Java如何将多个类值添加到一个列表中，然后在重复提示的情况下解析该列表？

Question

我目前有5个类，它们接受几个条目并存储这些信息。这5个类是vanClass、truckClass等。在我的AutoPark类中，我创建了所有5个类的2个实例，并拥有10个变量，这些变量都包含我在声明它们时给出的信息。请看下面的内容以了解我所说的内容：

sedan1 = new sedan("Ford" , "Model-1" , "white" , 2015, 20000); // initialising sedan1 using sedan constructor
sedan2 = new sedan("Toyota" , "Model-2" , "gray" , 2010, 12000); // initialising sedan2 using sedan constructor

suv1 = new SUV("Ford" , "Model-1" , "white" , 2015, 20000, true); // initialising suv1 using SUV constructor
suv2 = new SUV("Toyota" , "Model-2" , "gray" , 2010, 12000, false); // initialising suv1 using SUV constructor
truck1 = new truckClass("Ford" , "Model-1" , 2015, 20000, true, "goods"); // initialising truck using truck constructor
truck2 = new truckClass("Toyota" , "Model-2" , 2010, 12000, false, "equipment"); // initialising truck using truck constructor

我需要能够搜索这5个类的10个实例中的所有字符串值。如何添加来自类的所有字符串值以生成以下内容：

下面是我的意思的一个例子：

Enter a string to search: FORD
There is a matching item available in our inventory
Enter a string to search: Sedan hatch back
No such item is available in our inventory.
Enter a string to search: honDA
There is a matching item available in our inventory
Enter a string to search: just a tire
No such item is available in our inventory.
Enter a string to search: quit

为了更好地理解，这里有完整的代码

import java.util.*;

class sedan {
    String make;
    String model;
    String color;
    int year;
    double price;
    boolean fourWD;
    boolean isheavyDuty;
    String carries;

    public sedan(String initMake, String initModel, String initColor, int initYear, double initPrice) {
        make = initMake;
        model = initModel;
        color = initColor;
        year = initYear;
        price = initPrice;
    }

    @Override
    public String toString() {
        String name = "Sedan";
        String main = (color + " " + make + " " + model + " " + name + " (" + year + ") costs $" + price);
        return main;
    }
}

class SUV {

    String make;
    String model;
    String color;
    int year;
    double price;
    boolean fourWD;
    String carries;

    public SUV(String initMake, String initModel, String initColor, int initYear, double initPrice, boolean initFourWD){
        make = initMake;
        model = initModel;
        color = initColor;
        year = initYear;
        price = initPrice;
        fourWD = initFourWD;
    }

    public String toString() {
        String name = "SUV";
        String main = new String();
        if (fourWD) {
            main = ("4WD " + color + " " + make + " " + model + " " + name + " (" + year + ") costs $" + price);
        }
        else {
            main = (color + " " + make + " " + model + " " + name + " (" + year + ") costs $" + price);
        }

        return main;
    }
}

class truckClass {

    String make;
    String model;
    String color;
    int year;
    double price;
    boolean fourWD;
    boolean isheavyDuty;
    String carries;

    public truckClass(String initMake, String initModel, int initYear, double initPrice, boolean initisheavyDuty, String initCarries) {
        make = initMake;
        model = initModel;
        year = initYear;
        price = initPrice;
        isheavyDuty = initisheavyDuty;
        carries = initCarries;

    }

    public String toString() {
        String name = "Truck";
        String main;
        if (isheavyDuty) {
            main = (make + " " + model + " heavy duty " + name + " (" + year + ") carries " + carries + " costs $" + price);

        }
        else {
            main = (make + " " + model + " " + name + " (" + year + ") carries " + carries + " costs $" + price);
        }

        return main;
    }
}
class vanClass {

    String make;
    String model;
    int year;
    double price;
    boolean isCovered;
    String carries;

    public vanClass(String initMake, String initModel, int initYear, double initPrice, boolean initisCovered, String initCarries){
        make = initMake;
        model = initModel;
        year = initYear;
        price = initPrice;
        isCovered = initisCovered;
        carries = initCarries;

    }

    public String toString() {
        String name;
        String main;
        if (isCovered){
            name = "covered Van";
            main = (make + " " + model + " " + name + " (" + year + ") carries " + carries + " costs $" + price);
        }
        else {
            name = "Van";
            main = (make + " " + model + " " + name + " (" + year + ") carries " + carries + " costs $" + price);
        }
        return main;
    }
}

class tireClass {

    int wheelDiameter;
    int sectionWidth;
    double price;
    boolean isPassengerTire;

    public tireClass(int initwheelDiameter, int initsectionWidth, double initPrice, boolean initisPassengerTire) {
        wheelDiameter = initwheelDiameter;
        sectionWidth = initsectionWidth;
        price = initPrice;
        isPassengerTire = initisPassengerTire;

    }

    public String toString() {
        String name;
        String main;
        if (isPassengerTire) {
            name = "Passenger tire ";
            main = (name + "with " + wheelDiameter + " in. wheel diameter " + sectionWidth +  "mm. section width, costs $" + price);
        }
        else {
            name = "Tire ";
            main = (name + "with " + wheelDiameter + " in. wheel diameter " + sectionWidth + "mm. section width, costs $" + price);
        }
        return main;

