在从JOptionPane下拉列表的输入上定价时遇到问题

Question

嘿，我一直在做这个任务，而且我已经撞墙了，不知道现在从哪里开始，但我需要付出代价来匹配每种方法中的每个重量类别。然后需要使用价格来生成增值税和总量。

   public class Delivery_Details 
       {
        private static String Timestamp;
        private static String tChoice;
        private static String wChoice;
        private static String cChoice;
        private static int price;
        private static int vat;
        public static int total;


       public static void main(String[] args) {

        townChoices();
        weightChoices();
        courierChoices();
        printDetails();

    }

    public static void printDetails()
            // printDetails() method will display Report
    {
        System.out.println("DELIVERY REPORT - " + "created on " + Timestamp);
        System.out.println("*************************************************");
        System.out.println("TOWN: " + tChoice);
        System.out.println("WEIGHT:" + wChoice);
        System.out.println("PRICE:" + " $`enter code here`" + price);
        System.out.println("VAT (14%):" + vat);
        System.out.println("TOTAL DUE:" + total);
        System.out.println("COURIER:" + cChoice);
        System.out.println("*************************************************");
    }

    private static void time() 
    {
     Timestamp = new SimpleDateFormat("yyyy-MM-dd      HH:mm:ss").format(Calendar.getInstance().getTime());

    }

    private static void townChoices() {
        String[] town = new String[3];
        town[0] = "CAPE TOWN";
        town[1] = "PRETORIA";
        town[2] = "DURBAN";

        Object selectedTown = JOptionPane.showInputDialog(null,"Choose town for parcel to be delivered to:", "Town options", JOptionPane.QUESTION_MESSAGE,null,town, "CAPE TOWN");
        tChoice = selectedTown.toString();
    }

    private static void weightChoices() 
    {
        String[] weight = new String[3];
        weight[0] = "0kg - 4kg";
        weight[1] = "5kg - 9kg";
        weight[2] = "Over 10kg";

        Object selectedTown = JOptionPane.showInputDialog(null,"Select the weight category of the parcel to be delivered to:"+ tChoice, "Town options", JOptionPane.QUESTION_MESSAGE,null,weight, "CAPE TOWN");
        wChoice = selectedTown.toString();

        price = Integer.parseInt(wChoice);
        if(wChoice.equals(weight[0]))
        {
            price = 300;
        }
        if(wChoice.equals(weight[1]))
        {
            price = 500;
        }
        if(wChoice.equals(weight[2]))
        {
            price = 700;
        }            
    }

    private static void courierChoices()
    {
        String[] courier = new String[3];
        courier[0] = "ABC Couriers";
        courier[1] = "Fast Track";
        courier[2] = "Rest Assured";

        Object selectedTown = JOptionPane.showInputDialog(null,"Select the courier company to deliver the parcel of weight" + wChoice + "to" + tChoice, "Town options", JOptionPane.QUESTION_MESSAGE,null,courier, "CAPE TOWN");
        cChoice = selectedTown.toString();
    }

    public static void vatAndtoal()
    {
        vat = price * 14/100;
        total = price + vat;
    }
} 

以下是我收到的例外情况：

Exception in thread "main" java.lang.NumberFormatException: For input string: "0kg - 4kg"
    at java.lang.NumberFormatException.forInputString(NumberFormatException.java:65)
    at java.lang.Integer.parseInt(Integer.java:580)
    at java.lang.Integer.parseInt(Integer.java:615)
    at delivery_details.Delivery_Details.weightChoices(Delivery_Details.java:77)
    at delivery_details.Delivery_Details.main(Delivery_Details.java:31)