Java实现枚举状态转换的方法详解

/**
 * 订单状态枚举
 */
public enum OrderStatusEnum {
    UNPAID(0, "待支付"),
    PAID(1, "已支付"),
    PACKAGED(2, "已打包"),
    SHIPPED(3, "已发货"),
    DELIVERED(4, "已送达"),
    COMPLETED(5, "已完成"),
    CANCELLED(10, "已取消"),
    REFUNDING(11, "退款中"),
    REFUNDED(12, "已退款");

    private final int code;
    private final String description;

    OrderStatusEnum(int code, String description) {
        this.code = code;
        this.description = description;
    }

    // 根据code获取枚举实例
    public static OrderStatusEnum fromCode(int code) {
        for (OrderStatusEnum status : values()) {
            if (status.code == code) {
                return status;
            }
        }
        throw new IllegalArgumentException("无效的订单状态码: " + code);
    }

    // 转换为物流状态
    public ShippingStatusEnum toShippingStatus() {
        switch (this) {
            case UNPAID:
            case PAID:
            case CANCELLED:
            case REFUNDING:
            case REFUNDED:
                return null; // 这些订单状态没有对应的物流状态
            case PACKAGED:
                return ShippingStatusEnum.PREPARING;
            case SHIPPED:
                return ShippingStatusEnum.IN_TRANSIT;
            case DELIVERED:
                return ShippingStatusEnum.DELIVERED;
            case COMPLETED:
                return ShippingStatusEnum.COMPLETED;
            default:
                throw new IllegalStateException("未知的订单状态: " + this);
        }
    }

    // getters
    public int getCode() { return code; }
    public String getDescription() { return description; }
}

/**
 * 物流状态枚举
 */
public enum ShippingStatusEnum {
    PREPARING(1, "准备中"),
    IN_TRANSIT(2, "运输中"),
    DELIVERED(3, "已送达"),
    COMPLETED(4, "已完成"),
    RETURNING(10, "退货中"),
    RETURNED(11, "已退货");

    private final int code;
    private final String description;

    ShippingStatusEnum(int code, String description) {
        this.code = code;
        this.description = description;
    }

    // 根据code获取枚举实例
    public static ShippingStatusEnum fromCode(int code) {
        for (ShippingStatusEnum status : values()) {
            if (status.code == code) {
                return status;
            }
        }
        throw new IllegalArgumentException("无效的物流状态码: " + code);
    }

    // 转换为订单状态
    public OrderStatusEnum toOrderStatus() {
        switch (this) {
            case PREPARING:
                return OrderStatusEnum.PACKAGED;
            case IN_TRANSIT:
                return OrderStatusEnum.SHIPPED;
            case DELIVERED:
                return OrderStatusEnum.DELIVERED;
            case COMPLETED:
                return OrderStatusEnum.COMPLETED;
            case RETURNING:
                return OrderStatusEnum.REFUNDING;
            case RETURNED:
                return OrderStatusEnum.REFUNDED;
            default:
                throw new IllegalStateException("未知的物流状态: " + this);
        }
    }

    // getters
    public int getCode() { return code; }
    public String getDescription() { return description; }
}

// 订单状态转物流状态
OrderStatusEnum orderStatus = OrderStatusEnum.SHIPPED;
ShippingStatusEnum shippingStatus = orderStatus.toShippingStatus();
System.out.println("订单状态: " + orderStatus.getDescription() 
    + " → 物流状态: " + (shippingStatus != null ? shippingStatus.getDescription() : "无"));

// 物流状态转订单状态
ShippingStatusEnum shippingStatus = ShippingStatusEnum.RETURNING;
OrderStatusEnum orderStatus = shippingStatus.toOrderStatus();
System.out.println("物流状态: " + shippingStatus.getDescription() 
    + " → 订单状态: " + orderStatus.getDescription());