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向列表中添加项目

list java

matteo panaro · 技术社区 · 1 年前

我需要向列表中添加一个类项,必须通过键盘输入添加。我无法添加其属性

产品类别

import java.util.*;

public class Product {
    public double price;
    public int quantity;
    private String id_product;
    
    public Prodotto (double price, int quantity, String id_product) {
        this.price = price;
        this.quantity = quantity;
        this.id_product = id_product;
    }
    public double getPrice() {
        return price;
    }
    public int getQuantity() {
        return quantity;
    }
    
    public String getId_product() {
        return id_product;
    }
    


}

产品列表类

import java.util.*;

public class ProductList {
    List <Product> productList;
    
    public ProductList() {
        productList = new LinkedList<Product>();
    }
    
    public void addProduct(Product p) {
        productList.add(p);
    }
    
    public int getSize() {
        return productList.size();
    }
    
    public Product getProduct(int i) {
        return productList.get(i);
    }

    public void add(String next) {
        
    }
    
    
}

主类仍在开发中,我删除了一些额外的操作,以便让你更清楚,但第一个操作给我带来了麻烦

import java.util.*;

public class WarehouseManagement {

    public static void main(String[] args) {
        // TODO Auto-generated method stub
    
    ProductList el_product = new ProductList();
    
    Scanner sc = new Scanner(System.in);
    
    boolean stop = false;
    while(!stop) {
        System.out.println("Available Operations:");
        System.out.println("1 - Add Product");
        
        System.out.print("Insert your choice: ");
        int choice = sc.nextInt();
        
        Product [] products
        
        
        switch (choice) {
            case 1:
                System.out.print("Insert product: ");
                el_product.add(sc.next());
                
                break;
        }
    
        
        }
    }

    }

有了这个,我可以添加一个产品,但不能添加他的价格、数量和Id,我该怎么做?

2 回复 | 直到 1 年前

ControlAltDel 1 年前

我建议您在Product中添加一个静态方法,通过扫描仪获取输入并返回Product

public static Product createProduct (Scanner s) {
    double price, 
    int quantity;
    String id_product;
    System.out.println("Enter the price");
    price = s.nextDouble();
    System.out.println("Enter the quantity");
    quantity = s.nextInt();
    System.out.println("Enter the product ID");    
    id_product = s.next();
    return new Product(price, quantity, id_product);
}

您可能希望进一步细分,以便最初只创建产品id,然后可以创建添加数量或设置价格的方法。

Marce Puente 1 年前

也许这样的东西会帮助你:

public static void main( String[] args ) {
   ProductList el_product = new ProductList();
   Scanner sc = new Scanner( System.in );
   double price = 0d;
   int quantity = 0;
   String id_product = "";

   // we create the string with all messages
   String msgs = "Enter the number of products//product//Enter the price//Enter the quantity//Enter the product ID";

   // we create the array of messages
   String messages[] = msgs.split( "//" );
   
   // we ask the user how many products he/she wants to create
   // and instantiate "numberOfProduct" with the obtained value
   System.out.println( messages[ 0 ] );
   int numberOfProduct = Integer.parseInt( sc.nextLine() );

   for( int k = 0; k < numberOfProduct; k ++ ) {

      // show the second message
      System.out.println( "create the " + ( k + 1 ) + "Â° " + messages[ 1 ] );

      // i = 2 to start displaying from the third message
      for( int i = 2; i < messages.length; i ++ ) {
         while( true ) {

            // show the message for each item
            System.out.println( messages[ i ] );
            try {
               String data = sc.nextLine();
               if( i == 0 ) {
                  price = Double.parseDouble( data );
                  break;
               }
               else if( i == 1 ) {
                  quantity = Integer.parseInt( data );
                  break;
               }
               else {
                  id_product = data;
                  break;
               }
            }
            catch( Exception e ) { }
         }
      }
      // add to the list the new "Product"
      el_product.add( new Product( price, quantity, id_product ));
   }
}