java - 尝试使用类对象作为方法的参数时出现“变量可能未初始化”的错误，尝试使用 IF 来避免该问题（JAVA）

Question

我正在学习 JAVA，我正在为商店中的产品销售系统编写代码作为示例。所以我创建了产品、客户和销售类。

在我的菜单中，我检查是否有已注册的产品或客户，如果是，我调用具有这两个参数的销售方法。但是，NetBeans 会通知一个错误，即变量尚未初始化，即使之前未完成注册的逻辑也不开始销售。

我的基本代码：“变量产品可能尚未初始化”“变量客户可能尚未初始化”

//Main
//Reg a client and a product, then perform a sale.
package store;

import java.util.Random;
import java.util.Scanner;

public class Store {
static boolean flagProduct=false, flagCustomer=false;

   public static void main(String[] args) {
    menu();
   }
   
   public static void menu() {
   System.out.println("\n Choose option:\n"
   + "1 - Product Registration\n"
   + "2 - Customer Registration\n"
   + "3 - Sell\n"
   + "4 - End\n"
   );

   Scanner scanner = new Scanner(System.in);
   int select = scanner.nextInt();

   switch (select) {
       case 1:
       Product product = RegistProduct();
        System.out.print("\n Cod product : " + product.getCodProduct());
        System.out.print("\n Price product : " + product.getPriceProduct());
        System.out.print("\n Quantity product : " + product.getQuantProduct());
       menu();break;
       case 2:
       Customer customer = RegistCustomer();
       System.out.print("\n Cod Customer : " + customer.getCodCustomer());
       System.out.print("\n Customer name: " + customer.getName());
       menu();break;
       case 3:
           if(flagProduct == true && flagCustomer==true){ 
               Sale sale = sell(product, customer); // *****where the error happens*****
               System.out.print("\n Sale code : " + sale.getCodSale());
               System.out.print("\n Customer name: " + customer.getName());
               System.out.print("\n Cod product : " + product.getCodProduct()+ " -- Quantity:" + sale.getQuantSale()+ " -- Total:" + sale.getValueSale());
           } else if(flagProduct == true && flagCustomer==false){
               System.out.println("First register the customer ");
               menu();break;
           } else if(flagProduct == false && flagCustomer==true){
               System.out.println("First register the product");
               menu();break;
           } else
               System.out.println("First register the customer and product");
               menu();break;
       case 4:
       break;
       default:
       System.out.println("Error");
       menu();
   }
}

public static Product RegistProduct(){
   Product product = new Product();
   java.util.Scanner scanner = new Scanner(System.in);
   
   System.out.print("Product code:\n");
   product.setCodProduct(scanner.nextInt());
   
   System.out.print("Product price:\n");
   product.setPriceProduct(scanner.nextFloat());
   
   System.out.print("Product quantity:\n");
   product.setQuantProduct(scanner.nextInt());
   flagProduct = true;
   return product;  
}

public static Customer RegistCustomer(){
   Customer customer = new Customer();
   java.util.Scanner scanner = new Scanner(System.in);
   
   System.out.print("Customer name:\n");
   customer.setName(scanner.nextLine());
   
   System.out.print("Customer code:\n");
   customer.setCodCustomer(scanner.nextInt());
   
   flagCustomer=true;
   return customer;  
}


public static Sale Sell(Product product, Customer customer){
   java.util.Scanner scanner = new Scanner(System.in);
   
   Random num = new Random();
   int codSale = num.nextInt(9999);
   
   Sale sale = new Sale();
    
   sale.setCodSale(codSale);
   
     
   System.out.print("Customer code:");
   int codSaleCustomer = scanner.nextInt();
   
   while (codSaleCustomer != customer.getCodCustomer()){
       System.out.print("Non-existent code. Please enter a valid code:\n");
       codSaleCustomer = scanner.nextInt();
   }
   
     
   System.out.print("Product code:");
   int codSaleProduct = scanner.nextInt();
   
   while (codSaleProduct != product.getCodProduct()){
       System.out.print("Non-existent code. Please enter a valid code:\n");
       codSaleProduct = scanner.nextInt();
   }
   
   System.out.print("Quantity of products purchased:\n");
   sale.setQuantSale(scanner.nextInt());
   
   sale.setValueSale(sale.getQuantSale()*product.getPriceProduct());
   
   product.setQuantProduct(product.getQuantProduct() - sale.getQuantSale());
   System.out.print("Remaining quantity in stock: "+ product.getQuantProduct());
   return sale;
}
}

//Class Product
package store;

public class Product {

private int codProduct;
private float priceProduct;
private int quantProduct;

    public int getCodProduct() {
        return codProduct;
    }

    public void setCodProduct(int codProduct) {
        this.codProduct = codProduct;
    }

    public float getPriceProduct() {
        return priceProduct;
    }

    public void setPriceProduct(float priceProduct) {
        this.priceProduct = priceProduct;
    }

    public int getQuantProduct() {
        return quantProduct;
    }

    public void setQuantProduct(int quantProduct) {
        this.quantProduct = quantProduct;
    }

}

//Class customer
package store;

public class Customer {
    private int codCustomer;
    private String name;

    public int getCodCustomer() {
        return codCustomer;
    }

    public void setCodCustomer(int codCustomer) {
        this.codCustomer = codCustomer;
    }

    public String getName() {
        return name;
    }

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

       
}

//Class sale
package store;

public class Sale extends Product{ //I dnno if extends is necessary
    private int codSale;
    private int quantSale;
    private float valueSale;

    public int getCodSale() {
        return codSale;
    }

    public void setCodSale(int codSale) {
        this.codSale = codSale;
    }

    public int getQuantSale() {
        return quantSale;
    }

    public void setQuantSale(int quantSale) {
        this.quantSale = quantSale;
    }

    public float getValueSale() {
        return valueSale;
    }

    public void setValueSale(float valueSale) {
        this.valueSale = valueSale;
    }
   
}

标签： javaoop