GO中Json的解析

一个json字串，想要拿到其中的数据，就需要解析出来

一、适用于json数据的结构已知的情况下

使用json.Unmarshal将json数据解析到结构体中

根据json字串数据的格式定义struct，用来保存解码后的值。这里首先定义了一个与要解析的数据结构一样的结构体，然后通过json.Unmarshal进行解码，如果json数据很复杂，自定义的struct就跟着复杂。

package mainimport ("encoding/json""fmt"
)var jsonstr = `{"province":{"value":"110000","label":"北京市"},"city":{"value":"110100","label":"北京城区"},"district":{"value":"110115","label":"大兴区"}}`type JsonData struct {Province JsonData2 `json:"province"`City     JsonData2 `json:"city"`District JsonData2 `json:"district"`
}type JsonData2 struct {Value string `json:"value"`Label string `json:"label"`
}// json解码
func JsonDecode() {//json解码jsondata := JsonData{}_ = json.Unmarshal([]byte(jsonstr), &jsondata)fmt.Println(jsondata.Province.Label)fmt.Println(jsondata.City.Label)fmt.Println(jsondata.District.Label)
}

二、适用于json数据的结构未知的情况下

1、使用map

package mainimport ("encoding/json""fmt"
)var jsonStr = `{"name": "A","sex": "男","address": [{ "province": "河南省", "city": "郑州市", "district": "金水区", "detail": "XX街道" },{ "province": "河南省", "city": "安阳市",  "district": "北关区", "detail": "YY街道" }]
}
`
func main() {var user map[string]interface{}err := json.Unmarshal([]byte(jsonStr), &user)if err != nil {panic("解析失败")}fmt.Printf("名字：%s\n", user["name"].(string))fmt.Printf("性别：%s\n", user["sex"].(string))for i, address := range user["address"].([]interface{}) {addr := address.(map[string]interface{})fmt.Printf("地址%d：%s,%s,%s %s\n", i, addr["province"].(string), addr["city"].(string), addr["district"].(string), addr["detail"].(string))}
}

2、使用三方包

1、github.com/bitly/go-simplejson

package mainimport ("fmt""github.com/bitly/go-simplejson"
)var jsonStr := `{"name": "A","sex": "男","address": [{ "province": "河南省", "city": "郑州市", "district": "金水区", "detail": "XX街道" },{ "province": "河南省", "city": "安阳市",  "district": "北关区", "detail": "YY街道" }]}`func main() {// github.com/bitly/go-simplejsonjst, err := simplejson.NewJson(jsonStr)if err != nil {panic("解析失败")}name, _ := jst.Get("name").String()sex, _ := jst.Get("sex").String()fmt.Printf("名字：%s\n", name)fmt.Printf("性别：%s\n", sex)for i, v := range jst.Get("address").MustArray() {ads := v // v等同于jst.Get("address").GetIndex(i)province, _ := ads.Get("province").String()city, _ := ads.Get("city").String()district, _ := ads.Get("district").String()detail, _ := ads.Get("detail").String()fmt.Printf("地址%d：%s,%s,%s %s\n", i, province, city, district, detail)}
}

2、github.com/spf13/viper

1、要通过viper.SetConfigType("json")函数指定要解析数据的格式，否则即使viper.ReadConfig没有报错，解析后也没有返回结果

2、方法viper.Get()，viper.GetString()，viper.GetBool()等等可以方便获取键值，同时对于键值的类型也能很好的判断

package mainimport ("fmt""strings""github.com/spf13/viper"
)var jsonstr= `{"name": "tian","married": false,"address": {"city": "beijing","country": "China"}}`
func main() {// 指定配置的类型为jsonviper.SetConfigType("json")// 读取数据if err := viper.ReadConfig(strings.NewReader(jsonstr)); err != nil {fmt.Println(err)}fmt.Printf("数据的所有键值: %v\n", viper.AllKeys())fmt.Printf("解析后的数据：%v\n", viper.AllSettings())fmt.Printf("The name is %s and the country is %s\n", viper.Get("name"), viper.Get("address.country"))
}

3、github.com/thedevsaddam/gojsonq

查询name之后，调用了一次Reset()方法。因为jsonq在调用Find方法时，内部会记录当前的点，下一个查询会从上次记录的点开始

package mainimport ("fmt""github.com/thedevsaddam/gojsonq/v2"
)var jsonstr = `{"name": "sam","sex": false,"address": {"city": "北京","area": "中国"}}`
func main() {jst:= gojsonq.New().FromString(jsonstr)namestr := jst.Find("name").(string)jst.Reset()citystr := jst.Find("address.city")fmt.Printf("The name is %s and the city is %v", namestr, citystr)
}