如何将 ArrayList 中的 return 项存储在不同的文件中？

Question

所以我目前拥有的代码可以 return 对数组中对象的引用，但不会显示其中的数据。代码的第一位是用户输入数据的主文件，但对象引用仅 returns 用户输入的最后一个对象，我需要的是要搜索的数组以及是否找到它该项目显示与该对象一起存储的数据。

第一个文件。

import java.util.Scanner;
import java.util.*;
import java.util.ArrayList;

public class Inv
{


    public static void main(String args[])
    {

        Scanner console = new Scanner(System.in);

        String str;
        char c;
        int n=0;


        //Product product  = new Product();


        System.out.println("        INVENTORY MANAGEMENT SYSTEM");
        System.out.println("===============================================");
        System.out.println("1. ADD PRODUCT DATA");
        System.out.println("2. VIEW PRODUCT DATA");
        System.out.println("3. VIEW REPRLENISHMENT STRATEGY");
        System.out.println("===============================================");
        System.out.println("4. EXIT PROGRAM");

        while(n!=4)
        {
            System.out.print("\n Please enter option 1-4 to continue...: ");
            n = Integer.parseInt(System.console().readLine());

            if (n>4||n<1)
            {
                System.out.print("Invalid input, please try again...");
                continue;
            }
            if (n==1)
            {
                str="y";
                while(str.equals("y")||str.equals("Y"))
                {

                    Inv.addItem();
                    System.out.print("Would you like to enter another product ? (Y or N) : ");
                    str = console.next();
                }   
                continue;
            }
            if (n==2)
            {
                str="y";
                while(str.equals("y")||str.equals("Y"))
                {
                    Inv.prodData();
                    System.out.println("\n***************************************************\n");
                    System.out.print("Stay viewing this page? (Y or N) ");
                    str = console.next();

                }
                continue;
            }
            else

            if (n==3)
            {
                System.out.print("View Replenishment Strategy.");
                continue;
            }
        }
        System.out.print("\nThank you for using this inventory management software.\n");
        System.out.print("Developed by Xavier Edwards");
        System.out.println("\n***************************************************\n");

    }

    public static Product product;
    public static Store store;
    public static void addItem ()
    {
        Scanner console = new Scanner(System.in);
        product = new Product();
        store = new Store();

        String desc, id, str="";
        double price = 0, sUpPrice = 0, unitCost = 0, inventoryCost = 0;
        int stock = 0, demand = 0;

        //if (product == null) //If product 1 is empty
        //{
            System.out.print("Please enter product description between 3 to 10 characters...: ");
            desc = console.next();
            desc = desc.toLowerCase();
            product.setName(desc);

            if ((desc.length() < 3 || desc.length() > 10))
            {
                System.out.println("\nThis Input is incorrect. Please make description between 3 to 10 characters.\n");
                System.out.println("Try again with different input. ");
                System.out.println("\n*****************************************\n");
                Inv.addItem();
            }

            System.out.print("Please enter price in $ : ");
            price = console.nextDouble();
            product.setPrice(price);

            if (price < 0)
            {
                System.out.println("\nThis Input is incorrect. Please make sure attributes are positve numbers\n");
                System.out.println("Because of incorrect input, program will restart. ");
                System.out.println("\n*****************************************\n");
                Inv.addItem();
            }

            System.out.print("Please enter set up price. $ : ");
            sUpPrice = console.nextDouble();
            product.setsUpPrice(sUpPrice);

            if (sUpPrice < 0)
            {
                System.out.println("\nThis Input is incorrect. Please make sure attributes are positve numbers\n");
                System.out.println("Because of incorrect input, program will restart. ");
                System.out.println("\n*****************************************\n");
                Inv.addItem();
            }

            System.out.print("Please enter unit- cost. $ : ");
            unitCost = console.nextDouble();
            product.setunitCost(unitCost);

            if (unitCost < 0)
            {
                System.out.println("\nThis Input is incorrect. Please make sure attributes are positve numbers\n");
                System.out.println("Because of incorrect input, program will restart. ");
                System.out.println("\n*****************************************\n");
                Inv.addItem();
            }

            System.out.print("Please enter the inventory cost. $ : ");
            inventoryCost = console.nextDouble();
            product.setinvCost(inventoryCost);

            if (inventoryCost < 0)
            {
                System.out.println("\nThis Input is incorrect. Please make sure attributes are positve numbers\n");
                System.out.println("Because of incorrect input, program will restart. ");
                System.out.println("\n*****************************************\n");
                Inv.addItem();
            }

            System.out.print("Please enter the amount in stock : ");
            stock = console.nextInt();
            product.setstock(stock);

            if (stock < 0)
            {
                System.out.println("\nThis Input is incorrect. Please make sure attributes are positve numbers\n");
                System.out.println("Because of incorrect input, program will restart. ");
                System.out.println("\n*****************************************\n");
                Inv.addItem();
            }

