GO系列(1)-interface{} 多参数... 封装继承多态

一. Interface{}

interface可以理解为iOS中的NSObject，是一种单独的类型

1. 其他类型与interface{}的互相转换

var v interface{} = 1
var s uint8 = 1
temp1 := int(s)
temp2 := v.(int)
fmt.Println(temp1,temp2)

2. interface{}转换为其他类型的断言

interface转换成具体类型调用方式：interfaceVar.(具体类型)

原理：断言

断言成功返回true，失败false

func testInterface2String()  {
   a := "tomxiang"
   v, ok := interface{}(a).(string)   // 将 a 转换为接口类型
   if ok {
      fmt.Printf("v type is %T\n", v)
   }
   fmt.Println(a)
}

二. 三个...

参考：https://geekr.dev/posts/go-func-params-and-return-values

XXX(args ... interface{})这种方式接收参数，如果你调用xxx(ids...), 会把ids直接传递过去，没有包装的开销。XXX(ids)这种会有包装开销，会申请个新切片，把ids作为切片第一个元素

1.1 切片正常传递

func testInterface1()  {
   var ids1 = []interface{}{1, 2.2, 3.4}
   printInterface1(ids1)
}

func printInterface1(vals []interface{}) {
   for _, val := range vals {
      fmt.Println(val)
   }
}

输出结果

1
2.2
3.4

1.2 接收的是新的切片0号元素

func testInterface2()  {
   var ids2 = []interface{}{1, 2.2, 3.4}
   printInterface2(ids2)
}
func printInterface2(vals ...interface{}) {
   for _, val := range vals {
      fmt.Println(val)
   }
}

输出结果：

[1 2.2 3.4]

1.3 接收的是新的切片

func testInterface3()  {
   var ids3 = []interface{}{1, 2.2, 3.4}
   printInterface3(ids3...)
}
func printInterface3(vals ...interface{}) {
   for _, val := range vals {
      fmt.Println(val)
   }
}

输出结果

1
2.2
3.4

三. 封装继承多态

package main

import "fmt"

func main()  {
    /*封装*/
    peo := new(People)
    peo.SetName("derek")
    peo.SetAge(22)
    fmt.Println(peo.GetName(),peo.GetAge())     //derek 22

    /*继承*/
    tea := Teacher{People{"derek-teacher",22},"911"}
    fmt.Println(tea.classroom,tea.name,tea.age)    //911 derek 22

    stu := Student{People{"derek-student",11},"919"}
    fmt.Println(stu.classroom,stu.name,stu.age)    //911 derek 22

    //tea.run()
    //stu.run()

    /*多态*/
    allrun(&tea)
    allrun(&stu)
}


type Live interface {
    run()
}
func allrun(live Live)  {
    live.run()
}

type People struct {
    name string
    age int
}

func (p *People) SetName(name string)  {
    p.name = name
}

func (p *People) SetAge(age int)  {
    p.age = age
}
func (p *People) run()  {
    fmt.Println("%v在跑步",p.name)
}
func (p *People) GetName() string{
    return p.name
}

func (p *People) GetAge() int{
    return p.age
}

type Teacher struct{
    People
    classroom string
}
func (tea *Teacher) run()  {
    fmt.Println(tea.name,"在跑步")
}
type Student struct{
    People
    classroom string
}
func (stu *Student) run()  {
    fmt.Println(stu.name,"在跑步")
}

下载链接

https://github.com/xcysuccess/go-demo/tree/master/hello

参考：

军哥分享 https://iwiki.woa.com/pages/viewpage.action?pageId=1864232161
interface{} https://www.cnblogs.com/maji233/p/11178413.html
go官方 https://github.com/golang/go/wiki/
封装继承多态 https://www.cnblogs.com/derek1184405959/p/11306426.html

原文地址：https://cloud.tencent.com/developer/article/2137434