33. golang中struct、json、map互相转化2

package main

import (
   "database/sql"
   "encoding/json"
   "fmt"
   "github.com/gogf/gf/encoding/gjson"
   "github.com/gogf/gf/frame/g"
   "github.com/gogf/gf/os/glog"
   "reflect"
)

func main()  {
   //JsonToStructDemo()
}

func db_to_json(){
   // 数据库数据转成json字符串输出
 db := g.DB("local")
   r, err:= db.Table("data_all").Where("name=?", "ad1909").One()
   fmt.Println(sql.ErrNoRows)
   if err != nil && err == sql.ErrNoRows {
      err = nil
 }

   //字符串数据转json对象
 mjson,_ :=json.Marshal(r)
   mString :=string(mjson)
   fmt.Println(mString)
   if k, err := gjson.DecodeToJson([]byte(mString)); err != nil {
      glog.Error(err)
   } else {
      fmt.Println(k.Get("name"))
   }
}

// json 转其他格式
func jsonstr_to_other(){
   data :=
      `{
         "users" : {
            "count" : 100,
            "list"  : [
               {"name" : "小明",  "score" : 60},
               {"name" : "John", "score" : 99.5}
            ]
         }
      }`
     if j, err := gjson.DecodeToJson([]byte(data)); err != nil {
         glog.Error(err)
      } else {

      //==========转json 字符串============================

      c, _ := j.ToJson()
      fmt.Println("JSON:")
      fmt.Println(string(c))
      fmt.Println("======================")

      fmt.Println("XML:")
      c, _ = j.ToXmlIndent()
      fmt.Println(string(c))
      fmt.Println("======================")

      fmt.Println("YAML:")
      c, _ = j.ToYaml()
      fmt.Println(string(c))
      fmt.Println("======================")

      fmt.Println("TOML:")
      c, _ = j.ToToml()
      fmt.Println(string(c))
   }
}

// 遍历json
func json_bianli(){
   data :=
      `{
         "users" : {
            "count" : 100,
            "list"  : [
               {"name" : "小明",  "score" : 60},
               {"name" : "John", "score" : 99.5}
            ]
         }
      }`
 if j, err := gjson.DecodeToJson([]byte(data)); err != nil {
         glog.Error(err)
      } else {

      //=========================解析成json 两种方法=================

      //=============方法1==================================
 for _, v := range j.GetArray("users.list") {
         fmt.Println(v.(map[string]interface{})["name"])        //需要强转
 }
      //=============方法2==================================
 for _, v := range j.GetJsons("users.list") {
         fmt.Println(v.Get("name"))                    //直接解析
 }

      fmt.Println("John Score:", j.GetFloat32("users.list.1.score"))
      fmt.Println("John Score:", j.GetInt("users.count"))

   }
}

//=========================================（JSON <--->map） =======================================================
/*
map  =======> JSON字符串
*/

//例子1
func Map_To_Json_1(){
   m :=map[string]string{"type":"10","msg":"hello."}
   mjson,_ :=json.Marshal(m)
   mString :=string(mjson)
   fmt.Printf("print mString:%s",mString)
}
//例子2
func Map_To_Json_2(){
   mapInstances := []map[string]interface{}{}
   instance_1 := map[string]interface{}{"name": "John", "age": 10}
   instance_2 := map[string]interface{}{"name": "Alex", "age": 12}
   mapInstances = append(mapInstances, instance_1, instance_2)
   jsonStr, err := json.Marshal(mapInstances)

   if err != nil {
      fmt.Println("MapToJsonDemo err: ", err)
   }
   fmt.Println(string(jsonStr))
}


/*
 JSON字符串 =======>  map
*/

//例子1
func JsonToMapDemo() {
   jsonStr := `{"name": "jqw","age": 18}`
 var mapResult map[string]interface{}
   err := json.Unmarshal([]byte(jsonStr), &mapResult)
   if err != nil {
      fmt.Println("JsonToMapDemo err: ", err)
   }
   fmt.Println(mapResult)
}

