor static

我有一个汽车类，其构造函数如下所示：

public Cars(String carID, String plateNum, String position, Attendant assignedTo, long currTime) {
        this.carID = carID;
        this.plateNum = plateNum;
        this.position = position;
        this.assignedTo = assignedTo;
        this.currTime = currTime;
    }

当我从菜单中按下创建汽车时，构造函数在另一个类（main）中初始化。

构造函数的参数都是由car类中的方法创建/启动的。系统应该是提供信息的系统（如ID，位置和时间）。

问题是汽车对象尚未初始化，所以我无法使用这些方法。

但我真的需要汽车对象来包含其信息（如汽车ID：CR1）。

除时间外，所有信息都是字符串。

我该怎么做？

PS：我是编程新手。起初我使用静态但事实证明静态方法会给我的代码带来另一个更大的麻烦。

我发布了一些我的静态方法，每个人都告诉我删除静态。

public void addCar() {

    Cars car1 = new Cars(car1.getID(), car1.askCarID(), Cars.getPosition(), Attendant.askForAtt(), System.currentTimeMillis());
    myGarage.add(car1);
    if(!(car1.getAssignedTo()).equals(null)){
        car1.getAssignedTo().setAssign(car1);
        car1.getAssignedTo().setAvailable(false);
    }
}

当我想要创建一辆新车时，这就是所谓的。

我还把全车课程放在你需要的地方：

import java.util.ArrayList;
import java.util.Scanner;
import java.util.concurrent.TimeUnit;

import javax.swing.text.Position;

public class Cars {

    private String carID;
    private String plateNum;
    private String position;
    private Attendant assignedTo;
    private long currTime;
    static ArrayList<String> tempArray2 = new ArrayList<String>();

    public Cars(String carID, String plateNum, String position, Attendant assignedTo, long currTime) {
        this.carID = carID;
        this.plateNum = plateNum;
        this.position = position;
        this.assignedTo = assignedTo;
        this.currTime = currTime;
    }

    public void createCarsID() {

        for (int x = 0; x < Garage.getCarsCapacity(); x++) {
            String tempCarID = ("CR" + (x + 1));
            tempArray2.add(tempCarID);
        }
    }

    public String getID() {

        createCarsID();
        String tempID = null;
        String tempPos = null;
        for (int x = 0; x < Garage.getCarsCapacity(); x++) {
            if (tempArray2.get(x) != null) {
                tempID = tempArray2.get(x);
                tempPos = tempArray2.get(x);
                tempArray2.remove(tempArray2.get(x));
                getPos(tempPos);
                //tempArray2.get(x) = null;
                break;
            }
        }
        return tempID;
    }

    public static void getPos(String IdToPos) {
        String strPos = IdToPos.substring(2);
        int pos = Integer.parseInt(strPos);
        position = "GR" + pos;

    }

    public String getPlateNum() {
        return plateNum;
    }


    public static String getCarID() {
        return carID;
    }

    public static String getPosition() {
        return position;
    }

    public long getCurrTime() {
        return currTime;
    }

    public Attendant getAssignedTo() {
        return assignedTo;
    }

    public static String askCarID() {
        boolean valid = false;
        System.out.println("Please enter your car's plate number.");
        Scanner scanCarID = new Scanner(System.in);
        String scannedCarID = scanCarID.nextLine();
        while (!valid) {
            if (scannedCarID.matches("^[A-Za-z][A-Za-z] [0-9][0-9][0-9]$")) {
                valid = true;
                System.out.println(scannedCarID);
            } else {
                System.out.println("Please enter a valid plate number. Ex: AF 378");
                askCarID();
            }
        }
        return scannedCarID.toUpperCase();
    }

    public String convert(long miliSeconds) {
        int hrs = (int) TimeUnit.MILLISECONDS.toHours(miliSeconds) % 24;
        int min = (int) TimeUnit.MILLISECONDS.toMinutes(miliSeconds) % 60;
        int sec = (int) TimeUnit.MILLISECONDS.toSeconds(miliSeconds) % 60;
        return String.format("%02d:%02d:%02d", hrs, min, sec);
    }

        @Override
        public String toString() {
            return "Car:" + plateNum + " ID:" + carID + " Position:" + position + " Assigned to:" + assignedTo.getId() 
            + "(" + assignedTo.getName() + ")" + " Parked at:" + convert(currTime);
        }
    }