        }

    }

class AutoPark {
    String name;
    private sedan sedan1, sedan2;
    private SUV suv1, suv2;
    private truckClass truck1, truck2;
    private vanClass van1,van2;
    private tireClass tire1, tire2;
    private String item;
    private List myList;



    public AutoPark(String initName) {
        name = initName;
        sedan1 = new sedan("Ford" , "Model-1" , "white" , 2015, 20000); // initialising sedan1 using sedan constructor
        sedan2 = new sedan("Toyota" , "Model-2" , "gray" , 2010, 12000); // initialising sedan2 using sedan constructor

        suv1 = new SUV("Ford" , "Model-1" , "white" , 2015, 20000, true); // initialising suv1 using SUV constructor
        suv2 = new SUV("Toyota" , "Model-2" , "gray" , 2010, 12000, false); // initialising suv1 using SUV constructor

        truck1 = new truckClass("Ford" , "Model-1" , 2015, 20000, true, "goods"); // initialising truck using truck constructor
        truck2 = new truckClass("Toyota" , "Model-2" , 2010, 12000, false, "equipment"); // initialising truck using truck constructor

        van1 = new vanClass("Ford" , "Model-1" , 2015, 12000, true, "goods");
        van2 = new vanClass("Toyota" , "Model-2" , 2010, 45000, false, "equipment");

        tire1 = new tireClass(12,35,400,true);
        tire2 = new tireClass(8,45,350,false);

        List<String> myList = new ArrayList<String>();
        myList.add(sedan1.make);
        myList.add(sedan1.color);
        myList.add(sedan1.model);
        System.out.println(myList);


        }
    public void displayAllItems() {
        System.out.println("The " + name + " includes:");
        System.out.println(sedan1);
        System.out.println(sedan2);
        System.out.println(suv1);
        System.out.println(suv2);
        System.out.println(truck1);
        System.out.println(truck2);
        System.out.println(van1);
        System.out.println(van2);
        System.out.println(tire1);
        System.out.println(tire2);
    }

    public void searchItems(String initItem){
        //checks toString of any product in the parks inventory

        item = initItem;

        while (true) {
            if (myList.contains(item)) {
                System.out.println("TRUE");
            }
            else {
                System.out.println("False!");
            }
            break;
        }
    }
}

class AutoParkTesterProgram {
    public void main() {
        AutoPark a1;
        a1 = new AutoPark("Carleton Auto park");
        //a1.displayAllItems();

        //then loop repeatedly promt user to enter an item to search for
        //when type quit, process stops and program end
        //otherwise, searchitems of autopark used to search and result should be printed
        /*
Enter a string to search: FORD
There is a matching item available in our inventory
Enter a string to search: Sedan hatch back
No such item is available in our inventory.
Enter a string to search: honDA
There is a matching item available in our inventory
         */

    }
}


public class auto {
    public static void main(String args[]) {
        AutoPark a1;
        a1 = new AutoPark("Carleton Auto park");
        //a1.displayAllItems();
        a1.searchItems("ford");



    }
}

Answer 1

这类问题是使用类的绝佳机会。Java是一种面向对象的语言，您可以使用它来模拟类似的行为，这样您就不会在多个地方重复自己。

您的大多数类都是汽车，所以还有什么比创建Car类更好的方式来表示这一点呢？许多字段在car类之间共享，它们都可以移动到一个位置，如下所示：

public abstract class Car {
  public String make;
  public String model;
  public String color;
  public int year;
  public double price;
  public String carries;

  public Car(String make, String model, String color, int year, double price, String carries) {
    this.make = make;
    this.model = model;
    this.color = color;
    this.year = year;
    this.price = price;
    this.carries = carries;
  }
}

该类的abstract修饰符阻止您创建Car的新实例。那么为什么要为一个不能创建实例的类定义构造函数呢？这是因为你可以在任何子类的构造函数中调用它。

下面是一个如何对Sedan类建模的示例：

public class Sedan extends Car {
  public boolean fourWD;
  public boolean isHeavyDuty;

  public Sedan(String make, String model, String color, int year, double price, String carries, boolean fourWD, boolean isHeavyDuty) {
    super(make, model, color, year, price, carries);
    this.fourWD = fourWD;
    this.isHeavyDuty = isHeavyDuty;
  }

  @Override
  public String toString() {
    String name = "Sedan";
    String main = (color + " " + make + " " + model + " " + name + " (" + year + ") costs $" + price);
    return main;
  }
}

extends Car允许您在Car类中定义的逻辑之上进行构建。在这里，Sedan构造函数可以通过使用super并传递必要的参数来调用Car构造函数。然后，您可以像以前一样覆盖toString方法。

您可以为SUV、卡车和面包车创建类似的类，这样您就不需要重复公共字段，并且可以专注于区分每种类型的车辆。

那么，所有这些如何帮助您解决搜索字符串的初始问题呢？在您的AutoPark类中，您可以使用List<Car>来跟踪公园中的所有车辆。由于这些对象中的每一个都将是Car类型，因此您将能够对所有这些对象做出某些假设，例如，每个对象都将具有一个make字段。您还可以将Car类的任何实例添加到此List中，而不必创建新变量。

现在，当您在searchItems中搜索字符串时，可以遍历所有汽车，查看其中是否有字段包含要搜索的字符串。如果您使用的是for-each循环，它可能如下所示：

for (Car car: cars) {
  if (car.make.contains(initItem) || car.model.contains(initItem)) {
    System.out.println("TRUE");
    break;
  } else {
    System.out.println("False!");
  }
}