JSON
JSON (JavaScript Object Notation, JS Object Notation) is a lightweight data exchange format. https://www.json.cn/
- Grammar rules
In the JS language, everything is an object. Therefore, any supported type can be represented by JSON. - Key/value pair
JSON key-value pair is a way to save JS objects. The key name in the key/value pair combination is written in front and wrapped in double quotation marks "", separated by a colon:, and then followed by the value
{"firstName": "Json"}
- Serialization of
json JSON serialization refers to the operation of serializing data types with a key-value structure (such as structure, map, and slice) into json strings.
- Structure json serialization:
type Monster struct {
Name string
Age int
Birthday string
Sal float64
Skill string
}
func main() {
monster := Monster{
Name :"牛魔王",
Age : 500 ,
Birthday : "2011-11-11",
Sal : 8000.0,
Skill : "牛魔拳",
}
//将monster 序列化
data, err := json.Marshal(&monster) //..
if err != nil {
fmt.Printf("序列号错误 err=%v\n", err)
}
//输出序列化后的结果
fmt.Printf("monster序列化后=%v\n", string(data))
}
- map json serialization:
func main() {
//定义一个map
var a map[string]interface{}
//使用map,需要make
a = make(map[string]interface{})
a["name"] = "红孩儿"
a["age"] = 30
a["address"] = "洪崖洞"
//将a这个map进行序列化
//将monster 序列化
data, err := json.Marshal(a)
if err != nil {
fmt.Printf("序列化错误 err=%v\n", err)
}
//输出序列化后的结果
fmt.Printf("a map 序列化后=%v\n", string(data))
}
- Slice json serialization:
func main() {
var slice []map[string]interface{}
var m1 map[string]interface{}
//使用map前，需要先make
m1 = make(map[string]interface{})
m1["name"] = "jack"
m1["age"] = "7"
m1["address"] = "北京"
slice = append(slice, m1)
var m2 map[string]interface{}
//使用map前，需要先make
m2 = make(map[string]interface{})
m2["name"] = "tom"
m2["age"] = "20"
m2["address"] = [2]string{"墨西哥","夏威夷"}
slice = append(slice, m2)
//将切片进行序列化操作
data, err := json.Marshal(slice)
if err != nil {
fmt.Printf("序列化错误 err=%v\n", err)
}
//输出序列化后的结果
fmt.Printf("slice 序列化后=%v\n", string(data))
}
- Basic data type serialization
Serialization of basic data types does not make much sense
func main() {
var num1 float64 = 2345.67
//对num1进行序列化
data, err := json.Marshal(num1)
if err != nil {
fmt.Printf("序列化错误 err=%v\n", err)
}
//输出序列化后的结果
fmt.Printf("num1 序列化后=%v\n", string(data))
}
Note
For the serialization of the structure, if we want the name of the serialized key to be redesigned by ourselves, then we can assign a tag tag to the struct.
type Monster struct {
Name string `json:"monster_name"` //反射机制
Age int `json:"monster_age"`
Birthday string `json:"monster_birthday"`
Sal float64 `json:"monster_sal"`
Skill string `json:"monster_skill"`
}
func testStruct() {
//演示
monster := Monster{
Name :"牛魔王",
Age : 500 ,
Birthday : "2011-11-11",
Sal : 8000.0,
Skill : "牛魔拳",
}
//将monster 序列化
data, err := json.Marshal(&monster) //..
if err != nil {
fmt.Printf("序列号错误 err=%v\n", err)
}
//输出序列化后的结果
fmt.Printf("monster序列化后=%v\n", string(data))
}
- json deserialization
json deserialization refers to the operation of deserializing json strings into corresponding data types (such as structure, map, slice)
- json deserialization structure:
type Monster struct {
Name string
Age int
Birthday string //....
Sal float64
Skill string
}
//演示将json字符串，反序列化成struct
func main() {
//说明str 在项目开发中，是通过网络传输获取到.. 或者是读取文件获取到
str := "{\"Name\":\"牛魔王~~~\",\"Age\":500,\"Birthday\":\"2011-11-11\",\"Sal\":8000,\"Skill\":\"牛魔拳\"}"
//定义一个Monster实例
var monster Monster
err := json.Unmarshal([]byte(str), &monster)
if err != nil {
fmt.Printf("unmarshal err=%v\n", err)
}
fmt.Printf("反序列化后 monster=%v monster.Name=%v \n", monster, monster.Name)
}
- json deserialize map:
func main() {
str := "{\"address\":\"洪崖洞\",\"age\":30,\"name\":\"红孩儿\"}"
//定义一个map
var a map[string]interface{}
//反序列化
//注意：反序列化map,不需要make,因为make操作被封装到 Unmarshal函数
err := json.Unmarshal([]byte(str), &a)
if err != nil {
fmt.Printf("unmarshal err=%v\n", err)
}
fmt.Printf("反序列化后 a=%v\n", a)
}
- json deserialize slice:
func main() {
str := "[{\"address\":\"北京\",\"age\":\"7\",\"name\":\"jack\"}," +
"{\"address\":[\"墨西哥\",\"夏威夷\"],\"age\":\"20\",\"name\":\"tom\"}]"
//定义一个slice
var slice []map[string]interface{}
//反序列化，不需要make,因为make操作被封装到 Unmarshal函数
err := json.Unmarshal([]byte(str), &slice)
if err != nil {
fmt.Printf("unmarshal err=%v\n", err)
}
fmt.Printf("反序列化后 slice=%v\n", slice)
}