1 个答案:

答案 0 :(得分：1)

我附上了一个可以帮助您的代码：

首先，因为所有参数都可以是静态，然后移动到构造函数。

第二个我移动静态方法“createCarsID（）;”到静态初始化块，以避免不必要的调用。

该示例功能齐全。 

package test;
import java.util.ArrayList;
import java.util.Scanner;
import java.util.concurrent.TimeUnit;

import javax.swing.text.Position;

public class Cars {

private String carID;
private String plateNum;
private String position;
private Attendant assignedTo;
private long currTime;
static ArrayList<String> tempArray2 = new ArrayList<String>();

static{
    createCarsID();
}

public Cars() {
    this.carID = Cars.getID();
    this.plateNum = Cars.askCarID();
    this.position = Cars.generatePosition();
    this.assignedTo = Attendant.askForAtt();
    this.currTime = System.currentTimeMillis();
}

public static void createCarsID() {

    for (int x = 0; x < Garage.getCarsCapacity(); x++) {
        String tempCarID = ("CR" + (x + 1));
        tempArray2.add(tempCarID);
    }
}

public static String getID() {


    String tempID = null;
    String tempPos = null;
    for (int x = 0; x < Garage.getCarsCapacity(); x++) {
        if (tempArray2.get(x) != null) {
            tempID = tempArray2.get(x);
            tempPos = tempArray2.get(x);
            //tempArray2.remove(tempArray2.get(x));
            //getPos(tempPos);
            //tempArray2.get(x) = null;
            break;
        }
    }
    return tempID;
}
public static String generatePosition() {


    String tempID = null;
    String tempPos = null;
    for (int x = 0; x < Garage.getCarsCapacity(); x++) {
        if (tempArray2.get(x) != null) {
            tempID = tempArray2.get(x);
            tempPos = tempArray2.get(x);
            tempArray2.remove(tempArray2.get(x));
            return getPos(tempPos);
            //tempArray2.get(x) = null;

        }
    }
    return null;
}

public static String getPos(String IdToPos) {
    String strPos = IdToPos.substring(2);
    int pos = Integer.parseInt(strPos);
    return  "GR" + pos;

}

public String getPlateNum() {
    return plateNum;
}


public String getCarID() {
    return carID;
}

public String getPosition() {
    return position;
}

public long getCurrTime() {
    return currTime;
}

public Attendant getAssignedTo() {
    return assignedTo;
}

public static String askCarID() {
    boolean valid = false;
    System.out.println("Please enter your car's plate number.");
    Scanner scanCarID = new Scanner(System.in);
    String scannedCarID = scanCarID.nextLine();
    while (!valid) {
        if (scannedCarID.matches("^[A-Za-z][A-Za-z] [0-9][0-9][0-9]$")) {
            valid = true;
            System.out.println(scannedCarID);
        } else {
            System.out.println("Please enter a valid plate number. Ex: AF 378");
            askCarID();
        }
    }
    return scannedCarID.toUpperCase();
}

public String convert(long miliSeconds) {
    int hrs = (int) TimeUnit.MILLISECONDS.toHours(miliSeconds) % 24;
    int min = (int) TimeUnit.MILLISECONDS.toMinutes(miliSeconds) % 60;
    int sec = (int) TimeUnit.MILLISECONDS.toSeconds(miliSeconds) % 60;
    return String.format("%02d:%02d:%02d", hrs, min, sec);
}

    @Override
    public String toString() {
        return "Car:" + plateNum + " ID:" + carID + " Position:" + position + " Assigned to:" + assignedTo.getId() 
        + "(" + assignedTo.getName() + ")" + " Parked at:" + convert(currTime);
    }
}

最后为了调用这个函数：

package test;
public class main {
public static void main(String [] args){
    main test = new main();
    test.addCar();

}
public void addCar() {

    Cars car1 = new Cars();
    Garage myGarage = new Garage();
    myGarage.add(car1);
    if(!(car1.getAssignedTo()).equals(null)){
        car1.getAssignedTo().setAssign(car1);
        car1.getAssignedTo().setAvailable(false);
    }
}   
}
相关问题
最新问题