接口 interface 

package main

import "fmt"

//动物
type dongwu interface {
   wangwang()
}

//狗
type dog struct {
   name string
}

func (d dog) wangwang()  {
   fmt.Println(d.name,"会 汪汪汪")
}

//猴子
type monkey struct {
   name string
}

func (d monkey) wangwang()  {
   fmt.Println(d.name,"会 爬树")
}

func da(d dongwu)  {
   d.wangwang()
}

func main()  {
   d := dog{name:"狼狗"}
   da(d)

   b := monkey{name:"大嘴猴"}
   da(b)
}

接口嵌套/一个结构体多个接口(接口里的方法体继承就需要实现)

package main

import "fmt"

//接口嵌套
type Monkey interface {
   dongwu
   lingzhang
}

//动物
type dongwu interface {
   wangwang()
}

//灵长动物
type lingzhang interface {
   sikao()
}

//狗
type dog struct {
   name string
}

func (d dog) wangwang()  {
   fmt.Println(d.name,"会 汪汪汪")
}

func (d dog) sikao()  {
   fmt.Println(d.name,"会 思考")
}

//猴子
type monkey struct {
   name string
}

func (d monkey) wangwang()  {
   fmt.Println(d.name,"会 爬树")
}

func (d monkey) sikao()  {
   fmt.Println(d.name,"会 思考")
}

func da(d Monkey)  {
   d.wangwang()
}
func sk(d Monkey)  {
   d.sikao()
}

func main()  {
   dd := dog{name:"狼狗"}
   da(dd)

   b := monkey{name: "大嘴猴"}
   da(b)
   sk(b)
}

空接口/作为参数

func test1(a interface{})  {
   fmt.Printf("%T %#v \n",a,a)
}

func main()  {

   //空接口
   var m1 map[string]interface{}
   m1 = make(map[string]interface{})
   m1["name"] = "张三"
   m1["age"] = 16
   m1["money"] = 12.56
   m1["is_boy"] = true
   m1["生日"] = time.Now().Unix()
   fmt.Printf("%T %#v \n",m1,m1)

   //作为参数
   test1(456.22)

}

类型断言

//判断类型是啥
func istype1(t interface{})  {
   fmt.Printf("%T \n",t)
   switch t.(type) {
   case int:
      fmt.Println("int 类型")
   case string:
      fmt.Println("string 类型")
   case byte:
      fmt.Println("byte 类型")
   case map[int]interface{}:
      fmt.Println("map[int]interface{} 类型")
   case bool:
      fmt.Println("bool 类型")
   case float64:
      fmt.Println("float64 类型")
   case int32:
      fmt.Println("float64 类型")
   }
}

func istype2(t interface{})  {
   fmt.Printf("%T \n",t)
   if str,ok:=t.(int);ok == false{
      fmt.Println("非int类型")
   }else{
      fmt.Println("int类型;值为: ",str)
   }
}

func main()  {
   istype1(123)
   istype1('1')
   istype1(false)
   istype2(false)
   istype2(456)
}

文件OS 读

import (
   "bufio"
   "fmt"
   "io"
   "io/ioutil"
   "os"
)

func du1()  {
   fileinfo,err := os.Open(`E:\Go\src\DarkHorse\studygo\day05\1.log`)
   defer fileinfo.Close()
   if err != nil{
      fmt.Println("打开文件出错",err)
      return
   }
   var info [10]byte
   //infos := make([]byte,188)
   for  {
      n,err:=fileinfo.Read(info[:])
      if err != io.EOF{
         fmt.Println("读完了",err)
         return
      }
      if err != nil{
         fmt.Println("读取文件出错",err)
         return
      }
      fmt.Println(n)
      fmt.Println(len(info))
      fmt.Println(string(info[:n]))
      if n < 10{
         return
      }
   }
}

//利用 bufio
func du2()  {
   fileobj,err:=os.Open(`E:\Go\src\DarkHorse\studygo\day05\1.log`)
   if err != nil{
      fmt.Println("文件打开失败")
   }
   defer fileobj.Close()

   reader := bufio.NewReader(fileobj)
   for {
      line,err := reader.ReadString('\n')
      fmt.Println(line)
      if err == io.EOF{
         fmt.Println("读完了啊")
         return
      }
      if err != nil{
         fmt.Println("伙计报错了",err)
         return
      }

   }



}

//读全部
func du3()  {
   ret,err := ioutil.ReadFile(`E:\Go\src\DarkHorse\studygo\day05\1.log`)
   if err != nil{
      fmt.Println("文件打开失败")
   }
   fmt.Print(string(ret))
}

func main()  {
   du3()
}

文件OS 写

func xie1()  {
   fileinfo,err := os.OpenFile(`E:\Go\src\DarkHorse\studygo\day05\2.log`,os.O_WRONLY|os.O_CREATE,0664)
   if err != nil{
      fmt.Println("文件打开失败",err)
   }
   defer  fileinfo.Close()

   fileinfo.Write([]byte("今天天气很好啊 \n"))
   fileinfo.WriteString("你说的对 ")
}

//缓存写
func xie2()  {
   fileinfo,err := os.OpenFile(`E:\Go\src\DarkHorse\studygo\day05\3.log`,os.O_WRONLY|os.O_CREATE,0664)
   if err != nil{
      fmt.Println("文件打开失败",err)
   }
   defer  fileinfo.Close()

   //整个缓存
   wr := bufio.NewWriter(fileinfo)
   wr.WriteString("12331231")

   wr.Flush() //最后写入文件


}

//直接全部写
func xie3()  {
   str := "阿斯蒂芬的共和国肺结核挂科就好"
   err := ioutil.WriteFile(`E:\Go\src\DarkHorse\studygo\day05\4.log`,[]byte(str),0666)
   if err != nil{
      fmt.Print("出错了")
      return
   }


}

func main()  {
   xie3()
}