2020-11-10：golang中的接口，类型不空，值为空，如何判断是nil？

package main

import (
    "fmt"
    "reflect"
)

type Person struct {
    Name string
}

func (*Person) GetName() {

}

type ITester interface {
    GetName()
}

func main() {
    var i interface{} = nil //空值
    fmt.Println("空值")
    fmt.Println("==判断：", i == nil)
    fmt.Println("异常判断：", InterfaceIsNil1(i))
    fmt.Println("类型判断：", InterfaceIsNil2(i))
    fmt.Println("-----------")
    i = []int(nil) //切片
    fmt.Println("切片")
    fmt.Println("==判断：", i == nil)
    fmt.Println("异常判断：", InterfaceIsNil1(i))
    fmt.Println("类型判断：", InterfaceIsNil2(i))
    fmt.Println("-----------")
    i = map[int]int(nil) //映射
    fmt.Println("映射")
    fmt.Println("==判断：", i == nil)
    fmt.Println("异常判断：", InterfaceIsNil1(i))
    fmt.Println("类型判断：", InterfaceIsNil2(i))
    fmt.Println("-----------")
    i = chan int(nil) //通道
    fmt.Println("通道")
    fmt.Println("==判断：", i == nil)
    fmt.Println("异常判断：", InterfaceIsNil1(i))
    fmt.Println("类型判断：", InterfaceIsNil2(i))
    fmt.Println("-----------")
    i = (func())(nil) //函数
    fmt.Println("函数")
    fmt.Println("==判断：", i == nil)
    fmt.Println("异常判断：", InterfaceIsNil1(i))
    fmt.Println("类型判断：", InterfaceIsNil2(i))
    fmt.Println("-----------")
    i = (*int)(nil) //指针
    fmt.Println("指针")
    fmt.Println("==判断：", i == nil)
    fmt.Println("异常判断：", InterfaceIsNil1(i))
    fmt.Println("类型判断：", InterfaceIsNil2(i))

}

//异常判断
func InterfaceIsNil1(i interface{}) bool {
    ret := i == nil

    if !ret { //需要进一步做判断
        defer func() {
            recover()
        }()
        ret = reflect.ValueOf(i).IsNil() //值类型做异常判断，会panic的
    }

    return ret
}

//类型判断
func InterfaceIsNil2(i interface{}) bool {
    ret := i == nil

    if !ret { //需要进一步做判断
        vi := reflect.ValueOf(i)
        kind := reflect.ValueOf(i).Kind()
        if kind == reflect.Slice ||
            kind == reflect.Map ||
            kind == reflect.Chan ||
            kind == reflect.Interface ||
            kind == reflect.Func ||
            kind == reflect.Ptr {
            return vi.IsNil()
        }
    }

    return ret
}