golang讀取json格式的天氣預報

這是一個建立於 的文章，其中的資訊可能已經有所發展或是發生改變。

使用天氣預報的介面：http://weather.china.xappengine.com/api?city=南寧 （找了好久才找到一個支援拼音的，不過好像小地方是沒資料的）

訪問得到json格式壓縮的資料，格式化後

{    "pub": "2013-06-29 22:59",    "name": "南寧",    "wind": {        "chill": 81,        "direction": 140,        "speed": 7    },    "astronomy": {        "sunrise": "6:05",        "sunset": "19:34"    },    "atmosphere": {        "humidity": 89,        "visibility": 6.21,        "pressure": 29.71,        "rising": 1    },    "forecasts": [        {            "date": "2013-06-29",            "day": 6,            "code": 29,            "text": "局部多雲",            "low": 26,            "high": 32,            "image_large": "http://weather.china.xappengine.com/static/w/img/d29.png",            "image_small": "http://weather.china.xappengine.com/static/w/img/s29.png"        },        {            "date": "2013-06-30",            "day": 0,            "code": 30,            "text": "局部多雲",            "low": 25,            "high": 33,            "image_large": "http://weather.china.xappengine.com/static/w/img/d30.png",            "image_small": "http://weather.china.xappengine.com/static/w/img/s30.png"        },        {            "date": "2013-07-01",            "day": 1,            "code": 37,            "text": "局部雷雨",            "low": 24,            "high": 32,            "image_large": "http://weather.china.xappengine.com/static/w/img/d37.png",            "image_small": "http://weather.china.xappengine.com/static/w/img/s37.png"        },        {            "date": "2013-07-02",            "day": 2,            "code": 38,            "text": "零星雷雨",            "low": 25,            "high": 32,            "image_large": "http://weather.china.xappengine.com/static/w/img/d38.png",            "image_small": "http://weather.china.xappengine.com/static/w/img/s38.png"        },        {            "date": "2013-07-03",            "day": 3,            "code": 38,            "text": "零星雷雨",            "low": 25,            "high": 32,            "image_large": "http://weather.china.xappengine.com/static/w/img/d38.png",            "image_small": "http://weather.china.xappengine.com/static/w/img/s38.png"        }    ]}

GO語言內建的encoding/json標準庫，Json.Unmarshal() 可以解析json資料

約定：json中的布爾值會解析為布爾值，數字（整數，浮點型）解析為float64，string解析為string，數組解析為介面數組，空值解析為nil。 這些欄位在型別宣告中必須都是以大寫字母開頭、可被匯出的欄位。

Json.Unmarshal()函數會根據一個約定的順序尋找目標結構中的欄位，如果找到一個則進行匹配。當JSON資料中的資料結構和GO中的目標類型不符時，json.Unmarshal（）函數在解碼過程中會丟棄該欄位。

 Json.Unmarshal()函數也支援讀取未知的結構的json資料，允許使用map[string]interface{}和[]interface{}類型的值來分別存放未知結構的JSON對象或數組。

package mainimport (    "encoding/json""io/ioutil""net/http""fmt")//對應json天氣資料來源的結構，頭字母大寫type WeatherInfoJson struct {Pub        stringName       stringWind       WindObjectAstronomy  AstronomyObjectAtmosphere AtmosphereObjectForecasts  []ForecastsObject}type WindObject struct {Chill     float64Direction float64Speed     float64}type AstronomyObject struct {Sunrise stringSunset  string}type AtmosphereObject struct {Humidity   float64Visibility float64Pressure   float64Rising     float64}type ForecastsObject struct {Date        stringDay         float64Code        float64Text        stringLow         float64High        float64Image_large stringImage_small string}func GetWeather(city string) {str:="http://weather.china.xappengine.com/api?city="+cityresp, err := http.Get(str)  //使用get方法訪問if err != nil {return}defer resp.Body.Close()input, err1 := ioutil.ReadAll(resp.Body)    //讀取流資料if err1 != nil {return}var jsonWeather WeatherInfoJsonerr2:=json.Unmarshal(input, &jsonWeather)   //解析json資料if err2 != nil {return}if len(jsonWeather.Name)!=0 {   //判斷有無解析資料    for i := 0; i < 3; i++ {        fmt.Printf("-->地區:%s 時間:%s 溫度:%d-%d 天氣:%s 發布時間:%s\n", jsonWeather.Name,jsonWeather.Forecasts[i].Date,int(jsonWeather.Forecasts[i].Low),int(jsonWeather.Forecasts[i].High),jsonWeather.Forecasts[i].Text,jsonWeather.Pub)    }    }}func main(){    GetWeather("深圳")    GetWeather("nanning")}

運行結果如下