package main

import (
 "encoding/json"
 "fmt"
)

func main() {
 type Person struct {
 HelloWold    string
 LightWeightBaby string
 }
 var a = Person{HelloWold: "chenqionghe", LightWeightBaby: "muscle"}
 res, _ := json.Marshal(a)
 fmt.Printf("%s", res)
}

type Person struct {
 HelloWold    string `json:"hello_wold"`
 LightWeightBaby string `json:"light_weight_baby"`
}

package jsonconv

import (
 "bytes"
 "encoding/json"
 "log"
 "regexp"
 "strconv"
 "strings"
 "unicode"
)

/*************************************** 下划线json ***************************************/
type JsonSnakeCase struct {
 Value interface{}
}

func (c JsonSnakeCase) MarshalJSON() ([]byte, error) {
 // Regexp definitions
 var keyMatchRegex = regexp.MustCompile(`\"(\w+)\":`)
 var wordBarrierRegex = regexp.MustCompile(`(\w)([A-Z])`)
 marshalled, err := json.Marshal(c.Value)
 converted := keyMatchRegex.ReplaceAllFunc(
 marshalled,
 func(match []byte) []byte {
  return bytes.ToLower(wordBarrierRegex.ReplaceAll(
  match,
  []byte(`${1}_${2}`),
  ))
 },
 )
 return converted, err
}

/*************************************** 驼峰json ***************************************/
type JsonCamelCase struct {
 Value interface{}
}

func (c JsonCamelCase) MarshalJSON() ([]byte, error) {
 var keyMatchRegex = regexp.MustCompile(`\"(\w+)\":`)
 marshalled, err := json.Marshal(c.Value)
 converted := keyMatchRegex.ReplaceAllFunc(
 marshalled,
 func(match []byte) []byte {
  matchStr := string(match)
  key := matchStr[1 : len(matchStr)-2]
  resKey := Lcfirst(Case2Camel(key))
  return []byte(`"` + resKey + `":`)
 },
 )
 return converted, err
}

/*************************************** 其他方法 ***************************************/
// 驼峰式写法转为下划线写法
func Camel2Case(name string) string {
 buffer := NewBuffer()
 for i, r := range name {
 if unicode.IsUpper(r) {
  if i != 0 {
  buffer.Append('_')
  }
  buffer.Append(unicode.ToLower(r))
 } else {
  buffer.Append(r)
 }
 }
 return buffer.String()
}

// 下划线写法转为驼峰写法
func Case2Camel(name string) string {
 name = strings.Replace(name, "_", " ", -1)
 name = strings.Title(name)
 return strings.Replace(name, " ", "", -1)
}

// 首字母大写
func Ucfirst(str string) string {
 for i, v := range str {
 return string(unicode.ToUpper(v)) + str[i+1:]
 }
 return ""
}

// 首字母小写
func Lcfirst(str string) string {
 for i, v := range str {
 return string(unicode.ToLower(v)) + str[i+1:]
 }
 return ""
}

// 内嵌bytes.Buffer，支持连写
type Buffer struct {
 *bytes.Buffer
}

func NewBuffer() *Buffer {
 return &Buffer{Buffer: new(bytes.Buffer)}
}

func (b *Buffer) Append(i interface{}) *Buffer {
 switch val := i.(type) {
 case int:
 b.append(strconv.Itoa(val))
 case int64:
 b.append(strconv.FormatInt(val, 10))
 case uint:
 b.append(strconv.FormatUint(uint64(val), 10))
 case uint64:
 b.append(strconv.FormatUint(val, 10))
 case string:
 b.append(val)
 case []byte:
 b.Write(val)
 case rune:
 b.WriteRune(val)
 }
 return b
}

func (b *Buffer) append(s string) *Buffer {
 defer func() {
 if err := recover(); err != nil {
  log.Println("*****内存不够了！******")
 }
 }()
 b.WriteString(s)
 return b
}

func main() {
 type Person struct {
 HelloWold    string
 LightWeightBaby string
 }
 var a = Person{HelloWold: "chenqionghe", LightWeightBaby: "muscle"}
 res, _ := json.Marshal(jsonconv.JsonSnakeCase{a})
 fmt.Printf("%s", res)
}

func main() {
 type Person struct {
 HelloWold    string `json:"hello_wold"`
 LightWeightBaby string `json:"light_weight_baby"`
 }
 var a = Person{HelloWold: "chenqionghe", LightWeightBaby: "muscle"}
 res, _ := json.Marshal(jsonconv.JsonCamelCase{a})
 fmt.Printf("%s", res)
}