Golang之interface（多態，類型斷言）

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多態用法

package main//一種事物的多種形態，都可以按照統一的介面進行操作//多態import (    "fmt"    "math/rand"    "sort")type Student struct {    Name     string    Id       string    Age      int    sortType int}type Book struct {    Name   string    Author string}//切片預設傳地址type StudentArray []Studentfunc (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)    }}

 介面嵌套

package mainimport "fmt"//介面嵌套 一個介面可以嵌套在另外的介面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)}

 類型斷言

package mainimport "fmt"type Student struct {    Name string    Sex  string}//類型斷言//一個判斷傳入參數類型的函數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)}