Question

我有四节课。

Supplier，其中包含name，id。
SupplierDirectory Arraylist类型为Supplier。
Product，其中包含name。
ProductDirectory ArrayList类型Product。

Product.java

public class Product {
      //private int productId;
       private String productName;



       /* public int getProductId() {
        return productId;
    }

    public void setProductId(int productId) {
        this.productId = productId;
    }
     */
    public String getProductName() {
        return productName;
    }

        public void setProductName(String productName) {
           this.productName = productName;
      }

         /*     public int getPrice() {
           return price;
    }

    public void setPrice(int price) {
        this.price = price;
    }

    public boolean isAvailability() {
        return availability;
    }

    public void setAvailability(boolean availability) {
        this.availability = availability;
    }*/

    @Override
    public String toString()
    {
        return productName;
    }




}

ProductDirectory.java

    public class ProductDirectory {

    private ArrayList<Product> prodDir = new ArrayList<Product>();


     public ArrayList<Product> getProdDir() {
        return prodDir;
           }

    public void setProdDir(ArrayList<Product> prodDir) {
        this.prodDir = prodDir;
    }
    public Product addProduct()
    {
        Product prod = new Product();
        prodDir.add(prod);
        return prod;
    }

   }

Supplier.java

public class Supplier {

String supplierName;
private ProductDirectory proddirectory = new ProductDirectory();

public String getSupplierName() {
    return supplierName;
}

public void setSupplierName(String supplierName) {
    this.supplierName = supplierName;
}

public ProductDirectory getProddirectory() {
    return proddirectory;
}

public void setProddirectory(ProductDirectory proddirectory) {
    this.proddirectory = proddirectory;
}
}

SupplierDirectory.java

    public class SupplierDirectory {
    private ArrayList<Supplier> supplierDir = new ArrayList<Supplier>();

    public ArrayList<Supplier> getSupplierDir() {
        return supplierDir;
    }

    public void setSupplierDir(ArrayList<Supplier> supplierDir) {
        this.supplierDir = supplierDir;
    }

    public Supplier addsupplier()
    {
        Supplier sup = new Supplier();
        supplierDir.add(sup);
        return sup;
    }

    public void deleteSupplier(Supplier sup)
    {
        //Supplier sup = new Supplier();
        supplierDir.remove(sup);
    }
}

以下是我的主要方法。

public static void main (String[] args){

                    int i ,j;
                String supplierName;
                String productName;
                SupplierDirectory supDir = new SupplierDirectory();
                ProductDirectory prodDir = new ProductDirectory();
                Product p;
                Supplier Sup = new Supplier();
               Scanner user_input = new Scanner(System.in);             
               for (i = 0; i<=2; i++)
                {
                    System.out.println("Enter Supplier to add");
                    supplierName =  user_input.next();
                     supDir.addsupplier();
                    for (j=0;j<=3;j++)
                    {
                System.out.println("Enter Product to add"); 
                productName =  user_input.next();
                prodDir.addProduct();
                System.out.println("You have entered Product"+ prodDir); 
               System.out.println("Product List :"+ Sup.getProddirectory().getProdDir());
                  }              
                }

               // Scanner user_input = new Scanner(System.in);
                System.out.println("You have entered "+ userInput()); 

                System.out.println("You have entered "+ userInput());
                supDir.addsupplier();

                System.out.println("Suppliers  "+ supDir.getSupplierDir());

            }

    public static String userInput ()
    {
          String supplierName;
        Scanner user_input = new Scanner(System.in);
         System.out.println("Enter Supplier to add"); 
        supplierName =  user_input.next();
        return supplierName;
    }

           }

运行后，我得到以下结果：

输入供应商以添加

ABC

输入要添加的产品

戴尔

您已输入ProductBusiness.ProductDirectory@647e05

产品清单：[]

我该如何解决这个问题？

Answer 1

您应该更改这些行：

prodDir.addProduct();
System.out.println("You have entered Product"+ prodDir); 
System.out.println("Product List :"+ Sup.getProddirectory().getProdDir());

代替：

Product newProduct = new Product();
newProduct.setName(productName);
prodDir.getProdDir().put(newProduct);
System.out.println("You have entered Product"+ Arrays.toString(prodDir.getProdDir().toArray())); 
Sup.setProddirectory(prodDir);
System.out.println("Product List :"+ Arrays.toString(Sup.getProddirectory().getProdDir().toArray()));

还会向您的toString()类添加一个新的Product方法，如下所示：

@Override
public String toString() {
    return name;
}

来自productDirectory的{{1}}列表始终为空，因为您实例化了这样的新Supplier：

Supplier

但你从不打电话给Supplier Sup = new Supplier();

你应该添加一行

.setProddirectory()

行前

Sup.setProddirectory(prodDir);

System.out.println（）显示ProductDirectory @ 647e05和产品列表：[]

1 个答案: