Go类型断言demo

package main

import (
    "bytes"
    "encoding/json"
    "fmt"
    "io"
    "net/http"
    "time"
    "github.com/unknwon/com"
)

//空接口
func test1() {
    a := make(map[string]interface{}, 20)
    a["name"] = "haha"
    a["age"] = 20
    a["merried"] = true
    a["hobby"] = []string{"喝", "跳", "rap"}
    fmt.Printf("type:%T v:%#v\n", a["hobby"],a["hobby"])
    v,ok := a["hobby"].([]string)
    if(!ok){
        fmt.Println("type is not map.") //type:[]string v:[]string{"喝", "跳", "rap"}
    }

    fmt.Println(v[0]) //喝

}

//接口作为函数的参数
func test2(a interface{}) {
    fmt.Printf("type:%T value:%v \n", a, a)
}

type resParamData struct {
    Code int         `json:"code"`
    Msg  string      `json:"Msg"`
    Data interface{} //方法一
}
type userinfo struct {
    Name string `json:"name"`
    Age  int    `json:"age"`
}

func test3() {
    var m = make(map[string]interface{}, 0)
    m["name"] = "test"
    m["age"] = 20
    var res resParamData
    res.Code = 200
    res.Msg = "ok"
    res.Data = m

    fmt.Println(res.Data)
    value, ok := res.Data.(map[string]interface{})
    if !ok {
        fmt.Println("It's not ok for type Order")
        return
    }
    fmt.Println("The value is ", value["name"])
    fmt.Println("The value is ", value["age"])
    fmt.Printf("type:%T value:%v\n", value["age"], value["age"])

}
func test4() {
    var uinfo = userinfo{
        Name: "lisi",
        Age:  18,
    }
    var resdata resParamData
    resdata.Code = 200
    resdata.Msg ="ok"
    resdata.Data = uinfo
    fmt.Println(resdata.Data)
    value, ok := resdata.Data.(userinfo)
    if !ok {
        fmt.Println("It's not ok for type Order")
        return
    }
    fmt.Println("The value is ", value.Name)
    fmt.Println("The value is ", value.Age)
    fmt.Printf("type:%T value:%v\n", value.Name, value.Name)
    fmt.Printf("type:%T value:%v\n", value.Age, value.Age)

}
type PostresData2 struct {
    Data   interface{} //方法一
    Errmsg string      `json:"errmsg"`
    Errno  int         `json:"errno"`
}
func test5() {
    var d PostresData2
    url := "https://api.ibanana.club/select/major/list_by_key?page=1&row=10&major_name=工程"
    res := SetGet(url)
    _ = json.Unmarshal([]byte(res), &d)
    fmt.Println(1111111111)
    fmt.Printf("type:%T value:%#v \n", d, d)
    fmt.Printf("type:%T value:%#v \n", d.Errno, d.Errno)
    fmt.Printf("type:%T value:%#v \n", d.Data, d.Data)
    value,ok:=d.Data.([]interface {})
    if !ok {
        fmt.Println("It's not ok for type major")
        return
    }
    for _,v:=range value{
        m,ok:=v.(map[string]interface {})
        if !ok {
            fmt.Println("It's not ok for type m")
            return
        }
        id:=com.StrTo(com.ToStr(m["id"])).MustInt64()
        fmt.Printf("type:%T value:%v\n",id, id) //type:int64 value:20
        fmt.Printf("type:%T value:%v\n", m["major_name"], m["major_name"]) //type:string value:交通工程
        //改变期值
        if(id==19){
            m["id"]=100
            m["major_name"]="edit value22"
        }
    }
    fmt.Println("GetTest")
    fmt.Println(d)
    //httpext.SuccessExt(ctx, d)
}

func main() {
    //test5()
    //test4()
    //test3()
    test1()
    //a := 12
    //test2(a)
    //test2(nil)
    //test2(false)
}
// Get ... 发送请求 ...
// url：         请求地址
// response：    请求返回的内容
func SetGet(url string) string {

    // 超时时间：5秒
    client := &http.Client{Timeout: 5 * time.Second}
    resp, err := client.Get(url)
    if err != nil {
        panic(err)
    }
    defer resp.Body.Close()
    var buffer [512]byte
    result := bytes.NewBuffer(nil)
    for {
        n, err := resp.Body.Read(buffer[0:])
        result.Write(buffer[0:n])
        if err != nil && err == io.EOF {
            break
        } else if err != nil {
            panic(err)
        }
    }

    return result.String()
}

test5接口的反参

{
    "code": 200,
    "data": {
        "Data": [
            {
                "id": 100,
                "major_name": "edit value22"
            },
            {
                "id": 20,
                "major_name": "交通工程"
            },
            {
                "id": 22,
                "major_name": "交通管理工程"
            },
            {
                "id": 23,
                "major_name": "交通设备与控制工程"
            },
            {
                "id": 46,
                "major_name": "信息工程"
            },
            {
                "id": 50,
                "major_name": "假肢矫形工程"
            },
            {
                "id": 53,
                "major_name": "光电信息科学与工程"
            },
            {
                "id": 63,
                "major_name": "农业工程"
            },
            {
                "id": 64,
                "major_name": "农业建筑环境与能源工程"
            },
            {
                "id": 66,
                "major_name": "农业水利工程"
            }
        ],
        "errmsg": "ok",
        "errno": 200
    },
    "msg": "ok"
}