<17> go json

go里的encoding/json 包专门处理json

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

type Response1 struct {
    Page   int
    Fruits []string
}

type Response2 struct {
    Page   int      `json:"page"`
    Fruits []string `json:"fruits"`
}

func main() {
    fmt.Println("Start Main func()")
    // 单个常见类型的处理
    bolB, _ := json.Marshal(true)
    fmt.Println(string(bolB))
    intB, _ := json.Marshal(1)
    fmt.Println(string(intB))

    fltB, _ := json.Marshal(2.34)
    fmt.Println(string(fltB))
    strB, _ := json.Marshal("gopher")
    fmt.Println(string(strB))

    slcD := []string{"apple", "peach", "pear"}
    slcB, _ := json.Marshal(slcD)
    fmt.Println(string(slcB))

    mapD := map[string]int{"apple": 5, "lettuce": 7}
    mapB, _ := json.Marshal(mapD)
    fmt.Println(string(mapB))
    // struct的处理
    res1D := &Response1{
        Page:   1,
        Fruits: []string{"apple", "peach", "pear"}}
    res1B, _ := json.Marshal(res1D)
    fmt.Println(string(res1B))

    res2D := &Response2{
        Page:   1,
        Fruits: []string{"apple", "peach", "pear"}}
    res2B, _ := json.Marshal(res2D)
    fmt.Println(string(res2B))

    byt := []byte(`{"num":6.13,"strs":["a","b"]}`)
    var dat map[string]interface{}
    if err := json.Unmarshal(byt, &dat); err != nil {
        panic(err)
    }
    fmt.Println(dat)
    fmt.Println(dat["num"])

    num := dat["num"].(float64)
    fmt.Println(num)

    strs := dat["strs"].([]interface{})
    str1 := strs[0].(string)
    fmt.Println(str1)

    // json => struct
    str := `{"page": 1, "fruits": ["apple", "peach"]}`
    res := Response2{}
    json.Unmarshal([]byte(str), &res)
    fmt.Println(res)
    fmt.Println(res.Fruits[0])

    enc := json.NewEncoder(os.Stdout)
    d := map[string]int{"apple": 5, "lettuce": 7}
    enc.Encode(d)

    ares2D := &Response2{
        Page:   1,
        Fruits: []string{"apple", "peach", "pear"}}
    ares2B, _ := json.MarshalIndent(ares2D, "a", "b")
    fmt.Println(string(ares2B))
}