1.Map转JSON

package main
import (
"encoding/json"
"fmt"
)
func main() {
// map里面
map1 := map[string]string {
"name":"张三",
"age":"18",
"home":"北京",
}
// 将map解析成json
json1, err := json.Marshal(map1)
if err != nil {
fmt.Println(err.Error())
}
fmt.Printf("json1: %s 类型: %T \n",json1,json1)

map2 := map[string][]string {
"fruit": {"香蕉","葡萄"},
"coder":{"PHP","Go","Java"},
"likes":{"打游戏","看动漫"},
}
json2, err := json.Marshal(map2)
if err != nil {
fmt.Println(err.Error())
}
fmt.Printf("json2: %s 类型: %T \n",json2,json2)
}
/**输出
json1: {"age":"18","home":"北京","name":"张三"} 类型: []uint8
json2: {"coder":["PHP","Go","Java"],"fruit":["香蕉","葡萄"],"likes":["打游戏","看动漫"]} 类型: []uint8
*/

2. Json转Map

package main
import (
"encoding/json"
"fmt"
)
func main() {
json1 := `{"age":"18","home":"北京","name":"张三"}`
map1 := make(map[string]string)
err := json.Unmarshal([]byte(json1), &map1)
if err != nil {
fmt.Println(err.Error())
}
fmt.Printf("map1: %v T: %T\n",map1,map1)

json2 := `{"coder":["PHP","Go","Java"],"fruit":["香蕉","葡萄"],"likes":["打游戏","看动漫"]}`
map2 := make(map[string][]string)
err = json.Unmarshal([]byte(json2), &map2)
if err != nil {
fmt.Println(err.Error())
}
fmt.Printf("map2: %v T: %T\n",map2,map2)
}
/**输出
map1: map[age:18 home:北京 name:张三] T: map[string]string
map2: map[coder:[PHP Go Java] fruit:[香蕉 葡萄] likes:[打游戏 看动漫]] T: map[string][]string
*/

3.结构体转JSON

3.1 无字段标签

结构体转换成JSON在开发中经常会用到。encoding/json包是通过反射机制来实现编解码的,因此结构体必须导出所转换的字段,没有导出的字段不会被encoding/json包解析。

package main
import (
"encoding/json"
"fmt"
)
type Student struct {
Name string
Age int
Class string
phone string //小写字段,则不是会导出
}
func main() {
s := Student{
Name: "张三",
Age: 17,
Class: "三年级",
phone: "17600112222",
}
json1, err := json.Marshal(s)
if err != nil {
fmt.Println(err.Error())
}
fmt.Printf("json: %s \n",json1)
}
// 输出 json: {"Name":"张三","Age":17,"Class":"三年级"}

3.2 有字段标签

json包在解析结构体时,如果遇到keyJSON的字段标签,则会按照一定规则解析该标签。

package main
import (
"encoding/json"
"fmt"
)
// 定义一个学生结构体
type Student struct {
Name string `json:"_name"` // 字段标签的语法
Age int `json:"_age"`
Class string `json:"-"` // 不解析
Phone string `json:"phone"`
Score float32 // 没有标签时,则用字段名
}
func main() {
s := Student{
Name: "张三",
Age: 17,
Class: "三年级",
Phone: "17600112222",
Score: 88.5,
}
json1, err := json.Marshal(s)
if err != nil {
fmt.Println(err.Error())
}
fmt.Printf("json: %s \n",json1)
}
// 输出-> json: {"_name":"张三","_age":17,"phone":"17600112222","Score":88.5}
1.规则总结
  • 有标签名时,标签名会作为key
  • 没有标签时,则会使用字段名。
  • 有标签名时,但是标签名的值为-,则不会导出

3.3 匿名字段

json包在解析匿名字段时,会将匿名字段的字段当成该结构体的字段处理。

package main
import (
"encoding/json"
"fmt"
)
type Student struct {
Name string `json:"_name"`
Age int `json:"_age"`
Top // 匿名字段
}
type Top struct {
Sort int `json:"sort"`
Score float64
Class string
}
func main() {
s := Student{
Name: "张三",
Age: 18,
Top: Top{1,99.5,"一年级"},
}
json1, err := json.Marshal(s)
if err != nil {
fmt.Println(err.Error())
}
fmt.Printf("json: %s \n",json1)
}
//输出-> json: {"_name":"张三","_age":18,"sort":1,"Score":99.5,"Class":"一年级"}

4.JSON转结构体

JSON可以转换成结构体。同编码一样,json包是通过反射机制来实现解码的,因此结构体必须导出所转换的字段,不导出的字段不会被json包解析。另外解析时不区分大小写。

package main
import (
"encoding/json"
"fmt"
)
type Student struct {
Name string `json:"_name"`
Age int `json:"_age"`
Top // 匿名字段
}
type Top struct {
Sort int `json:"sort"`
Score float64
Class string
}
func main(){
student := Student{}
js := `{"_name":"张三","_age":18,"sort":1,"Score":99.5,"Class":"一年级"}`
err := json.Unmarshal([]byte(js), &student)
if err != nil {
fmt.Println(err.Error())
}
fmt.Printf("v: %+v t: %T \n",student,student)
}
// 输出: v: {Name:张三 Age:18 Top:{Sort:1 Score:99.5 Class:一年级}} t: main.Student

5.切片转JSON

package main
import (
"encoding/json"
"fmt"
)
func main(){
student := []string {
"张三",
"李四",
"小米",
}
marshal, err := json.Marshal(student)
if err != nil {
fmt.Println(err.Error())
}
fmt.Printf("v :%s T:%T",marshal,marshal)
}
// 输出 v :["张三","李四","小米"] T:[]uint8

6.JSON转切片

package main
import (
"encoding/json"
"fmt"
)
func main(){
json1 := `["张三","李四","小米"]`
var sc []string
err := json.Unmarshal([]byte(json1), &sc)
if err != nil {
fmt.Println(err.Error())
}
fmt.Printf("v :%v T:%T",sc,sc)
}
// 输出: v :[张三 李四 小米] T:[]string