//=========================================（JSON <--->map） =======================================================

//=========================================（JSON <--->结构体） =======================================================

type IT struct {
   Address   string   `json:"address"`
 Languages []string `json:"languages"` //二次编码
 Status    bool     `json:"isok"`
 Price     float64  `json:"price"`
}
/*
JSON=======>结构体
*/

//例子1
func Json_to_Struct(){
   jsonBuf := `
      {
      "address": "北京",
      "languages": [
         "Golang",
         "PHP",
         "Java",
         "Python"
      ],
      "status": true,
      "price": 666.666
   }`
 var tmp IT                                   //定义一个结构体变量
 err := json.Unmarshal([]byte(jsonBuf), &tmp) //第二个参数要地址传递
 if err != nil {
      fmt.Println("err = ", err)
      return
 }
   fmt.Println("tmp = ", tmp)
   fmt.Printf("tmp = %+v\n", tmp)

   /*
   tmp =  {北京 [Golang PHP Java Python] false 666.666}
   tmp = {Address:北京 Languages:[Golang PHP Java Python] Status:false Price:666.666}

   */
}



//例子2   使用别名
type People struct {
   Name string `json:"name_title"`
 Age int `json:"age_size"`
}
func JsonToStructDemo(){
   jsonStr := `
   {
   "name_title": "jqw",
   "age_size":12
   }`
 var people People
 err:=json.Unmarshal([]byte(jsonStr), &people)
   if err != nil {
      fmt.Println("err = ", err)
      return
 }
   fmt.Println(people)
   fmt.Printf("tmp = %+v\n", people)
}


/*
   结构体=======>JSON
*/
// 例子1
func Struct_To_Json() {

   //定义一个结构体变量，同时初始化
 s := IT{"itcast", []string{"Golang", "PHP", "Java", "C++"}, true, 666.666}

   //编码，根据内容生成json文本
   //buf, err := json.Marshal(s)
   //buf =  {"subjects":["Golang","PHP","Java","C++"],"IsOk":"true","Price":"666.666"}
 buf, err := json.MarshalIndent(s, "", "    ") //格式化编码
 if err != nil {
      fmt.Println("err = ", err)
      return
 }

   fmt.Println("buf = ", string(buf))

   /*
   buf =  {
      "address": "itcast",
      "languages": [
         "Golang",
         "PHP",
         "Java",
         "C++"
      ],
      "isok": true,
      "price": 666.666
   }

   */
}


//=========================================（JSON <--->结构体） ========================================================



//=========================================[]interface{}转json =======================================================
func interface_to_json(){
   var s []interface{}
   s = append(s,5)
   s = append(s,[]string{"Golang", "PHP", "Java", "Python"})
   s = append(s,map[string]string{"hello":"world"})
   result, err := json.MarshalIndent(s, "", "    ")
   if err != nil {
      fmt.Println("err = ", err)
      return
 }
   fmt.Println("result = ", string(result))
}

//=========================================[]interface{}转json =======================================================

//=========================================struct=>map=======================================================


//需要安装一个第三方库
//在命令行中运行： go get github.com/goinggo/mapstructure

func Map2Struct() {
   mapInstances := make(map[string]interface{})
   mapInstances["Name"] = "amy"
 mapInstances["ID"] = 7
 mapInstances["Age"] = 18

 var account Account
 err := mapstructure.Decode(mapInstances, &account)
   if err != nil {
      fmt.Println(err)
   }

   fmt.Println(account)
}

func Struct2Map() {
   account := Account{
      Name: "amy",
 ID:   007,
 Age:  18,
 }
   obj1 := reflect.TypeOf(account)
   obj2 := reflect.ValueOf(account)
   var data = make(map[string]interface{})
   for i := 0; i < obj1.NumField(); i++ {
      data[obj1.Field(i).Name] = obj2.Field(i).Interface()
   }

   fmt.Println(data)
}
//=========================================struct=>map=======================================================