Java 如何在方法中创建自动递增的id

我必须将-1替换为新购物者ID号的适当整数值

import java.util.Scanner;

public class MethodHolder {

    private static int nextShopperID = 100;
    private static int nextProductID = 100;

    protected static Shopper generateShopper(){

        Scanner scan = new Scanner(System.in);
        String name = null;
        double balance = 0.0;
        int productLimit = 0;

        System.out.println("Please enter the shoppers name: ");
        name = scan.next();
        System.out.println("Please enter the shoppers balance: ");
        balance = scan.nextDouble();
        System.out.println("Please enter the shoppers product limit: ");
        productLimit = scan.nextInt();


        // replace -1 with the appropriate increment expression
        return new Shopper(-1, name, balance, productLimit); 
    }

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尝试传入nextShopperID并递增它

return new Shopper(nextShopperID++, name, balance, productLimit);

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问题是什么？你知道什么是

if

语句吗？顺便问一下：下一个shopperid的目标是什么？这可能与你的问题有关吗？