如何使用Go语言开发点餐系统的配送费计算功能

package main

import (
    "encoding/JSON"
    "fmt"
    "io/ioutil"
    "net/Http"
)

const (
    AMapAPIKey = "your_amap_api_key"
)

type DistanceResponse struct {
    Status string `json:"status"`
    Info   string `json:"info"`
    Count  string `json:"count"`
    Route  struct {
        Orgin     string `json:"origin"`
        Destination   string `json:"destination"`
        Distance   float64 `json:"distance"`
        Duration   float64 `json:"duration"`
    } `json:"route"`
}

func GetDistance(origin, destination string) (float64, error) {
    url := fmt.Sprintf("https://restapi.amap.com/v3/distance?origins=%s&destination=%s&output=json&key=%s",
        origin, destination, AMapAPIKey)
    
    resp, err := http.Get(url)
    if err != nil {
        return 0, err
    }
    defer resp.Body.Close()

    body, err := ioutil.ReadAll(resp.Body)
    if err != nil {
        return 0, err
    }
    
    var distanceResponse DistanceResponse
    err = json.Unmarshal(body, &distanceResponse)
    if err != nil {
        return 0, err
    }

    return distanceResponse.Route.Distance, nil
}

func CalculateDeliveryFee(origin, destination string) (float64, error) {
    distance, err := GetDistance(origin, destination)
    if err != nil {
        return 0, err
    }

    deliveryFee := distance * 0.01 // 假设配送费为每公里0.01元

    return deliveryFee, nil
}

func main() {
    origin := "用户地址"
    destination := "商家地址"

    deliveryFee, err := CalculateDeliveryFee(origin, destination)
    if err != nil {
        fmt.Println("计算配送费失败：", err)
    }

    fmt.Println("配送费：", deliveryFee, "元")
}