package main

import "fmt"
import "reflect"
import "encoding/json"

func main(){

	//1、结构体转为json
	res := new(Response)
	res.Code = 200
	res.Message = "success"
	fmt.Println(res)
	fmt.Println("将结构体生成json")
	//转化完默认是[]uint8类型,需要转换为string类型才能正常输出json
	cont,_ := json.Marshal(res)
	fmt.Println(string(cont))	//	输出json	

	//2、map转为json
	map1 := make(map[string]string)
	fmt.Println(map1)
	map1["name"] = "maozedong"
	map1["address"] = "湖南"
	fmt.Println(map1)
	map_json, _ := json.Marshal(map1)
	fmt.Println(reflect.TypeOf(map_json))	//[]uint8
	fmt.Println(string(map_json))	//输出json



	//1、json转map
	json_string := `[{"Level":"debug","Msg":"订单不存在"},{"Level":"error","Msg":"Logic error"}]`
	var m1 []map[string]string
	json.Unmarshal([]byte(json_string), &m1)
	fmt.Println("json 转为map:")
	fmt.Println(m1)	//输出map

	//2、json转结构体
	var json_struct []S1_struct
	json.Unmarshal([]byte(json_string), &json_struct)
	fmt.Println(json_struct)	//输出结构体

	//3、json结构体互转还支持tag映射
	var json_struct2 []S2_struct
	json.Unmarshal([]byte(json_string), &json_struct2)
	fmt.Println(json_struct2)	//输出映射后的结构体
	for _,item := range json_struct2 {
		fmt.Println(item.Message)
	}
	
	//4、同理，结构体转换为json也支持tag映射
	var struct3 S2_struct
	struct3.Message = "hello message"
	struct3.LevelString = "hello level"
	content,_ := json.Marshal(struct3)
	fmt.Println(string(content))	//json的键将分别被映射为Level，Msg
}

type Response struct{
	Code int
	Message string
}

type S1_struct struct{
	Level string
	Msg string
}

type S2_struct struct{
	LevelString string	`json:"Level"`	//json里的level映射到LevelString
	Message string 		`json:"Msg"`	//json里的Msg映射到Message
}