[大数据][GO] json字符串与struct、map的相互转换

json字符串与struct、map的相互转换是业务开发中非常常用的，需要好好总结：

json和struct的转换

package main

import (
	"encoding/json"

	"github.com/davecgh/go-spew/spew"
)

type User struct {
	Name string
	Age int
}

func main() {
	user := User{
		Name: "王思聪",
		Age: 20,
	}
	// struct 转 json string
	inBytes,_ := json.Marshal(&user)
	jsonString := string(inBytes)
	spew.Dump(jsonString)

	// json string 转 struct 
	user2 := User{}
	_ = json.Unmarshal([]byte(jsonString),&user2)
	spew.Dump(user2)

	// 	(string) (len=29) "{\"Name\":\"王思聪\",\"Age\":20}"
	// 	(main.User) {
	// 		Name: (string) (len=9) "王思聪",
	//		Age: (int) 20
	// }
}

## json和map的转换

package main

import (
	"encoding/json"

	"github.com/davecgh/go-spew/spew"
)

func main() {
	// map[string]interface{} 转 json string
	params := map[string]interface{}{
		"a": 123,
		"b": "战三",
	}
	inBytes,_ := json.Marshal(params)
	jsonString := string(inBytes)
	spew.Dump(jsonString)

	// json string 转 map[string]interface{}
	params2 := map[string]interface{}{}
	_ = json.Unmarshal([]byte(jsonString),&params2)
	spew.Dump(params2)
	for _, v := range params2 {
		spew.Println(v)
	}

	// 	(string) (len=22) "{\"a\":123,\"b\":\"战三\"}"
	// 	(map[string]interface {}) (len=2) {
	//  	(string) (len=1) "a": (float64) 123,
	//  	(string) (len=1) "b": (string) (len=6) "战三"
	// 	}
	// 	123
	// 	战三
}