java - switch case 中需要的常量表达式

Question

我已经为我的字符串初始化了常量表达式。这里似乎有什么问题？

我收到的错误是“需要常量表达式”。

下面是我的代码，

public class VatCalculator {

    private static int ONBOARD_SALE =1;
    private static int ONBOARD_SERVICE =2;
    private static int PREORDER_SALE =3;
    private static int PREORDER_SERVICE =4;

    private static final Map<String, Integer> serviceMap = new HashMap<String, Integer>();
    static {
        serviceMap.put("onboardSale", ONBOARD_SALE);
        serviceMap.put("onboardService", ONBOARD_SERVICE);
        serviceMap.put("preorderSale", PREORDER_SALE);
        serviceMap.put("preorderService", PREORDER_SERVICE);
    }



public static double calculate(String serviceGroup) {

int type = serviceMap.get(serviceGroup);

switch(type) {
//error at below line
case ONBOARD_SALE:
        //do something

default:break;
    }
}

Answer 1

使用这个:

private static final int ONBOARD_SALE = 1;