Golang之interface（多态，类型断言）

多态用法

package main

//一种事物的多种形态，都可以按照统一的接口进行操作
//多态
import (
    "fmt"
    "math/rand"
    "sort"
)

type Student struct {
    Name     string
    Id       string
    Age      int
    sortType int
}
type Book struct {
    Name   string
    Author string
}

//切片默认传地址
type StudentArray []Student

func (p StudentArray) Len() int {
    return len(p)
}

func (p StudentArray) Less(i, j int) bool {
    return p[i].Name < p[j].Name
}

func (p StudentArray) Swap(i, j int) {
    p[i], p[j] = p[j], p[i]
}

func main() {
    var stus StudentArray
    for i := 0; i < 10; i++ {
        stu := Student{
            Name: fmt.Sprintf("stu%d", rand.Intn(100)),
            Id:   fmt.Sprintf("110%d", rand.Int()),
            Age:  rand.Intn(100),
        }
        stus = append(stus, stu)
    }
    for _, v := range stus {
        fmt.Println(v)
    }

    fmt.Println("\n\n")
    sort.Sort(stus)
    for _, v := range stus {
        fmt.Println(v)
    }
}

 接口嵌套

package main

import "fmt"
//接口嵌套 一个接口可以嵌套在另外的接口
type Reader interface {
    Read()
}
type Writer interface {
    Write()
}
type ReadWriter interface {
    Reader
    Writer
}
type File struct {
}

func (f *File) Read() {
    fmt.Println("read data")
}

func (f *File) Write() {
    fmt.Print("write data")
}
func Test(rw ReadWriter) {
    rw.Read()
    rw.Write()
}

func main() {
    var f File
    Test(&f)
}

 类型断言

package main

import "fmt"

type Student struct {
    Name string
    Sex  string
}
//类型断言
//一个判断传入参数类型的函数
func just(items ...interface{}) {
    for index, v := range items {
        switch v.(type) {
        case bool:
            fmt.Printf("%d params is bool,value is %v\n", index, v)
        case int, int64, int32:
            fmt.Printf("%d params is int,value is %v\n", index, v)
        case float32, float64:
            fmt.Printf("%d params is float,value is %v\n", index, v)
        case string:
            fmt.Printf("%d params is string,value is %v\n", index, v)
        case Student:
            fmt.Printf("%d params student,value is %v\n", index, v)
        case *Student:
            fmt.Printf("%d params *student,value is %v\n", index, v)

        }
    }
}
func main() {
    var b Student = Student{
        Name: "stu01",
        Sex:  "female",
    }
    just(28, 8.2, "this is a test", b, &b)

}