go-json

将map或struct转为jsonstr：

package main

import (
	"encoding/json"
	"fmt"
)
func main() {
	mymap := make(map[string]string)
	mymap["name"] = "zhang"
	mymap["addr"] = "China"

	jsonstr, _ := json.Marshal(mymap) // Marsh返回[]byte类型
	fmt.Println(string(jsonstr))
}

结果{"addr":"China","name":"zhang"}

将jsonstr转为map或struct

package main

import (
	"encoding/json"
	"fmt"
)

json_input := `{"phone":"188","age":"30"}`
err := json.Unmarshal([]byte(json_input), &mymap )  // 第二个参数必须为指针类型
if err != nil {
	fmt.Println(err)
	os.Exit(1)
}
fmt.Println(mymap)

结果map[addr:London name:wang]

使用Encoder生成jsonstr

package main

import (
	"bytes"
	"encoding/json"
	"fmt"
)

func main() {
	mymap := make(map[string]string)
	mymap["name"] = "zhang"
	mymap["addr"] = "China"

	buffer := new(bytes.Buffer)
	json.NewEncoder(buffer).Encode(mymap)
	fmt.Println(buffer.String())
}

结果{"addr":"China","name":"zhang"}

使用Decoder解析jsonstr

package main

import (
	"bytes"
	"encoding/json"
	"fmt"
)

func main() {
	json_input := `{"name":"wang","addr":"London"}`
	buffer := new(bytes.Buffer)
	buffer.WriteString(json_input)
	json.NewDecoder(buffer).Decode(&mymap)
	fmt.Println(mymap)
}

结果map[addr:London name:wang]

注意事项

一般jsonstr为{"Name":"Eve","Age":6,"Addr":"shanghai","Parents":["Alice","Bob"]}这种样式的，解析时可以直接定义一个map[string]interface{}类型来接收，更为通用的是interface{}来接收：

jsonData := []byte(`{"Name":"Eve","Age":6,"Parents":["Alice","Bob"]}`)

var v interface{}
json.Unmarshal(jsonData, &v)
data := v.(map[string]interface{})

for k, v := range data {
    switch v := v.(type) {
    case string:
        fmt.Println(k, v, "(string)")
    case float64:
        fmt.Println(k, v, "(float64)")
    case []interface{}:
        fmt.Println(k, "(array):")
        for i, u := range v {
            fmt.Println("    ", i, u)
        }
    default:
        fmt.Println(k, v, "(unknown)")
    }
}