细说Golang的JSON解析
golang JSON技巧
Go - 如何解析 JSON 数据?mapstruct包
读写结构体
//写[obj,]
type user struct {
Name string `json:"name"`
Age int `json:"age"`
}
m:= []user{
{"m1",1},
{"m2",2},
}
f, _ := os.Create("./data.txt")
b, _ := json.Marshal(m)
f.Write(b)
defer f.Close()
//读[obj,]
var arr []user
b, _ := ioutil.ReadFile("./data.txt") //会自动帮你初始化arr
json.Unmarshal(b, &arr)
fmt.Printf("%T,%v", arr, arr)
转为json忽略字段
转回来,采用struct默认值
鼠标停留在json.Marshal上看下帮助就一目了然了.
tag多数为struct转json时生效
/*
// Field appears in JSON as key "myName".
Field int `json:"myName"` //理解为 Field in json
// Field appears in JSON as key "myName" and
// the field is omitted from the object if its value is empty,
// as defined above.
Field int `json:"myName,omitempty"`
// Field appears in JSON as key "Field" (the default), but
// the field is skipped if empty.
// Note the leading comma.
Field int `json:",omitempty"`
// Field is ignored by this package.
Field int `json:"-"`
// Field appears in JSON as key "-".
Field int `json:"-,"`
*/
后台出去时
// 出去时, 如果结构体是什么(有些字段指定了值,有些没有),就构建出什么样子的json
type user struct {
Age int `json:"age"`
Name string `json:"name"`
//Age int `json:"age,omitempty"`
}
func main() {
u := user{
Name: "m1",
}
b, _ := json.Marshal(u)
fmt.Println(string(b))
}
//{"age":0,"name":"m1"}
//如果是零值时,毙掉这个字段
//omitempty的字段: 如果改字段为零值,则毙掉这个字段
//结构体加了omitempty字段, 则出去时, 如果struct实例字段为零值, 则会毙掉这个字段
type user struct {
Name string `json:"name"`
//Age int `json:"age"`
Age int `json:"age,omitempty"`
}
func main() {
u := user{
Name: "m1",
Age: 0,
}
b, _ := json.Marshal(u)
fmt.Println(string(b))
}
//{"name":"m1"}
// - 毙掉这个字段
type user struct {
Name string `json:"name"`
//Age int `json:"age"`
//Age int `json:"age,omitempty"`
Age int `json:"-"`
}
func main() {
u := user{
Name: "m1",
Age: 0,
}
b, _ := json.Marshal(u)
fmt.Println(string(b))
}
//{"name":"m1"}
// 转换结构体类型(如果转换失败,则保留原有类型,不会报错)
type user struct {
Name string `json:"name"`
//Age int `json:"age"`
//Age int `json:"age,omitempty"`
//Age int `json:"-"`
Age int `json:",string"`
}
func main() {
u := user{
Name: "m1",
Age: 22,
}
b, _ := json.Marshal(u)
fmt.Println(string(b))
}
//{"name":"m1","Age":"22"}
前台进来时
// 进来时, 如果json类型和struct类型不匹配,则报错
type user struct {
Name string `json:"name"`
Age int `json:"age"`
}
func main() {
var jsonStr = `
{
"name":"m1",
"age":"22"
}
`
var u user
err := json.Unmarshal([]byte(jsonStr), &u)
if err != nil {
fmt.Println(err)
}
fmt.Println(u)
}
//json: cannot unmarshal string into Go struct field user.age of type int
//{m1 0}
// 进来时,如果json字段里没有, 则struct以零值填充
type user struct {
Name string `json:"name"`
Age int `json:"age"`
}
func main() {
var jsonStr = `
{
"name":"m1"
}
`
var u user
err := json.Unmarshal([]byte(jsonStr), &u)
if err != nil {
fmt.Println(err)
}
fmt.Println(u)
}
//{m1 0}
原文地址:https://www.cnblogs.com/iiiiiher/p/12118352.html
时间: 2024-11-05 20:38:29