            System.out.print("Please enter the demand of the product : ");
            demand = console.nextInt();
            product.setdRate(demand);

            if (demand < 0)
            {
                System.out.println("\nThis Input is incorrect. Please make sure attributes are positve numbers\n");
                System.out.println("Because of incorrect input, program will restart. ");
                System.out.println("\n*****************************************\n");
                Inv.addItem();
            }

            System.out.println("\n*****************************************\n");
            System.out.print(desc +" Product was added successfully ");
            System.out.println("\n*****************************************\n");
            store.add(product);

        //}
    }

    public static void prodData()
    {
        Scanner console = new Scanner(System.in);
        String pOption, str;

        System.out.print("\nEnter product description to view the data...\n");
        pOption = console.next();

        if (product == null)
        {
            System.out.println("\nThere is no information on this product.\n");

            System.out.println("\nWould you like to try again? (Y or N) \n");
            str = console.next();
            Inv.prodData();
        }

        System.out.println("The information for the product is..... ");
        System.out.println("\n*****************************************\n");
        System.out.println(store.ProductList.get(0));
        if (product.equals(store.ProductList.get(0)))
        {
            System.out.println("Product description : "+product.getName());
            System.out.println("Price : $ "+product.getPrice());
            System.out.println("Set-up Price : $ "+product.getsUpPrice());
            System.out.println("Unit Cost : $ "+product.getunitCost());
            System.out.println("Inventory Cost : $ "+product.getinvCost());
            System.out.println("Amount of Stock : "+product.getstock());
            System.out.println("Amount of Stock : "+product.getdRate());
        }*/
    }

}

创建数组列表和存储对象的第二个文件。

import java.util.*;
import java.util.ArrayList;

public class Store{
    public ArrayList <Product> ProductList = new ArrayList<Product> ();

    public Store()
    {
        //ArrayList = "";

    }

    public void add(Product product)
    {           
        ProductList.add(product);
    }

    public Product getProduct(String prodName) {
        for (int i = 0; i < ProductList.size(); i++) {
            if (ProductList.get(i).getName().equals(prodName)) {
                return ProductList.get(i);
            }
        }
        return null;
 }

}

用于存储特定用户条目的代码

public class Product
{
    public String name;
    public double price, sUpPrice, unitCost, invCost;
    public int stock, demand;


    public Product()
    {
        name = "";
        price = 0;
        sUpPrice = 0;
        unitCost = 0;
        invCost = 0;
        stock = 0;
        demand = 0;

    }

        public void setName(String name) {
            this.name = name;
        }
        public String getName() {
            return this.name;
        }

        public void setPrice(double price) {
            this.price = price;
        }
        public double getPrice() {
            return this.price;
        }   
        public void setsUpPrice(double sUpPrice) {
            this.sUpPrice = sUpPrice;
        }
        public double getsUpPrice() {
            return this.sUpPrice;
        }   
        public void setunitCost(double unitCost) {
            this.unitCost = unitCost;
        }
        public double getunitCost() {
            return this.unitCost;
        }   
        public void setinvCost(double invCost) {
            this.invCost = invCost;
        }
        public double getinvCost() {
            return this.invCost;
        }
        public void setstock(int stock) {
            this.stock = stock;
        }
        public int getstock() {
            return this.stock;
        }
        public void setdRate(int demand) {
            this.demand = demand;
        }
        public int getdRate() {
            return this.demand;
        }

}

这就是另一个名为 product.java

的文件中的代码

Answer 1

如果我没理解错的话，你是想让用户输入产品名称，然后显示产品的所有数据。

您可能应该使用 getProduct 方法。

product = store.getProduct(pOption);
if (product != null){
    System.out.println("Product description : "+product.getName());
    System.out.println("Price : $ "+product.getPrice());
    System.out.println("Set-up Price : $ "+product.getsUpPrice());
    System.out.println("Unit Cost : $ "+product.getunitCost());
    System.out.println("Inventory Cost : $ "+product.getinvCost());
    System.out.println("Amount of Stock : "+product.getstock());
    System.out.println("Amount of Stock : "+product.getdRate());
}else{
    System.out.println("\nThere is no information on this product.\n");
    System.out.println("\nWould you like to try again? (Y or N) \n");
    str = console.next();
    Inv.prodData();
}

Answer 2

public class Inv {


    //read data from any way you prefer and call the methods on store class
    //since the class methods and the productlist are marked as static
    //every class on your project is accessing and changing the same productlist

    Store.add("your product object");
    Store.getProduct("your name");


}


class Store{
    public static ArrayList <product> ProductList = new ArrayList<product> (); 

    public static void add(product product){
    ProductList.add(product);
    }

    public static product getProduct(String prodName) {
        for (int i = 0; i < ProductList.size(); i++) {
            if (ProductList.get(i).getName().equals(prodName)) {
                return ProductList.get(i);
            }
        }
        return null;
    }

       //implement new static methods to remove products from productlist
    public static removeProduct(String name){
       //code to remove product
    }


    public static removeAll(){
    //code to clear the productlist
    }


}

您需要在代码中遵循此方法，注释中提供了说明

如何将 ArrayList 中的 return 项存储在不同的文件中？

How do you return items from ArrayList that is stored in a different file?

java

file

arraylist

return-value